Aya Kamaya, MD

All Publications

• Inter-Reader Agreement for Contrast-Enhanced Ultrasound Liver Imaging Reporting and Data System Major Features and Final Categorization: A Subanalysis From a Prospective Multicenter Study. Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine Kuon Yeng Escalante, C. M., Siu Xiao, T., Kono, Y., Piscaglia, F., Wilson, S. R., Medellin, A., Rodgers, S. K., Planz, V., Kamaya, A., Fetzer, D. T., Berzigotti, A., Sidhu, P. S., Wessner, C. E., Bradigan, K., Eisenbrey, J. R., Forsberg, F., Lyshchik, A. 2024

  Abstract

  Contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) is used to definitively diagnose hepatocellular carcinoma (HCC) in patients at risk. However, the user variability associated with CEUS LI-RADS has not been validated in North American and European patients. This study aims to evaluate the inter-reader agreements of CEUS LI-RADS features for, and final categorization of, HCC in patients at risk.This retrospective multicenter clinical study used the database of a previous prospective multinational study, evaluating the accuracy of CEUS LI-RADS for HCC diagnosis in patients at risk. All cases were first evaluated by a site physician performing/supervising the CEUS examination. Randomly selected cases were re-evaluated by a blinded central reader. Final diagnosis was confirmed with the reference standard, which was a composite of imaging tests and histology. Cohen's kappa test was used to evaluate inter-reader agreement.This study included 150 liver nodules and 58.0% (87/150) were confirmed as HCC, 4.7% (7/150) non-HCC malignancies, 22.7% (34/150) had no confirmed final diagnosis, and 14.7% (22/150) were nonmalignant. Inter-reader agreements were substantial for CEUS LI-RADS categorization (κ = 0.61; 95% confidence interval [CI]: 0.51-0.71) and major features assessment (ranged κ = 0.64-0.78), LR-5 (κ = 0.65; 95% CI: 0.52-0.77), and LR-M (κ = 0.67; 95% CI: 0.44-0.90), while for LR-1 and LR-2 categorization was almost perfect (κ = 0.85; 95% CI: 0.65-1.00).Our study reported a substantial inter-reader agreement for overall CEUS LI-RADS categorization, especially for LR-5 and LR-M, and major imaging features of HCC, further confirming CEUS LI-RADS as a valuable and reliable tool for diagnosis of HCC.

  View details for DOI 10.1002/jum.16608

  View details for PubMedID 39470295

• Combining CEUS and CT/MRI LI-RADS major imaging features: diagnostic accuracy for classification of indeterminate liver observations in patients at risk for HCC. Abdominal radiology (New York) Siu Xiao, T., Kuon Yeng Escalante, C. M., Tahmasebi, A., Kono, Y., Piscaglia, F., Wilson, S. R., Medellin-Kowalewski, A., Rodgers, S. K., Planz, V., Kamaya, A., Fetzer, D. T., Berzigotti, A., Radu, I., Sidhu, P. S., Wessner, C. E., Bradigan, K., Eisenbrey, J. R., Forsberg, F., Lyshchik, A. 2024

  Abstract

  PURPOSE: To determine the diagnostic accuracy of combining CEUS and CT/MRI LI-RADS major imaging features for the improved categorization of liver observations indeterminate on both CT/MRI and CEUS.MATERIALS AND METHODS: A retrospective analysis using a database from a prospective study conducted at 11 centers in North America and Europe from 2018 to 2022 included a total of 109 participants at risk for HCC who had liver observations with indeterminate characterization (LR3, LR-4, and LR-M) on both CEUS and CT/MRI. The individual CEUS and CT/MRI LI-RADS major features were extracted from the original study and analyzed in various combinations. Reference standards included biopsy, explant histology, and follow-up CT/MRI. The diagnostic performance of the combinations of LI-RADS major features for definitive diagnosis of HCC was calculated. A reverse, stepwise logistical regression sub-analysis was also performed.RESULTS: This study included 114 observations indeterminate on both CT/MRI and CEUS. These observations were categorized as LR-3 (n=37), LR-4 (n=41), and LR-M (n=36) on CT/MRI and LR-3 (n=48), LR-4 (n=36), LR-M (n=29), and LR-TIV (n=1) on CEUS. Of them, 43.0% (49/114) were confirmed as HCC, 37.3% (43/114) non-malignant, and 19.3% (22/114) non-hepatocellular malignancies. The highest diagnostic accuracy among the combinations of imaging features was achieved in CT/MRI LR-3 observations, where the combination of CEUS arterial phase hyper-enhancement (APHE)+CT/MRI APHE had 96.7% specificity, 75.0% positive predictive value (PPV), and 86.5% accuracy for HCC.CONCLUSION: The combination of LI-RADS major features on CT/MRI and CEUS showed higher specificity, PPV, and accuracy compared to individual modalities' assessments, particularly for CT/MRI LR-3 observations.

  View details for DOI 10.1007/s00261-024-04625-w

  View details for PubMedID 39438285

• The Ovarian-Adnexal Reporting and Data System (O-RADS) US Score Effect on Surgical Resection Rate. Radiology Shen, L., Sadowski, E. A., Gupta, A., Maturen, K. E., Patel-Lippmann, K. K., Zafar, H. M., Kamaya, A., Antil, N., Guo, Y., Barroilhet, L. M., Jha, P. 2024; 313 (1): e240044

  Abstract

  Background The Ovarian-Adnexal Imaging Reporting and Data System (O-RADS) US risk score can be used to accurately stratify ovarian lesions based on morphologic characteristics. However, there are no large multicenter studies assessing the potential impact of using O-RADS US version 2022 risk score in patients referred for surgery for an ovarian or adnexal lesion. Purpose To retrospectively determine the proportion of patients with ovarian or adnexal lesions without acute symptoms who may have been managed conservatively by using the O-RADS US version 2022 risk score. Materials and Methods This multicenter retrospective study included patients with ovarian cystic lesions and nonacute symptoms who underwent surgical resection after US before the introduction of O-RADS US between January 2011 and December 2014. Investigators blinded to the final diagnoses recorded lesion imaging features and O-RADS US risk scores. The frequency of malignancy and the diagnostic performance of the risk score were calculated. The Mann-Whitney test and Fisher exact test were performed, with P < .05 indicating a statistically significant difference. Results A total of 377 patients with surgically resected lesions were included. Among the resected lesions, 42% (157 of 377) were assigned an O-RADS US risk score of 2. Of the O-RADS US 2 lesions, 54% (86 of 157) were nonneoplastic, 45% (70 of 157) were dermoids or other benign tumors, and less than 1% (one of 157) were malignant. Using O-RADS US 4 as the optimal threshold for malignancy prediction yielded a 94% (68 of 72) sensitivity, 64% (195 of 305) specificity, 38% (68 of 178) positive predictive value, and 98% (195 of 199) negative predictive value. Conclusion In patients without acute symptoms who underwent surgery for ovarian and adnexal lesions before the O-RADS US risk score was published, nearly half (42%) of surgically resected lesions retrospectively met the O-RADS US 2 version 2022 criteria. In these patients, imaging follow-up or conservative management could have been offered. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Fournier in this issue.

  View details for DOI 10.1148/radiol.240044

  View details for PubMedID 39377674

• Diagnostic performance of CT/MRI LI-RADS v2018 in non-cirrhotic hepatitis C virus infection. Abdominal radiology (New York) Cao, J. J., Shon, A., Yoon, L., Kamaya, A., Tse, J. R. 2024

  Abstract

  To evaluate the diagnostic performance of LI-RADS among patients with non-cirrhotic hepatitis C virus (HCV) infection.This retrospective, IRB-approved, single-center study included 66 observations from 43 adult patients (11 women, 32 men; median age 65 years). All patients received liver protocol CT or MRI from 2010 to 2023, had HCV, and did not have cirrhosis based on histopathology. Three board-certified abdominal radiologists blinded to histopathology and imaging follow-up assessed each observation for major features and final LI-RADS category, and inter-reader agreements with weighted kappa were calculated. The positive predictive value, sensitivity, specificity, and accuracy of in diagnosing HCC and overall malignancy was calculated.Of the 66 observations, 53 (80%) were malignant and 13 (20%) were benign. Positive predictive value for HCC was 0-0% for LR-1, 0-0% for LR-2, 0-33% for LR-3, 57-100% for LR-4, 98-100% for LR-5, 25-50% for LR-M, and 83-100% for LR-TIV. Positive predictive value for overall malignancy was 0-0% for LR-1, 0-0% for LR-2, 0-33% for LR-3, 57-100% for LR-4, 98-100% for LR-5, 100-100% for LR-M, and 100-100% for LR-TIV. For LR-5 in identifying HCC, sensitivity ranged from 74 to 90%, specificity from 94 to 100%, and accuracy from 80 to 91%. For the composite of LR-5, LR-M, or LR-TIV in identifying overall malignancy, sensitivity was 87-98%, specificity was 92-100%, and accuracy was 89-97%. The inter-reader agreement for major features varied from moderate to substantial, with substantial agreement for the final category.CT/MRI LI-RADS v2018 criteria can be applied to non-cirrhotic HCV patients with near-perfect specificity.

  View details for DOI 10.1007/s00261-024-04589-x

  View details for PubMedID 39400590

  View details for PubMedCentralID 8568358

• A Lexicon for First-Trimester US: Society of Radiologists in Ultrasound Consensus Conference Recommendations. American journal of obstetrics and gynecology Rodgers, S. K., Horrow, M. M., Doubilet, P. M., Frates, M. C., Kennedy, A., Andreotti, R., Brandi, K., Detti, L., Horvath, S. K., Kamaya, A., Koyama, A., Lema, P. C., Maturen, K. E., Morgan, T., Običan, S. G., Olinger, K., Sohaey, R., Senapati, S., Strachowski, L. M. 2024

  Abstract

  The Society of Radiologists in Ultrasound convened a multisociety panel to develop a first-trimester US lexicon based on scientific evidence, societal guidelines, and expert consensus that would be appropriate for imagers, clinicians, and patients. Through a modified Delphi process with consensus of at least 80%, agreement was reached for preferred terms, synonyms, and terms to avoid. An intrauterine pregnancy (IUP) is defined as a pregnancy implanted in a normal location within the uterus. In contrast, an ectopic pregnancy (EP) is any pregnancy implanted in an abnormal location, whether extrauterine or intrauterine, thus categorizing cesarean scar implantations as EPs. The term pregnancy of unknown location is used in the setting of a pregnant patient without evidence of a definite or probable IUP or EP at transvaginal US. Since cardiac development is a gradual process and cardiac chambers are not fully formed in the first trimester, the term cardiac activity is recommended in lieu of 'heart motion' or 'heartbeat.' The terms 'living' and 'viable' should also be avoided in the first trimester. 'Pregnancy failure' is replaced by early pregnancy loss (EPL). When paired with various modifiers, EPL is used to describe a pregnancy in the first trimester that may or will not progress, is in the process of expulsion, or has either incompletely or completely passed.

  View details for DOI 10.1016/j.ajog.2024.07.038

  View details for PubMedID 39198135

• Large language models' responses to liver cancer surveillance, diagnosis, and management questions: accuracy, reliability, readability. Abdominal radiology (New York) Cao, J. J., Kwon, D. H., Ghaziani, T. T., Kwo, P., Tse, G., Kesselman, A., Kamaya, A., Tse, J. R. 2024

  Abstract

  To assess the accuracy, reliability, and readability of publicly available large language models in answering fundamental questions on hepatocellular carcinoma diagnosis and management.Twenty questions on liver cancer diagnosis and management were asked in triplicate to ChatGPT-3.5 (OpenAI), Gemini (Google), and Bing (Microsoft). Responses were assessed by six fellowship-trained physicians from three academic liver transplant centers who actively diagnose and/or treat liver cancer. Responses were categorized as accurate (score 1; all information is true and relevant), inadequate (score 0; all information is true, but does not fully answer the question or provides irrelevant information), or inaccurate (score - 1; any information is false). Means with standard deviations were recorded. Responses were considered as a whole accurate if mean score was > 0 and reliable if mean score was > 0 across all responses for the single question. Responses were also quantified for readability using the Flesch Reading Ease Score and Flesch-Kincaid Grade Level. Readability and accuracy across 60 responses were compared using one-way ANOVAs with Tukey's multiple comparison tests.Of the twenty questions, ChatGPT answered nine (45%), Gemini answered 12 (60%), and Bing answered six (30%) questions accurately; however, only six (30%), eight (40%), and three (15%), respectively, were both accurate and reliable. There were no significant differences in accuracy between any chatbot. ChatGPT responses were the least readable (mean Flesch Reading Ease Score 29; college graduate), followed by Gemini (30; college) and Bing (40; college; p < 0.001).Large language models provide complex responses to basic questions on hepatocellular carcinoma diagnosis and management that are seldomly accurate, reliable, or readable.

  View details for DOI 10.1007/s00261-024-04501-7

  View details for PubMedID 39088019

  View details for PubMedCentralID 10366809

• A Lexicon for First-Trimester US: Society of Radiologists in Ultrasound Consensus Conference Recommendations. Radiology Rodgers, S. K., Horrow, M. M., Doubilet, P. M., Frates, M. C., Kennedy, A., Andreotti, R., Brandi, K., Detti, L., Horvath, S. K., Kamaya, A., Koyama, A., Lema, P. C., Maturen, K. E., Morgan, T., Običan, S. G., Olinger, K., Sohaey, R., Senapati, S., Strachowski, L. M. 2024; 312 (2): e240122

  Abstract

  The Society of Radiologists in Ultrasound convened a multisociety panel to develop a first-trimester US lexicon based on scientific evidence, societal guidelines, and expert consensus that would be appropriate for imagers, clinicians, and patients. Through a modified Delphi process with consensus of at least 80%, agreement was reached for preferred terms, synonyms, and terms to avoid. An intrauterine pregnancy (IUP) is defined as a pregnancy implanted in a normal location within the uterus. In contrast, an ectopic pregnancy (EP) is any pregnancy implanted in an abnormal location, whether extrauterine or intrauterine, thus categorizing cesarean scar implantations as EPs. The term pregnancy of unknown location is used in the setting of a pregnant patient without evidence of a definite or probable IUP or EP at transvaginal US. Since cardiac development is a gradual process and cardiac chambers are not fully formed in the first trimester, the term cardiac activity is recommended in lieu of 'heart motion' or 'heartbeat.' The terms 'living' and 'viable' should also be avoided in the first trimester. 'Pregnancy failure' is replaced by early pregnancy loss (EPL). When paired with various modifiers, EPL is used to describe a pregnancy in the first trimester that may or will not progress, is in the process of expulsion, or has either incompletely or completely passed. © RSNA and Elsevier, 2024 Supplemental material is available for this article. This article is a simultaneous joint publication in Radiology and American Journal of Obstetrics & Gynecology. All rights reserved. The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Either version may be used in citing this article. See also the editorial by Scoutt and Norton in this issue.

  View details for DOI 10.1148/radiol.240122

  View details for PubMedID 39189906

• Differentiation of Hepatocellular Adenoma Subtypes and Focal Nodular Hyperplasia on Gadoxetate Disodium-Enhanced MRI: An Updated Diagnostic Algorithm. AJR. American journal of roentgenology Cao, J. J., Shen, L., Yoon, L., Kamaya, A., Tse, J. R. 2024

  View details for DOI 10.2214/AJR.24.31628

  View details for PubMedID 39016449

• Diagnostic performance of CT/MRI LI-RADS v2018 in non-cirrhotic steatotic liver disease. European radiology Cao, J., Shon, A., Yoon, L., Kamaya, A., Tse, J. R. 2024

  Abstract

  OBJECTIVE: To assess the performance of computed tomography (CT)/magnetic resonance imaging (MRI) Liver Imaging Reporting and Data System (LI-RADS) among patients with non-cirrhotic steatotic liver disease (SLD).MATERIALS AND METHODS: This IRB-approved, retrospective study included 119 observations from 77 adult patients (36 women, 41 men; median 64 years) who underwent liver CT or MRI from 2010 to 2023. All patients had histopathologic evidence of SLD without cirrhosis. Three board-certified abdominal radiologists blinded to tissue diagnosis and imaging follow-up assessed observations with LI-RADS. The positive predictive value (PPV), sensitivity, specificity, accuracy, and inter-reader agreement were calculated.RESULTS: Seventy-five observations (63%) were benign and 44 (37%) were malignant. PPV for hepatocellular carcinoma (HCC) was 0-0% for LR-1, 0-0% for LR-2, 0-7% for LR-3, 11-20% for LR-4, 75-88% for LR-5, 0-8% for LR-M, and 50-75% for LR-TIV. For LR-5 in identifying HCC, sensitivity was 79-83%, specificity was 91-97%, and accuracy was 89-92%. For composite categories of LR-5, LR-M, or LR-TIV in identifying malignancy, sensitivity was 86-89%, specificity was 85-96%, and accuracy was 86-93%. The most common false positives for LR-5 were hepatocellular adenomas. Only 59-65% of HCCs showed non-peripheral washout at CT versus 67-83% at MRI, though nearly all had an enhancing capsule. PPV and accuracy of LR-5 for HCC did not differ by modality. Inter-reader agreement for major features ranged from 0.667 to 0.830 and was 0.766 for the final category.CONCLUSION: Despite challenges such as the lower prevalence of non-peripheral washout at CT and overlapping imaging features between HCC and hepatocellular adenomas, LI-RADS may serve as an effective tool in assessing focal liver lesions in SLD.CLINICAL RELEVANCE STATEMENT: LI-RADS in non-cirrhotic steatotic liver disease can effectively diagnose hepatocellular carcinoma and malignancy at computed tomography and magnetic resonance imaging, thereby guiding clinical management decisions and expediting patient care pathways.KEY POINTS: Performance of LI-RADS is unknown in non-cirrhotic patients with steatotic liver disease. LI-RADS 5 category showed a high pooled specificity of 91-97% for hepatocellular carcinoma. LI-RADS can non-invasively risk stratify focal liver observations in non-cirrhotic patients with steatotic liver disease.

  View details for DOI 10.1007/s00330-024-10846-w

  View details for PubMedID 38951191

• Clinical impact of CEUS on non-characterizable observations and observations with intermediate probability of malignancy on CT/MRI in patients at risk for HCC. Abdominal radiology (New York) Kono, Y., Piscaglia, F., Wilson, S. R., Medellin, A., Rodgers, S. K., Planz, V., Kamaya, A., Fetzer, D. T., Berzigotti, A., Sidhu, P. S., Wessner, C. E., Bradigan, K., Kuon Yeng Escalante, C. M., Siu Xiao, T., Eisenbrey, J. R., Forsberg, F., Lyshchik, A. 2024

  Abstract

  Hepatocellular carcinoma (HCC) is a unique cancer allowing tumor diagnosis with identification of definitive patterns of enhancement on contrast-enhanced imaging, avoiding invasive biopsy. However, it is still unclear to what extent Contrast-Enhanced Ultrasound (CEUS) is a clinically useful additional step when Computed tomography (CT) or Magnetic resonance imaging (MRI) are inconclusive.A prospective international multicenter validation study for CEUS Liver Imaging Reporting and Data System (LI-RADS) was conducted between January 2018 and August 2021. 646 patients at risk for HCC with focal liver lesions were enrolled. CEUS was performed using an intravenous ultrasound contrast agent within 4 weeks of CT/MRI. Liver nodules were categorized based on LI-RADS (LR) criteria. Histology or one-year follow-up CT/MRI imaging results were used as the reference standard. The diagnostic performance of CEUS was evaluated for inconclusive CT/MRI scan in two scenarios for which the AASLD recommends repeat imaging or imaging follow-up: observations deemed non-characterizable (LR-NC) or with indeterminate probability of malignancy (LR-3).75 observations on CT or MRI were categorized as LR-3 (n = 54) or LR-NC (n = 21) CEUS recategorization of such observations into a different LR category (namely, into one among LR-1, LR-2, LR-5, LR-M, or LR-TIV) resulted in management recommendation changes in 33.3% (25/75) and in all but one (96.0%, 24/25) observation, the new management recommendations were correct.CEUS LI-RADS resulted in management recommendations change in substantial number of liver observations with initial indeterminate CT/MRI characterization, identifying both non-malignant lesions and HCC, potentially accelerating the diagnostic process and alleviating the need for biopsy or follow-up imaging.gov number, NCT03318380.

  View details for DOI 10.1007/s00261-024-04305-9

  View details for PubMedID 38860996

  View details for PubMedCentralID 4531423

• Follow-up imaging and surgical costs associated with different guidelines for management of incidentally detected gallbladder polyps. Academic radiology Vo-Phamhi, J. M., Tiyarattanachai, T., Matuszczak, M., Shen, L., Kim, S., Kamaya, A. 2024

  Abstract

  To compare follow-up imaging and surgical cost implications of the Society of Radiologists in Ultrasound (SRU) guidelines, 2017 and 2022 European (EUR) guidelines, 2020 Canadian Association of Radiologists (CAR) recommendations, and 2013 American College of Radiology (ACR) White Paper for managing incidentally detected gallbladder polyps.253 consecutive patients with gallbladder polyps identified on ultrasound were independently reviewed by three radiologists for polyp size and morphology. Electronic medical records were reviewed for patient demographics, cholecystectomy (if performed) pathological findings, or any subsequent diagnosis of gallbladder cancer. For each patient, the following were calculated for each of the 5 guidelines studied: 1) number of recommended follow-up ultrasounds based on initial presentation, 2) number of surgical consultations recommended based on initial presentation, 3) number of surgical consultations recommended based on growth, and 4) associated imaging and surgical costs. Interrater agreement was calculated.The SRU 2022 guidelines suggested significantly fewer follow-up ultrasounds and surgical consultations, leading to a cost reduction of 96.5 % and 96.7 % compared to European 2022 and 2017, respectively; 86.5 % compared to CAR; and 86.2 % compared to ACR guidelines. With SRU Recommendations, the majority of gallbladder polyps would be classified as extremely low risk (68.4 %), 30.8 % low risk, and 0.8 % indeterminate risk. In our cohort, a single case of gallbladder cancer was identified (26 mm) which would be recommended for surgical consult by all guidelines.The SRU 2022 guidelines can lead to significant savings for patients, health systems, and society, while reducing unnecessary medical interventions for managing incidentally detected gallbladder polyps.

  View details for DOI 10.1016/j.acra.2024.05.034

  View details for PubMedID 38862347

• New LI-RADS Ultrasound Surveillance v2024: A Conversation With Working Group Cochair Dr Aya Kamaya. AJR. American journal of roentgenology Kamaya, A. 2024

  Abstract

  In this video article, Aya Kamaya, MD, cochair of the LI-RADS Ultrasound Surveillance Working Group, discusses the new LI-RADS Ultrasound Surveillance version 2024 recommendations.

  View details for DOI 10.2214/AJR.24.31501

  View details for PubMedID 38809124

• Patient-Friendly Summary of the ACR Appropriateness Criteria®: Acute Pelvic Pain in the Reproductive Age Group. Journal of the American College of Radiology : JACR Coughlin, C., Kamaya, A. 2024

  View details for DOI 10.1016/j.jacr.2024.04.019

  View details for PubMedID 38740117

• The Future Role of Abdominal US in Hepatocellular Carcinoma Surveillance. Radiology Mendiratta-Lala, M., Fetzer, D., Kamaya, A., Parikh, N. D., Singal, A. G. 2024; 311 (2): e232624

  Abstract

  Abdominal US is currently the best-validated surveillance strategy for hepatocellular carcinoma (HCC) in at-risk patients. It is the only modality shown to have completed all five phases of validation and can achieve high sensitivity and specificity for HCC detection, especially when conducted by expert sonographers in high-volume centers. However, US also has limitations, including operator dependency and varying sensitivity in clinical practice. Further, the sensitivity of US for early-stage HCC detection is lower in patients with obesity or nonviral liver disease, increasingly common populations undergoing surveillance. Imaging-based and blood-based surveillance strategies, including abbreviated MRI and biomarker panels, may overcome some limitations of US-based surveillance. Both strategies have promising test performance in phase II and phase III biomarker studies and are undergoing prospective validation. Considering the variation in HCC risk and test performance between patients, there will likely be a shift away from a one-size-fits-all approach and toward precision screening, in which the "best" test is selected based on individual patient characteristics. In this upcoming era of precision HCC screening among patients with cirrhosis, US will likely continue to have an important, albeit reduced, surveillance role.

  View details for DOI 10.1148/radiol.232624

  View details for PubMedID 38742973

• Editorial Comment: Validating Usage of the Society of Radiologists in Ultrasound Consensus Conference Recommendations for Management of Incidental Gallbladder Polyps. AJR. American journal of roentgenology Kamaya, A. 2024

  View details for DOI 10.2214/AJR.24.31062

  View details for PubMedID 38415579

• Management of incidentally detected gallbladder polyps: a review of clinical scenarios using the 2022 SRU gallbladder polyp consensus guidelines. Abdominal radiology (New York) Knight, J., Kamaya, A., Fetzer, D., Dahiya, N., Gabriel, H., Rodgers, S. K., Tublin, M., Walsh, A., Bingham, D., Middleton, W., Fung, C. 2024

  Abstract

  Gallbladder (GB) polyps are a common incidental finding on sonography, but only a small fraction of polyps become GB cancer. The Society of Radiologists in Ultrasound (SRU) consensus committee recently performed an extensive literature review and published guidelines for GB polyp follow-up/management to provide clarity among the many heterogeneous recommendations that are available to clinicians. As these guidelines have become adopted into clinical practice, challenging clinical scenarios have arisen including GB polyps in primary sclerosing cholangitis (PSC), high risk geographic/genetic patient populations, shrinking polyps, pedunculated vs sessile polyps, thin vs thick stalked polyps, vascular polyps and multiple polyps. According to the SRU guidelines, clinicians should refer to gastroenterology guidelines when managing GB polyps in patients with known PSC. If patients at high geographic/genetic risk develop GB polyps, 'extremely low risk' polyps may be managed as 'low risk' and 10-14mm 'extremely low risk' or '7-14mm' low risk polyps that decrease in size by≥4mm require no follow-up. Thin-stalked or pedunculated polyps are 'extremely low risk' and thick-stalked pedunculated polyps are 'low risk'. Sessile polyps are 'low risk' but should receive immediate specialist referral if features suggestive of GB cancer are present. Neither polyp multiplicity nor vascularity impact risk of GB cancer and follow up should be based on morphology alone.

  View details for DOI 10.1007/s00261-024-04197-9

  View details for PubMedID 38411693

• Establishing a Point-of-Care Ultrasound (POCUS) Program: An Institutional Approach for Developing a POCUS Program Infrastructure. Journal of the American College of Radiology : JACR Shen, L., Lobo, V. E., Cordova, D., Larson, D. B., Kamaya, A. 2023

  Abstract

  Point of care ultrasound (POCUS) is rapidly accelerating in adoption and applications outside of the traditional realm of diagnostic radiology departments. While utilization of this imaging technology in a distributed fashion has great potential, there are many associated challenges. To address these challenges, we developed an enterprise-wide POCUS program at our institution (Stanford Health Care). Here, we share our experience, the governance organization, our approach to device and information security, training, and quality assurance. We also share our basic principles we use to guide our approach to manage these challenges. Through our work, we have learned that a foundational framework of defining POCUS, the different levels of POCUS use, and delineating program management elements are critical. We hope our experience may be helpful to others who are also interested in POCUS or in the process of creating a POCUS program in their institution. With a clearly established framework, patient safety and quality of care are improved for everyone.

  View details for DOI 10.1016/j.jacr.2023.10.026

  View details for PubMedID 37984768

• CLINICAL IMPACT OF CEUS ON INDETERMINATE LIVER NODULES ON MRI: SUB-ANALYSIS FROM A PROSPECTIVE MULTICENTER TRIAL Kono, Y., Piscaglia, F., Wilson, S. R., Medellin, A., Rodgers, S. K., Sidhu, P. S., Kamaya, A., Fetzer, D., Planz, V., Berzigotti, A., Finch, L., Wessner, C., Bradigan, K., Eisenbrey, J., Forsberg, F., Lyshchik, A. LIPPINCOTT WILLIAMS & WILKINS. 2023: S96-S97

  View details for Web of Science ID 001094865400094

• Reply to "Improving Accuracy in ChatGPT". AJR. American journal of roentgenology Cao, J. J., Kamaya, A., Tse, J. R. 2023: 1-2

  View details for DOI 10.2214/AJR.23.29949

  View details for PubMedID 37703485

• Clinical validation of contrast-enhanced ultrasound liver imaging reporting and data system in a prospective multinational study in North America and Europe. Hepatology (Baltimore, Md.) Lyshchik, A. A., Wessner, C. E., Bradigan, K., Eisenbrey, J. R., Forsberg, F., Yi, M., Keith, S. W., Kono, Y., Wilson, S. R., Medellin, A., Rodgers, S. K., Planz, V., Kamaya, A., Finch, L., Fetzer, D., Berzigotti, A., Sidhu, P. S., Piscaglia, F., CEUS LI-RADS Trial Group, Yusuf, G. T., Suddle, A., Rafailidis, V. D., Mulazzani, L., Granito, A., Terzi, E., Forgione, A., Giamperoli, A., Stefanini, B., Radu, I., Singal, A. 2023

  Abstract

  BACKGROUND AIMS: The objective of this study is to determine diagnostic accuracy of the American College of Radiology Contrast-Enhanced Ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) LR-5 characterization for HCC diagnosis in North American or European patients.APPROACH RESULTS: Prospective multinational cohort study was performed from 01/2018 through 11/2022 at 11 academic and nonacademic centers in North America and Europe. Patients at risk for HCC with at least one liver observation not previously treated, identified on ultrasound (US) or multiphase CT or MRI performed as a part of standard clinical care were eligible for the study. All participants were examined with CEUS of the liver within 4 weeks of CT / MRI or tissue diagnosis to characterize up to 2 liver nodules per participant using ACR CEUS LI-RADS. Definite HCC diagnosis on the initial CT/MRI, imaging follow-up, or histology for CT/MRI-indeterminate nodules were used as reference standard. A total 545 nodules had confirmed reference standard in 480 patients, 73.8% were HCC, 5.5% other malignancy, and 20.7% were non-malignant. The specificity of CEUS LR-5 for HCC was 95.1% (95% CI 90.1% - 97.7%), sensitivity 62.9% (95% CI 57.9%-67.7%), Positive Predictive Value (PPV) 97.3% (95% CI 94.5% - 98.7%), and Negative Predictive Value (NPV) 47.7% (95% CI 41.7% - 53.8%). In addition, benign CEUS characterization (LR-1 or LR-2) had 100% specificity and 100% PPV for non-malignant liver nodules.CONCLUSIONS: CEUS LI-RADS characterization provides accurate categorization of liver nodules in participants at risk for HCC. ClinicalTrials.gov ID NCT03318380.

  View details for DOI 10.1097/HEP.0000000000000558

  View details for PubMedID 37548928

• Accuracy of Information Provided by ChatGPT Regarding Liver Cancer Surveillance and Diagnosis. AJR. American journal of roentgenology Cao, J. J., Kwon, D. H., Ghaziani, T. T., Kwo, P., Tse, G., Kesselman, A., Kamaya, A., Tse, J. R. 2023

  View details for DOI 10.2214/AJR.23.29493

  View details for PubMedID 37222278

• External Validation of a Five-Tiered CT Algorithm for the Diagnosis of Clear-Cell Renal Cell Carcinoma: A Retrospective Five-Reader Study. AJR. American journal of roentgenology Lemieux, S., Shen, L., Liang, T., Lo, E., Chu, Y., Kamaya, A., Tse, J. R. 2023

  Abstract

  Background: A 5-tiered CT algorithm was proposed in 2022 for predicting whether a small (cT1a) solid renal mass represents clear-cell renal cell carcinoma (ccRCC). Purpose: To perform an external-validation study of the proposed CT algorithm for diagnosis of ccRCC among small solid renal masses. Methods: This retrospective study included 93 patients [median age, 62 years; 42 women, 51 men] with 97 small solid renal masses on corticomedullary-phase contrast-enhanced CT performed between January 2012 and July 2022 that underwent surgical resection. Five readers (three attending radiologists, two clinical fellows) independently evaluated masses for mass-to-cortex corticomedullary attenuation ratio and heterogeneity score; these scores were used to derive the CT score by the previously proposed CT algorithm. The CT score's sensitivity, specificity, and PPV for ccRCC were calculated at threshold of ≥4, and NPV for ccRCC was calculated at threshold of ≥3 (consistent with thresholds in studies of the MRI-based clear-cell likelihood score and the CT algorithm's initial study). The CT score's sensitivity and specificity for papillary RCC were calculated at a threshold of ≤2. Interreader agreement was assessed using Gwet's AC1. Results: Overall, 61/97 (63%) masses were malignant; 44/97 (44%) were ccRCC. Across readers, CT score had sensitivity ranging from 47% to 95% [pooled sensitivity, 74% (95% CI, 68-80%)], specificity ranging from 19% to 83% [pooled specificity, 59% (95% CI, 52-67%)], PPV ranging from 48% to 76% [pooled PPV, 59% (95% CI, 49-71%)], and NPV ranging from 83% to 100% [pooled NPV, 90% (95% CI, 84-95%)], for ccRCC. CT score ≤2 had sensitivity ranging from 44% to 100% and specificity ranging from 77% to 98% for papillary RCC (representing 9/97 masses). Interreader agreement was substantial for attenuation score (AC1=0.70), poor for heterogeneity score (AC1=0.17), fair for 5-tiered CT score (AC1=0.32), and fair for dichotomous CT score at threshold of ≥4 (AC1=0.24; 95% CI, 0.14-0.33). Conclusion: The 5-tiered CT algorithm for evaluation of small solid renal masses was tested in an external sample and showed high NPV for ccRCC. Clinical Impact: The CT algorithm may be used for risk stratification and patient selection for active surveillance by identifying patients unlikely to have ccRCC.

  View details for DOI 10.2214/AJR.23.29151

  View details for PubMedID 37162037

• Patient-Friendly Summary of the ACR Appropriateness Criteria®: Management of Liver Cancer. Journal of the American College of Radiology : JACR Greben, S., Kamaya, A. 2023

  View details for DOI 10.1016/j.jacr.2023.01.010

  View details for PubMedID 36997104

• Diagnostic performance of the "drooping" sign in CT diagnosis of exophytic renal angiomyolipoma. Abdominal radiology (New York) Shen, L., Nawaz, R., Tse, J. R., Negrete, L. M., Lubner, M. G., Toia, G. V., Liang, T., Wentland, A. L., Kamaya, A. 2023

  Abstract

  To evaluate the prevalence of angular interface and the "drooping" sign in exophytic renal angiomyolipomas (AMLs) and the diagnostic performance in differentiating exophytic lipid-poor AMLs from other solid renal masses.This IRB-approved, two-center study included 185 patients with 188 exophytic solid renal masses < 4 cm with histopathology and pre-operative CT within 30 days of surgical resection or biopsy. Images were reviewed for the presence of angular interface and the "drooping" sign qualitatively by three readers blinded to the final diagnosis, with majority rules applied. Both features were assessed quantitatively by cohort creators (who are not readers) independently. Free-marginal kappa was used to assess inter-reader agreement and agreement between two methods assessing each feature. Fisher's exact test, Mann-Whitney test, and multivariable logistic regression with two-tailed p < 0.05 were used to determine statistical significance. Diagnostic performance was assessed.Ninety-four patients had 96 AMLs, and 91 patients had 92 non-AMLs. Seventy-four (77%) of AMLs were lipid-poor based on quantitative assessment on CT. The presence of angular interface and the "drooping" sign by both qualitative and quantitative assessment were statistically significantly associated with AMLs (39% (qualitative) and 45% (quantitative) vs 15% (qualitative) and 13% (quantitative), and 48% (qualitative) and 43% (quantitative) vs 4% (qualitative) and 1% (quantitative), respectively, all p < 0.001) in univariable analysis. In multivariable analysis, only the "drooping" sign in either qualitative or quantitative assessment was a statistically significant predictor of AMLs (both p < 0.001). Inter-reader agreement for the "drooping" sign was moderate (k = 0.55) and for angular interface was fair (k = 0.33). Agreement between the two methods of assessing the "drooping" sign was substantial (k = 0.84) and of assessing the angular interface was moderate (k = 0.59). The "drooping" sign both qualitatively and quantitatively, alone or in combination of angular interface, had very high specificity (96-100%) and positive predictive value (PPV) (89-100%), moderate negative predictive value (62-68%), but limited sensitivity (23-49%) for lipid-poor AMLs.The "drooping" sign by both qualitative and quantitative assessment is highly specific for lipid-rich and lipid-poor AMLs. This feature alone or in combination with angular interface can aid in CT diagnosis of lipid-poor AMLs with very high specificity and PPV.

  View details for DOI 10.1007/s00261-023-03880-7

  View details for PubMedID 36947205

  View details for PubMedCentralID 4040184

• Hepatocellular Adenomas: Molecular Basis and Multimodality Imaging Update. Radiographics : a review publication of the Radiological Society of North America, Inc Tse, J. R., Felker, E. R., Naini, B. V., Shen, L., Shen, J., Lu, D. S., Kamaya, A., Raman, S. S. 2023; 43 (3): e220134

  Abstract

  Hepatocellular adenomas (HCAs) are a family of liver tumors that are associated with variable prognoses. Since the initial description of these tumors, the classification of HCAs has expanded and now includes eight distinct genotypic subtypes based on molecular analysis findings. These genotypic subtypes have unique derangements in their cellular biologic makeup that determine their clinical course and may allow noninvasive identification of certain subtypes. Multiphasic MRI performed with hepatobiliary contrast agents remains the best method to noninvasively detect, characterize, and monitor HCAs. HCAs are generally hypointense during the hepatobiliary phase; the beta-catenin-mutated exon 3 subtype and up to a third of inflammatory HCAs are the exception to this characterization. It is important to understand the appearances of HCAs beyond their depictions at MRI, as these tumors are typically identified with other imaging modalities first. The two most feared related complications are bleeding and malignant transformation to hepatocellular carcinoma, although the risk of these complications depends on tumor size, subtype, and clinical factors. Elective surgical resection is recommended for HCAs that are persistently larger than 5 cm, adenomas of any size in men, and all beta-catenin-mutated exon 3 HCAs. Thermal ablation and transarterial embolization are potential alternatives to surgical resection. In the acute setting of a ruptured HCA, patients typically undergo transarterial embolization with or without delayed surgical resection. This update on HCAs includes a review of radiologic-pathologic correlations by subtype and imaging modality, related complications, and management recommendations. © RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

  View details for DOI 10.1148/rg.220134

  View details for PubMedID 36821508

• LI-RADS: Looking Back, Looking Forward. Radiology Chernyak, V., Fowler, K. J., Do, R. K., Kamaya, A., Kono, Y., Tang, A., Mitchell, D. G., Weinreb, J., Santillan, C. S., Sirlin, C. B. 2023: 222801

  Abstract

  Since its initial release in 2011, the Liver Imaging Reporting and Data System (LI-RADS) has evolved and expanded in scope. It started as a single algorithm for hepatocellular carcinoma (HCC) diagnosis with CT or MRI with extracellular contrast agents and has grown into a multialgorithm network covering all major liver imaging modalities and contexts of use. Furthermore, it has developed its own lexicon, report templates, and supplementary materials. This article highlights the major achievements of LI-RADS in the past 11 years, including adoption in clinical care and research across the globe, and complete unification of HCC diagnostic systems in the United States. Additionally, the authors discuss current gaps in knowledge, which include challenges in surveillance, diagnostic population definition, perceived complexity, limited sensitivity of LR-5 (definite HCC) category, management implications of indeterminate observations, challenges in reporting, and treatment response assessment following radiation-based therapies and systemic treatments. Finally, the authors discuss future directions, which will focus on mitigating the current challenges and incorporating advanced technologies. Tha authors envision that LI-RADS will ultimately transform into a probability-based system for diagnosis and prognostication of liver cancers that will integrate patient characteristics and quantitative imaging features, while accounting for imaging modality and contrast agent.

  View details for DOI 10.1148/radiol.222801

  View details for PubMedID 36853182

• Growth Kinetics of Pancreatic Neuroendocrine Neoplasms by Histopathologic Grade. Pancreas Cao, J. J., Shen, L., Visser, B. C., Yoon, L., Kamaya, A., Tse, J. R. 2023; 52 (2): e135-e143

  Abstract

  The aims of the study are to describe the growth kinetics of pathologically proven, treatment-naive pancreatic neuroendocrine neoplasms (panNENs) at imaging surveillance and to determine their association with histopathologic grade and Ki-67.This study included 100 panNENs from 95 patients who received pancreas protocol computed tomography or magnetic resonance imaging from January 2005 to July 2022. All masses were treatment-naive, had histopathologic correlation, and were imaged with at least 2 computed tomography or magnetic resonance imaging at least 90 days apart. Growth kinetics was assessed using linear and specific growth rate, stratified by grade and Ki-67. Masses were also assessed qualitatively to determine other possible imaging predictors of grade.There were 76 grade 1 masses, 17 grade 2 masses, and 7 grade 3 masses. Median (interquartile range) linear growth rates were 0.06 cm/y (0-0.20), 0.40 cm/y (0.22-1.06), and 2.70 cm/y (0.41-3.89) for grade 1, 2, and 3 masses, respectively (P < 0.001). Linear growth rate correlated with Ki-67 with r2 of 0.623 (P < 0.001). At multivariate analyses, linear growth rate was the only imaging feature significantly associated with grade (P = 0.009).Growth kinetics correlate with Ki-67 and grade. Grade 1 panNENs grow slowly versus grade 2-3 panNENs.

  View details for DOI 10.1097/MPA.0000000000002221

  View details for PubMedID 37523605

• Charachterization of spatially mapped volumetric molecular ultrasound signals for predicting response to anti-vascular therapy. Scientific reports Keller, C. A., Zarkesh, S., Zhou, J., Lutz, A. M., Hristov, D., Kamaya, A., El Kaffas, A. 2023; 13 (1): 1686

  Abstract

  Quantitative three-dimensional molecular ultrasound is a promising technology for longitudinal imaging applications such as therapy monitoring; the risk profile is favorable compared to positron emission tomography and computed tomography. However, clinical translation of quantitative methods for this technology are limited in that they assume that tumor tissues are homogeneous, and often depend on contrast-destruction events that can produce unintended bioeffects. Here, we develop quantitative features (henceforth image features) that capture tumor spatial information, and that are extracted without contrast destruction. We compare these techniques with the contrast-destruction derived differential targeted enhancement parameter (dTE) in predicting response to therapy. We found thirty-three reproducible image features that predict response to antiangiogenic therapy, without the need for a contrast agent disruption pulse. Multiparametric analysis shows that several of these image features can differentiate treated versus control animals with comparable performance to post-destruction measurements, suggesting that these can potentially replace parameters such as the dTE. The highest performing pre-destruction image features showed strong linear correlations with conventional dTE parameters with less overall variance. Thus, our study suggests that image features obtained during the wash in of the molecular agent, pre-destruction, may replace conventional post-destruction image features or the dTE parameter.

  View details for DOI 10.1038/s41598-022-26273-0

  View details for PubMedID 36717575

• Universal Liver Imaging Lexicon: Imaging Atlas for Research and Clinical Practice. Radiographics : a review publication of the Radiological Society of North America, Inc Fowler, K. J., Bashir, M. R., Fetzer, D. T., Kitao, A., Lee, J. M., Jiang, H., Kielar, A. Z., Ronot, M., Kamaya, A., Marks, R. M., Elsayes, K. M., Tang, A., Sirlin, C. B., Chernyak, V. 2023; 43 (1): e220066

  Abstract

  The use of standardized terms in assessing and reporting disease processes has well-established benefits, such as clear communication between radiologists and other health care providers, improved diagnostic accuracy and reproducibility, and the enhancement and facilitation of research. Recently, the Liver Imaging Reporting and Data System (LI-RADS) Steering Committee released a universal liver imaging lexicon. The current version of the lexicon includes 81 vetted and precisely defined terms that are relevant to acquisition of images using all major liver imaging modalities and contrast agents, as well as lesion- and organ-level features. Most terms in the lexicon are applicable to all patients undergoing imaging of the liver, and only a minority of the terms are strictly intended to be used for patients with high risk factors for hepatocellular carcinoma. This pictorial atlas familiarizes readers with the liver imaging lexicon and includes discussion of general concepts, providing sample definitions, schematics, and clinical examples for a subset of the terms in the liver imaging lexicon. The authors discuss general, technical, and imaging feature terms used commonly in liver imaging, with the goal of illustrating their use for clinical and research applications. Work of the U.S. Government published under an exclusive license with the RSNA. Online supplemental material is available for this article.

  View details for DOI 10.1148/rg.220066

  View details for PubMedID 36427260

• Universal Liver Imaging Lexicon: Imaging Atlas for Research and Clinical Practice (vol 43, e220066, 2023) RADIOGRAPHICS Fowler, K. J., Bashir, M. R., Fetzer, D. T., Kitao, A., Lee, J., Jiang, H., Kielar, A. Z., Ronot, M., Kamaya, A., Marks, R. M., Elsayes, K. M., Tang, A., Sirlin, C. B., Chernyak, V. 2023; 43 (1): e239001

  View details for DOI 10.1148/rg.239001

  View details for Web of Science ID 001081137900011

  View details for PubMedID 36701248

• Patient-Friendly Summary of the ACR Appropriateness Criteria Acute Pyelonephritis: 2022 Update. Journal of the American College of Radiology : JACR Liang, E., Kamaya, A. 2022

  View details for DOI 10.1016/j.jacr.2022.07.015

  View details for PubMedID 36529607

• Diagnostic performance of hypoechoic perinephric fat as a predictor of prediabetes and diabetes. Abdominal radiology (New York) Shen, L., Tse, J. R., Negrete, L. M., Shon, A., Yoon, L., Liang, T., Kamaya, A. 2022

  Abstract

  To evaluate prevalence and predictive value of hypoechoic perinephric fat (HPF) in patients with prediabetes and diabetes compared to non-diabetics.Of 240 patients with renal ultrasound and hemoglobin A1c (HbA1c) measurements, 114 patients had either prediabetes (HbA1c 5.7-6.4%) or diabetes (HbA1c ≥ 6.5%), and 126 patients did not. Two radiologists (blinded to diagnosis) reviewed images and discrepancies were resolved by a third. Inter-reader agreement was compared using free-marginal kappa and intraclass correlation coefficient. Fisher's exact test, Mann-Whitney test, multivariable logistic regression, and Spearman's rank correlation test with two-tailed p < 0.05 were used to determine statistical significance.HPF was exclusively identified in prediabetic and diabetic patients with a prevalence of 23% (vs 0%; p < 0.001). Identification of HPF had almost perfect inter-reader agreement (k = 0.94) and was statistically significant (p = 0.034) while controlling for body mass index (BMI) and estimated glomerular filtration rate in multivariable analysis. HPF had extremely high specificity and positive predictive value (100% for both) in patients with prediabetes and diabetes although it was not a sensitive finding (23% sensitivity). In patients with prediabetes and diabetes, those with HPF were statistically significantly more likely to have chronic kidney disease (CKD) (p = 0.003). There was no statistically significant difference in BMI, stages of CKD, and types of diabetes.Hypoechoic perirenal fat has almost perfect inter-reader agreement and is highly specific for and predictive of prediabetes and diabetes. Its presence may also help identify those with chronic kidney disease among prediabetic and diabetic patients.

  View details for DOI 10.1007/s00261-022-03763-3

  View details for PubMedID 36480029

• Outcomes of Bosniak Classification Version 2019 Class IIF Cystic Renal Masses at Imaging Surveillance. AJR. American journal of roentgenology Shen, L., Yoon, L., Chung, B. I., Kamaya, A., Tse, J. R. 2022

  Abstract

  Background: Bosniak classification system version 2019 (v2019) recommends that class IIF masses undergo follow-up imaging at 6 months, 12 months, and then annually for 5 years. The frequency and timing of upgrade on follow-up imaging are incompletely understood. Purpose: To describe the temporal evolution of Bosniak v2019 class IIF cystic renal masses, with attention to outcomes at 6-month follow-up, time to class upgrade, and malignant histologic diagnoses. Methods: This retrospective study included 219 patients (91 women, 128 men; median age, 72 years) with 246 localized class IIF masses from January 2005 to June 2022. Patients underwent both a baseline and at least one follow-up renal-mass protocol contrast-enhanced CT or MRI. Two radiologists evaluated masses at all follow-up time points to categorize masses as downgraded (class I or II), stable (localized class IIF), or upgraded (class III or IV, solid, or ≥T3a, N1, or M1 disease); a third radiologist resolved discrepancies. Incidence rate of upgrade was determined. Histopathologic outcomes were assessed for resected masses. Results: Median follow-up was 28.4 months (IQR, 13.7-59.4 months). At 6-month follow-up, 5 (2%) masses were downgraded, 241 (98%) were stable, and none were upgraded. Based on final follow-up, 14 (6%) masses were downgraded, 223 (91%) were stable, and 9 (4%) were upgraded. All upgrade events entailed a class increase to III (n=7) or IV (n=2); no mass became solid or developed T3, N1, or M1 disease. Among the nine upgraded masses, median time to upgrade was 53.5 months (IQR, 23.2-63.7 months). Incidence rate of upgrade was 3.006 per 100,000 person-days (95% CI, 1.466-5.516). Ten masses were resected; histopathology was benign in six, and malignant in four. Of the four malignant masses, one was upgraded to class III after 15 months of preoperative follow-up imaging, and three remained class IIF on preoperative follow-up imaging. No resected malignant mass developed postoperative recurrence. Conclusion: Bosniak v2019 class IIF masses are unlikely to represent aggressive malignancy; only 4% were upgraded over time, and never on initial 6-month follow-up. Clinical Impact: The currently recommended initial 6-month follow-up imaging examination for class IIF masses is of questionable clinical utility.

  View details for DOI 10.2214/AJR.22.28599

  View details for PubMedID 36416398

• Differentiation of benign from malignant solid renal lesions using CT-based radiomics and machine learning: comparison with radiologist interpretation. Abdominal radiology (New York) Wentland, A. L., Yamashita, R., Kino, A., Pandit, P., Shen, L., Brooke Jeffrey, R., Rubin, D., Kamaya, A. 2022

  Abstract

  PURPOSE: To assess the performance of a machine learning model trained with contrast-enhanced CT-based radiomics features in distinguishing benign from malignant solid renal masses and to compare model performance with three abdominal radiologists.METHODS: Patients who underwent intra-operative ultrasound during a partial nephrectomy were identified within our institutional database, and those who had pre-operative contrast-enhanced CT examinations were selected. The renal masses were segmented from the CT images and radiomics features were derived from the segmentations. The pathology of each mass was identified; masses were labeled as either benign [oncocytoma or angiomyolipoma (AML)] or malignant [clear cell, papillary, or chromophobe renal cell carcinoma (RCC)] depending on the pathology. The data were parsed into a 70/30 train/test split and a random forest machine learning model was developed to distinguish benign from malignant lesions. Three radiologists assessed the cohort of masses and labeled cases as benign or malignant.RESULTS: 148 masses were identified from the cohort, including 50 benign lesions (23 AMLs, 27 oncocytomas) and 98 malignant lesions (23 clear cell RCC, 44 papillary RCC, and 31 chromophobe RCCs). The machine learning algorithm yielded an overall accuracy of 0.82 for distinguishing benign from malignant lesions, with an area under the receiver operating curve of 0.80. In comparison, the three radiologists had significantly lower accuracies (p=0.02) ranging from 0.67 to 0.75.CONCLUSION: A machine learning model trained with CT-based radiomics features can provide superior accuracy for distinguishing benign from malignant solid renal masses compared to abdominal radiologists.

  View details for DOI 10.1007/s00261-022-03735-7

  View details for PubMedID 36370180

• Positive predictive value of LI-RADS US-3 observations: multivariable analysis of clinical and imaging features. Abdominal radiology (New York) Tse, J. R., Shen, L., Tiyarattanachai, T., Bird, K. N., Liang, T., Yoon, L., Kamaya, A. 2022

  Abstract

  PURPOSE: To determine how clinical and imaging features affect the positive predictive values (PPV) of US-3 observations.METHODS: In this retrospective study, 10,546 adult patients who were high risk for hepatocellular carcinoma (HCC) from 2017 to 2021 underwent ultrasound screening/surveillance. Of these, 225 adult patients (100 women, 125 men) with an US-3 observation underwent diagnostic characterization with multiphasic CT (93; 41%), MRI (130; 58%), or contrast-enhanced ultrasound (2; 1%). US-3 observations included focal observations≥10mm in 216 patients and new venous thrombi in 9 patients. PPV with 95% confidence intervals were calculated using diagnostic characterization as the reference standard. Multivariable analysis of clinical and imaging features was performed to determine the strongest associations with cancer.RESULTS: Overall PPV for an US-3 observationwas 33% (27-39%) for at least intermediate probability of cancer (≥LR-3) and 15% (10-20%) for at least probable cancer (≥LR-4). At multivariable analysis, cirrhosis had the strongest effect size for at least probable cancer (p<0.001; odds ratio OR 20.4), followed by observation size (p<0.001; OR 2.65) and age (p=0.004; OR 1.05). Alpha-fetoprotein, visualization score, and observation echogenicity were not statistically significant associations. Modality (MRI versus CT) did not affect PPV. Due to the large effect of cirrhosis, PPV was then stratified by the presence (n=116; 52%) or absence (n=109; 48%) of cirrhosis. For at least probable cancer (≥LR-4), PPV increased from 4% (0-7%; non-cirrhotic) to 26% (18-34%; p<0.001; cirrhosis).CONCLUSION: Cirrhosis most strongly affects PPV of US-3 observations for at least probable cancer at diagnostic characterization among high-risk patients, increasing to 1 in 4 among cirrhotic patients from 1 in 25 among non-cirrhotic patients.

  View details for DOI 10.1007/s00261-022-03681-4

  View details for PubMedID 36253490

• Predictive value and prevalence of refractive edge shadow in diagnosis of ovarian dermoids. Abdominal radiology (New York) Shen, L., Tse, J. R., Negrete, L. M., Lo, E., Yoon, L., Kamaya, A. 2022

  Abstract

  To evaluate the diagnostic performance of refractive edge shadow in evaluation of ovarian dermoids compared to other benign adnexal masses.Ultrasound images of 139 patients with 154 dermoids, endometriomas, and hemorrhagic cysts were retrospectively reviewed by 3 radiologists blinded to final diagnosis. Ultrasound and clinical features were compared to pathology or follow-up ultrasound results as reference standard. Inter-reader agreements with free-marginal kappa and diagnostic performance were evaluated. The former was compared using Fisher's exact test or Mann-Whitney test with p < 0.05 to determine statistical significance.The study sample consisted of 154 lesions: 50 dermoids, 50 endometriomas, and 54 hemorrhagic cysts. Refractive edge shadow, homogeneous echogenic appearance, tip of the iceberg sign, mural echogenic nodule, echogenic shadowing focus, and dot-dash sign all were statistically significant across all readers for the diagnosis of dermoid. Prevalence of each feature in dermoids compared to other entities were as follows: refractive edge shadow (70% vs 8%; p < 0.001), homogeneously echogenic appearance (34% vs 2%; p < 0.001), tip of the iceberg sign (16% vs 1%; p < 0.001), mural echogenic nodule (38% vs 2%; p < 0.001), echogenic shadowing focus (13% vs 1%; p < 0.001), and dot-dash sign (44% vs 1%; p < 0.001). Refractive edge shadow had the highest sensitivity, negative predictive value, and accuracy among all ultrasound features associated with dermoids (70%, 86%, and 85%, respectively).Refractive edge shadow is a promising ultrasound feature for diagnosis of dermoids, with the highest diagnostic accuracy and prevalence compared to other previously described features associated with dermoids.

  View details for DOI 10.1007/s00261-022-03666-3

  View details for PubMedID 36098759

• Reply to "Risk Factors and Recommendations for Follow-Up of Gallbladder Polyps". AJR. American journal of roentgenology Walsh, A. J., Bingham, D. B., Kamaya, A. 2022: 1-2

  View details for DOI 10.2214/AJR.22.28051

  View details for PubMedID 36069724

• Proportion of malignancy in Bosniak classification of cystic renal masses version 2019 (v2019) classes: systematic review and meta-analysis. European radiology McGrath, T. A., Bai, X., Kamaya, A., Park, K. J., Park, M. Y., Tse, J. R., Wang, H., McInnes, M. D., Schieda, N. 2022

  Abstract

  Determine the proportion of malignancy within Bosniak v2019 classes.MEDLINE and EMBASE were searched. Eligible studies contained patients with cystic renal masses undergoing CT or MRI renal protocol examinations with pathology confirmation, applying Bosniak v2019. Proportion of malignancy was estimated within Bosniak v2019 class. Risk of bias was assessed using QUADAS-2.We included 471 patients with 480 cystic renal masses. No class I malignant masses were observed. Pooled proportion of malignancy were class II, 12% (6/51, 95% CI 5-24%); class IIF, 46% (37/85, 95% CI 28-66%); class III, 79% (138/173, 95% CI 68-88%); and class IV, 84% (114/135, 95% CI 77-90%). Proportion of malignancy differed between Bosniak v2019 II-IV classes (p = 0.004). Four studies reported the proportion of malignancy by wall/septa feature. The pooled proportion of malignancy with 95% CI were class III thick smooth wall/septa, 77% (41/56, 95% CI 53-91%); class III obtuse protrusion ≤ 3 mm (irregularity), 83% (97/117, 95% CI 75-89%); and class IV nodule with acute angulation, 86% (50/58, 95% CI 75-93%) or obtuse angulation ≥ 4 mm, 83%, (64/77, 95% CI 73-90%). Subgroup analysis by wall/septa feature was limited by sample size; however, no differences were found comparing class III masses with irregularity to class IV masses (p = 0.74) or between class IV masses by acute versus obtuse angles (p = 0.62).Preliminary data suggest Bosniak v2019 class IIF masses have higher proportion of malignancy compared to the original classification, controlling for pathologic reference standard. There are no differences in proportion of malignancy comparing class III masses with irregularities to class IV masses with acute or obtuse nodules.• The proportion of malignancy in Bosniak v2019 class IIF cystic masses is 46% (37 malignant/85 total IIF masses, 95% confidence intervals (CI) 28-66%). • The proportion of malignancy in Bosniak v2019 class III cystic masses is 79% (138/173, 95% CI 68-88%) and in Bosniak v2019 class IV cystic masses is 84% (114/135, 95% CI 77-90%). • Class III cystic masses with irregularities had similar proportion of malignancy (83%, 97/117, 95% CI 75-89%) compared to Bosniak class IV masses (84%, 114/135, 95% CI 77-90%) overall (p = 0.74) with no difference within class IV masses by acute versus obtuse angulation (p = 0.62).

  View details for DOI 10.1007/s00330-022-09102-w

  View details for PubMedID 35999371

• A Comprehensive Motion Compensation Method for In-Plane and Out-of-Plane Motion in Dynamic Contrast-Enhanced Ultrasound of Focal Liver Lesions. Ultrasound in medicine & biology Tiyarattanachai, T., Turco, S., Eisenbrey, J. R., Wessner, C. E., Medellin-Kowalewski, A., Wilson, S., Lyshchik, A., Kamaya, A., Kaffas, A. E. 2022

  Abstract

  Contrast-enhanced ultrasound (CEUS) acquisitions of focal liver lesions are affected by motion, which has an impact on contrast signal quantification. We therefore developed and tested, in a large patient cohort, a motion compensation algorithm called the Iterative Local Search Algorithm (ILSA), which can correct for both periodic and non-periodic in-plane motion and can reject frames with out-of-plane motion. CEUS cines of 183 focal liver lesions in 155 patients from three hospitals were used to develop and test ILSA. Performance was evaluated through quantitative metrics, including the root mean square error and R2 in fitting time-intensity curves and standard deviation value of B-mode intensities, computed across cine frames), and qualitative evaluation, including B-mode mean intensity projection images and parametric perfusion imaging. The median root mean square error significantly decreased from 0.032 to 0.024 (p < 0.001). Median R2 significantly increased from 0.88 to 0.93 (p < 0.001). The median standard deviation value of B-mode intensities significantly decreased from 6.2 to 5.0 (p < 0.001). B-Mode mean intensity projection images revealed improved spatial resolution. Parametric perfusion imaging also exhibited improved spatial detail and better differentiation between lesion and background liver parenchyma. ILSA can compensate for all types of motion encountered during liver CEUS, potentially improving contrast signal quantification of focal liver lesions.

  View details for DOI 10.1016/j.ultrasmedbio.2022.06.007

  View details for PubMedID 35970658

• Improving plane wave ultrasound imaging through real-time beamformation across multiple arrays. Scientific reports Foiret, J., Cai, X., Bendjador, H., Park, E., Kamaya, A., Ferrara, K. W. 2022; 12 (1): 13386

  Abstract

  Ultrasound imaging is a widely used diagnostic tool but has limitations in the imaging of deep lesions or obese patients where the large depth to aperture size ratio (f-number) reduces image quality. Reducing the f-number can improve image quality, and in this work, we combined three commercial arrays to create a large imaging aperture of 100mm and 384 elements. To maintain the frame rate given the large number of elements, plane wave imaging was implemented with all three arrays transmitting a coherent wavefront. On wire targets at a depth of 100mm, the lateral resolution is significantly improved; the lateral resolution was 1.27mm with one array (1/3 of the aperture) and 0.37mm with the full aperture. After creating virtual receiving elements to fill the inter-array gaps, an autoregressive filter reduced the grating lobes originating from the inter-array gaps by -5.2dB. On a calibrated commercial phantom, the extended field-of-view and improved spatial resolution were verified. The large aperture facilitates aberration correction using a singular value decomposition-based beamformer. Finally, after approval of the Stanford Institutional Review Board, the three-array configuration was applied in imaging the liver of a volunteer, validating the potential for enhanced resolution.

  View details for DOI 10.1038/s41598-022-16961-2

  View details for PubMedID 35927389

• Comparative Study of Raw Ultrasound Data Representations in Deep Learning to Classify Hepatic Steatosis. Ultrasound in medicine & biology Sanabria, S. J., Pirmoazen, A. M., Dahl, J., Kamaya, A., El Kaffas, A. 2022

  Abstract

  Adiposity accumulation in the liver is an early-stage indicator of non-alcoholic fatty liver disease. Analysis of ultrasound (US) backscatter echoes from liver parenchyma with deep learning (DL) may offer an affordable alternative for hepatic steatosis staging. The aim of this work was to compare DL classification scores for liver steatosis using different data representations constructed from raw US data. Steatosis in N = 31 patients with confirmed or suspected non-alcoholic fatty liver disease was stratified based on fat-fraction cutoff values using magnetic resonance imaging as a reference standard. US radiofrequency (RF) frames (raw data) and clinical B-mode images were acquired. Intermediate image formation stages were modeled from RF data. Power spectrum representations and phase representations were also calculated. Co-registered patches were used to independently train 1-, 2- and 3-D convolutional neural networks (CNNs), and classifications scores were compared with cross-validation. There were 67,800 patches available for 2-D/3-D classification and 1,830,600 patches for 1-D classification. The results were also compared with radiologist B-mode annotations and quantitative ultrasound (QUS) metrics. Patch classification scores (area under the receiver operating characteristic curve [AUROC]) revealed significant reductions along successive stages of the image formation process (p < 0.001). Patient AUROCs were 0.994 for RF data and 0.938 for clinical B-mode images. For all image formation stages, 2-D CNNs revealed higher patch and patient AUROCs than 1-D CNNs. CNNs trained with power spectrum representations converged faster than those trained with RF data. Phase information, which is usually discarded in the image formation process, provided a patient AUROC of 0.988. DL models trained with RF and power spectrum data (AUROC = 0.998) provided higher scores than conventional QUS metrics and multiparametric combinations thereof (AUROC = 0.986). Radiologist annotations indicated lower hepatic steatosis classification accuracies (Acc = 0.914) with respect to magnetic resonance imaging proton density fat fraction that DL models (Acc = 0.989). Access to raw ultrasound data combined with artificial intelligence techniques may offer superior opportunities for quantitative tissue diagnostics than conventional sonographic images.

  View details for DOI 10.1016/j.ultrasmedbio.2022.05.031

  View details for PubMedID 35914993

• Clinical and ultrasound features of dermoid-associated adnexal torsion. Abdominal radiology (New York) Shen, L., Tse, J. R., Negrete, L. M., Flory, M. N., Yoon, L., Kamaya, A. 2022

  Abstract

  To determine the clinical and ultrasound features of dermoid-associated adnexal torsion.Forty-four patients with at least one dermoid and ultrasound ≤ 30 days of surgery were retrospectively reviewed by three radiologists. Ultrasound and clinical findings were compared to intra-operative findings using Fisher's exact test or Mann-Whitney test with p < 0.05 to determine statistical significance.Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.Correct. No edit RESULTS: Twenty patients had torsion, while 24 patients did not. Patients with dermoid-associated torsion were more likely to present to emergency department (ED) (100% vs 13%; p < 0.001) and have acute unilateral pelvic pain (100% vs 42%; p < 0.001). On ultrasound, patients with torsion had larger dermoids (median largest dimension 9.0 cm (IQR 7.7-11.1) vs 6.0 cm (IQR 4.4-7.5); p < 0.001), displaced dermoid anterior or superior to the uterus (59% vs 21%; p = 0.016), and ipsilateral adnexal fluid (41% vs 4%; p = 0.003). Displaced dermoid and ipsilateral adnexal fluid had substantial (kappa = 0.72) and moderate inter-rater agreement (kappa = 0.49), respectively. The combination of ED presentation and each statistically significant ultrasound feature (dermoid size ≥ 5.0 cm, displaced dermoid, and ipsilateral adnexal fluid) yielded high specificity and positive predictive value (ranging from 93-100% to 92-100%, respectively). The combination of ED presentation and dermoid size ≥ 5.0 cm yielded the highest sensitivity, negative predicative value, and accuracy (100%, 100%, and 96%, respectively).Please check and confirm whether the edit made to the article title is in order.Looks great. No edits. Thank you!Although the diagnosis of adnexal torsion in the presence of an ovarian dermoid is traditionally challenging, the combination of ED presentation and ultrasound features increase diagnostic confidence of dermoid-associated adnexal torsion.

  View details for DOI 10.1007/s00261-022-03601-6

  View details for PubMedID 35809127

• Management of Incidentally Detected Gallbladder Polyps: Society of Radiologists in Ultrasound Consensus Conference Recommendations. Radiology Kamaya, A., Fung, C., Szpakowski, J., Fetzer, D. T., Walsh, A. J., Alimi, Y., Bingham, D. B., Corwin, M. T., Dahiya, N., Gabriel, H., Park, W. G., Porembka, M. R., Rodgers, S. K., Tublin, M. E., Yuan, X., Zhang, Y., Middleton, W. D. 2022: 213079

  Abstract

  Gallbladder polyps (also known as polypoid lesions of the gallbladder) are a common incidental finding. The vast majority of gallbladder polyps smaller than 10 mm are not true neoplastic polyps but are benign cholesterol polyps with no inherent risk of malignancy. In addition, recent studies have shown that the overall risk of gallbladder cancer is not increased in patients with small gallbladder polyps, calling into question the rationale for frequent and prolonged follow-up of these common lesions. In 2021, a Society of Radiologists in Ultrasound, or SRU, consensus conference was convened to provide recommendations for the management of incidentally detected gallbladder polyps at US. See also the editorial by Sidhu and Rafailidis in this issue.

  View details for DOI 10.1148/radiol.213079

  View details for PubMedID 35787200

• Interobserver agreement between eight observers using IOTA simple rules and O-RADS lexicon descriptors for adnexal masses. Abdominal radiology (New York) Antil, N., Raghu, P. R., Shen, L., Tiyarattanachai, T., Chang, E. M., Ferguson, C. W., Ho, A. A., Lutz, A. M., Mariano, A. J., Morimoto, L. N., Kamaya, A. 2022

  Abstract

  PURPOSE: To evaluate interobserver agreement in assigning imaging features and classifying adnexal masses using the IOTA simple rules versus O-RADS lexicon and identify causes of discrepancy.METHODS: Pelvic ultrasound (US) examinations in 114 women with 118 adnexal masses were evaluated by eight radiologists blinded to the final diagnosis (4 attendings and 4 fellows) using IOTA simple rules and O-RADS lexicon. Each feature category was analyzed for interobserver agreement using intraclass correlation coefficient (ICC) for ordinal variables and free marginal kappa for nominal variables. The two-tailed significance level (a) was set at 0.05.RESULTS: For IOTA simple rules, interobserver agreement was almost perfect for three malignant lesion categories (M2-4) and substantial for the remaining two (M1, M5) with k-values of 0.80-0.82 and 0.68-0.69, respectively. Interobserver agreement was almost perfect for two benign feature categories (B2, B3), substantial for two (B4, B5) and moderate for one (B1) with k-values of 0.81-0.90, 0.69-0.70 and 0.60, respectively. For O-RADS, interobserver agreement was almost perfect for two out of ten feature categories (ascites and peritoneal nodules) with k-values of 0.89 and 0.97. Interobserver agreement ranged from fair to substantial for the remaining eight feature categories with k-values of 0.39-0.61. Fellows and attendings had ICC values of 0.725 and 0.517, respectively.CONCLUSION: O-RADS had variable interobserver agreement with overall good agreement. IOTA simple rules had more uniform interobserver agreement with overall excellent agreement. Greater reader experience did not improve interobserver agreement with O-RADS.

  View details for DOI 10.1007/s00261-022-03580-8

  View details for PubMedID 35763052

• Outcomes of LI-RADS US-2 Subthreshold Observations Detected on Surveillance Ultrasound. AJR. American journal of roentgenology Tse, J. R., Shen, L., Bird, K. N., Yoon, L., Kamaya, A. 2022

  Abstract

  Background: Ultrasound LI-RADS version 2017 recommends that patients with US-2 subthreshold observations undergo repeat surveillance ultrasound in 3-6 months and return to routine surveillance if the observation shows no growth for 2 years. However, outcomes of US-2 observations are unknown. Objective: To determine imaging outcomes of US-2 observations detected on surveillance ultrasound examinations. Methods: This retrospective study included 175 patients (median age, 59 years; 70 women, 105 men) at high risk for hepatocellular carcinoma (HCC) with US-2 observations (i.e., subcentimeter observations) on surveillance ultrasound. Observations were classified on ≥2-year follow-up ultrasound as showing no correlate, stable (if remaining subcentimeter), or progressed (if measuring ≥10 mm, meeting US-3 criteria). Observations were classified on follow-up multiphasic CT or MR (stratified as <2-year vs ≥2-year follow-up) as showing no correlate or, if showing a correlate, using CT/MRI LI-RADS version 2018. Results: A total of 111 patients had ≥2-year follow-up ultrasound and 106 had follow-up CT or MRI (79 before 2 years, 27 after 2 years). Based on final follow-up examinations, 173/175 observations were stable on ≥2-year follow-up ultrasound (n=68); showed no correlate on follow-up ultrasound, CT, or MRI (n=88); or were classified as LR-1 or LR-2 on CT or MRI (n=17). The remaining 2/175 observations were LR-3 on CT or MRI. No observations progressed to US-3 on follow-up ultrasound or were classified as ≥LR-4 on CT or MRI. A correlate was observed in 25 of the 106 follow-up CT or MRI examinations, (LR-1 or LR-2 in 23; LR-3 in 2). Eight patients developed HCC at a median of 2.0 years after initial US-2 observation detection; all HCCs were in separate locations from the baseline observations and were preceded by a surveillance ultrasound that could not re-identify the baseline observation. In three patients who underwent liver transplant, the explant showed no dysplastic nodule or HCC. Conclusion: US-2 subthreshold observations are unlikely to progress or become HCC and commonly have no correlate on follow-up imaging. Clinical Impact: Because of the low progression rate of US-2 subthreshold observations, it is unclear if an extended period of intensive surveillance, as recommended by multiple professional societies, is warranted.

  View details for DOI 10.2214/AJR.22.27812

  View details for PubMedID 35703411

• Nyquist sampling theorem and Bosniak classification, version 2019: effect of thin axial sections on categorization and agreement. European radiology Tse, J. R., Shen, L., Shen, J., Yoon, L., Kamaya, A. 2022

  Abstract

  To determine if CT axial images reconstructed at current standard of care (SOC; 2.5-3 mm) or thin (≤ 1 mm) sections affect categorization and inter-rater agreement of cystic renal masses assessed with Bosniak classification, version 2019.In this retrospective single-center study, 3 abdominal radiologists reviewed 131 consecutive cystic renal masses from 100 patients performed with CT renal mass protocol from 2015 to 2021. Images were reviewed in two sessions: first with SOC and then the addition of thin sections. Individual and overall categorizations are reported, latter of which is based on majority opinion with 3-way discrepancies resolved by a fourth reader. Major categorization changes were defined as differences between classes I-II, IIF, or III-IV.Thin sections led to a statistically significant major category change with class II for all readers individually (p = 0.004-0.041; McNemar test), upgrading 10-17% of class II masses, most commonly to class IIF followed by III. Modal reason for upgrades was due to identification of additional septa followed by larger measurement of enhancing features. Masses categorized as class I, III, or IV on SOC sections were unaffected, as were identification of protrusions. Inter-rater agreements using weighted Cohen's kappa were 0.679 for SOC and 0.691 for thin sections (both substantial).Thin axial sections upgraded up to one in six class II masses to IIF or III through identification of additional septa or larger feature. Other classes, including III-IV, were unaffected. Inter-rater agreements were substantial regardless of section thickness.• Thin axial sections (≤ 1 mm) compared to standard of care sections (2.5-3 mm) led to identification of additional septa but did not affect identification of protrusions. • Thin axial sections (≤ 1 mm) compared to standard of care sections (2.5-3 mm) can upgrade a small proportion of cystic renal masses from class II to IIF or III when applying Bosniak classification, version 2019. • Inter-rater agreements were substantial regardless of section thickness.

  View details for DOI 10.1007/s00330-022-08876-3

  View details for PubMedID 35705828

• Patient-Friendly Summary of the ACR Appropriateness Criteria Crohn Disease-Child. Journal of the American College of Radiology : JACR Guernsey, E. K., Kamaya, A. 2022

  View details for DOI 10.1016/j.jacr.2022.05.010

  View details for PubMedID 35710770

• Diagnostic Performance of the Ovarian-Adnexal Reporting and Data System (O-RADS) Ultrasound Risk Score in Women in the United States. JAMA network open Jha, P., Gupta, A., Baran, T. M., Maturen, K. E., Patel-Lippmann, K., Zafar, H. M., Kamaya, A., Antil, N., Barroilhet, L., Sadowski, E. A. 2022; 5 (6): e2216370

  Abstract

  The American College of Radiology (ACR) Ovarian-Adnexal Reporting and Data System (O-RADS) ultrasound (US) risk scoring system has been studied in a selected population of women referred for suspected or known adnexal lesions. This population has a higher frequency of malignant neoplasms than women presenting to radiology departments for pelvic ultrasonography for a variety of indications, potentially impacting the diagnostic performance of the risk scoring system.To evaluate the risk of malignant neoplasm and diagnostic performance of O-RADS US risk scoring system in a multi-institutional, nonselected cohort.This multi-institutional cohort study included a population of nonselected women in the United States who presented to radiology departments for routine pelvic ultrasonography between 2011 and 2014, with pathology confirmation imaging follow up or 2 years of clinical follow up.Analysis of 1014 adnexal lesions using the O-RADS US risk stratification system.Frequency of ovarian cancer and diagnostic performance of the O-RADS US risk stratification system.This study included 913 women with 1014 adnexal lesions. The mean (SD) age of the patients was 42.4 (13.9 years), and 674 of 913 (73.8%) were premenopausal. The overall frequency of malignant neoplasm was 8.4% (85 of 1014 adnexal lesions). The frequency of malignant neoplasm for O-RADS US 2 was 0.5% (3 of 657 lesions; <1% expected); O-RADS US 3, 4.5% (5 of 112 lesions; <10% expected); O-RADS US 4, 11.6% (18 of 155; 10%-50% expected); and O-RADS 5, 65.6% (59 of 90 lesions; >50% expected). O-RADS US 4 was the optimum cutoff for diagnosing cancer with sensitivity of 90.6% (95% CI, 82.3%-95.9%), specificity of 81.9% (95% CI, 79.3%-84.3%), positive predictive value of 31.4% (95% CI, 25.7%-37.7%) and negative predictive value of 99.0% (95% CI, 98.0%-99.6%).In this cohort study of a nonselected patient population, the O-RADS US risk stratification system performed within the expected range as published by the ACR O-RADS US committee. The frequency of malignant neoplasm was at the lower end of the published range, partially because of the lower prevalence of cancer in a nonselected population. However, a high negative predictive value was maintained, and when a lesion can be classified as an O-RADS US 2, the risk of cancer is low, which is reassuring for both clinician and patient.

  View details for DOI 10.1001/jamanetworkopen.2022.16370

  View details for PubMedID 35679042

• Acing the Fundamentals of Radiology: An Online Series for Medical Students and Interns. Journal of computer assisted tomography Kamel, S., Wang, M. X., Ghannam, S., Gopal, A., Baqai, F., Rohren, S., Patel, P., Khan, Z., Aly, M., Reiter, A. M., Zook, S., Udayakumar, N., Kumaraval, M., Kamaya, A., Jambhekar, K., Elsamaloty, H., Gaballah, A., Stein, L., Abdelsalam, M., Chernyak, V., Elsayes, K. M. 2022

  Abstract

  PURPOSE: The current undergraduate radiology education predominantly integrates radiology with other disciplines during preclerkship years and is often taught by nonradiologists. Early exposure to radiology and profound understanding of scientific fundamentals of imaging modalities and techniques are essential for a better understanding and interest in the specialty. Furthermore, the COVID-19 pandemic-related impact on in-person medical education aggravated the need for alternative virtual teaching initiatives to provide essential knowledge to medical students.METHODS: The authors designed an online 7-session course on the principles of imaging modalities for medical students and fresh graduates in the United States and abroad. The course was delivered online and taught by radiologists from different US institutions. Pretests and posttests were delivered before and after each session, respectively, to assess change in knowledge. At the end of the course, a survey was distributed among students to collect their assessment and feedback.RESULTS: A total of 162 students and interns initially enrolled in the program by completing a sign-up interest form. An average of 65 participants attended each live session, with the highest attendance being 93 live attendees. An average of 44 attendees completed both the pretest and posttest for each session. There was a statistically significant increase in posttest scores compared with pretest scores (P < 0.01) for each session; on average, the posttest scores were 48% higher than the pretest scores. A total of 84 participants answered the end-of-course survey. A total of 11% of the respondents described themselves as first year, 17% as second year, 18% as third year, 21% as fourth year, and 33% as "other." Attendees were enrolled in medical schools across 21 different countries with 35% of the respondents studying medicine in the United States. More than 76% of the respondents stated that they "strongly agree" that the program increased their understanding of radiology, increased their interest in radiology, and would be useful in their clinical practice in the future. Eighty-three percent of the respondents stated that they "strongly agree" that "this course was a worthwhile experience." Particularly, more than 84% of the respondents stated that among the most important components in enhancing their understanding of radiology were "the interpretation of normal imaging" and "interpretation of clinical cases." Ninety-two percent of the respondents stated that "the amount of effort to complete the requirements for this program was just right." Participants were also asked to rate each of the 8 sessions using the following scale: poor = 1 point, fair = 2, good = 3, and excellent = 4. The average rating for all 8 sessions was 3.61 points (SD = 0.55), which translates to 96% of the sessions being rated good or excellent. Eighty percent of the participants reported that the topics presented in the program were "excellent and clinically important to learn," and 20% of the participants reported that the topics presented were "good and somewhat important to learn." The participants were asked to evaluate their confidence regarding basic radiology skills before and after the program using the following scale: not confident at all = 1 point, somewhat confident = 2, moderately confident = 3, and very confident = 4. Figure 2 summarizes the responses of the participants.CONCLUSIONS: An online course to teach the fundamentals of imaging modalities could be delivered through a webinar format to medical students and interns in several countries to address the potential gaps in radiology education, therefore increasing their understanding of the different imaging modalities and their proper use in medicine.

  View details for DOI 10.1097/RCT.0000000000001306

  View details for PubMedID 35405708

• Liver imaging: it is time to adopt standardized terminology. European radiology Chernyak, V., Tang, A., Do, R. K., Kamaya, A., Kono, Y., Santillan, C. S., Fowler, K. J., Bashir, M. R., Cunha, G. M., Fetzer, D. T., Kielar, A., Lee, J. T., Mendiratta-Lalla, M., Sirlin, C. B., and the LI-RADS Steering Committee and Guarantors of translation integrity listed in the Acknowledgements 2022

  Abstract

  Liver imaging plays a vital role in the management of patients at risk for hepatocellular carcinoma (HCC); however, progress in the field is challenged by nonuniform and inconsistent terminology in the published literature. The Steering Committee of the American College of Radiology (ACR)'s Liver Imaging Reporting And Data System (LI-RADS), in conjunction with the LI-RADS Lexicon Writing Group and the LI-RADS International Working Group, present this consensus document to establish a single universal liver imaging lexicon. The lexicon is intended for use in research, education, and clinical care of patients at risk for HCC (i.e., the LI-RADS population) and in the general population (i.e., even when LI-RADS algorithms are not applicable). We anticipate that the universal adoption of this lexicon will provide research, educational, and clinical benefits. KEY POINTS: To standardize terminology, we encourage authors of research and educational materials on liver imaging to use the standardized LI-RADS Lexicon. We encourage reviewers to promote the use of the standardized LI-RADS Lexicon for publications on liver imaging. We encourage radiologists to use the standardized LI-RADS Lexicon for liver imaging in clinical care.

  View details for DOI 10.1007/s00330-022-08769-5

  View details for PubMedID 35389052

• Multicenter Study of ACR Ultrasound LI-RADS Visualization Scores on Serial Examinations: Implications for Changes in Surveillance Strategies. AJR. American journal of roentgenology Tiyarattanachai, T., Fetzer, D. T., Kamaya, A. 2022

  Abstract

  Background: American College of Radiology Ultrasound LI-RADS includes the visualization score as a subjective measure of examination quality and expected level of sensitivity. Whether a single suboptimal visualization score warrants change in surveillance strategy is unknown. Objective: To determine the relative stability of visualization scores on serial surveillance ultrasound examinations in patients at risk for HCC. Methods: This retrospective study included patients at risk for HCC who underwent at least two HCC surveillance ultrasound examinations at one of three institutions between January 2017 and November 2020. Frequencies of score remaining unchanged after variable numbers of preceding examinations with the given score were determined. A mixed-effects logistic model was fitted to identify factors associated with a repeat score C (severe limitations) versus change to score A (no or minimal limitations) or score B (moderate limitations). Results: A total of 3169 patients underwent at least 2 ultrasound examinations, yielding a total of 9602 examinations. A total of 8030 (83.6%) examinations had score A, 1378 (14.4%) score B, and 194 (2.0%) score C. Frequency of score A was 88%, 91%, and 93% after 1, 2 and 3 consecutive prior examinations with score A. Frequency of score B was 45%, 48%, and 55% after 1, 2, and 3 consecutive prior examinations with score B. Frequency of score C was 42%, 67%, and 80% after 1, 2, and 3 consecutive prior examinations with score C. Among 109 examinations with score C in 91 patients with an available follow-up examination, no factor (including age, sex, severe steatosis, advanced cirrhosis, ascites, body mass index, and change in ultrasound machine, sonographer, or radiologist) was significantly associated with repeat score C (all p>.05). Although not statistically significant, presence of severe steatosis and advanced cirrhosis had the highest odds ratios (2.88 and 2.38, respectively) for repeat score C in multivariable analysis. Conclusion: Only 42% of patients with visualization score C on surveillances examination have score C on follow-up examination. Clinical Impact: The findings may inform decisions for alternative surveillance strategies in patients with visualization score C on ultrasound. This decision should consider the number of previous examinations with score C.

  View details for DOI 10.2214/AJR.22.27405

  View details for PubMedID 35383486

• Interpretable machine learning for characterization of focal liver lesions by contrast-enhanced ultrasound. IEEE transactions on ultrasonics, ferroelectrics, and frequency control Turco, S., Tiyarattanachai, T., Ebrahimkheil, K., Eisenbrey, J., Kamaya, A., Mischi, M., Lyshchik, A., El Kaffas, A. 2022; PP

  Abstract

  This work proposes an interpretable radiomics approach to differentiate between malignant and benign focal liver lesions (FLLs) on contrast-enhanced ultrasound (CEUS). Although CEUS has shown promise for differential FLLs diagnosis, current clinical assessment is performed only by qualitative analysis of the contrast enhancement patterns. Quantitative analysis is often hampered by the unavoidable presence of motion artefacts and by the complex, spatiotemporal nature of liver contrast enhancement, consisting of multiple, overlapping vascular phases. To fully exploit the wealth of information in CEUS, while coping with these challenges, here we propose to combine features extracted by temporal and spatiotemporal analysis in the arterial phase enhancement with spatial features extracted by texture analysis at different time points. Using the extracted features as input, several machine learning classifier are optimized to achieve semi-automatic FLLs characterization, for which there is no need for motion compensation and the only manual input required is the location of a suspicious lesion. Clinical validation on 87 FLLs from 72 patients at risk for HCC showed promising performance, achieving a balanced accuracy of 0.84 in the distinction between benign and malignant lesions. Analysis of feature relevance demonstrates that a combination of spatiotemporal and texture features is needed to achieve the best performance. Interpretation of the most relevant features suggests that aspects related to microvascular perfusion and the microvascular architecture, together with the spatial enhancement characteristics at wash-in and peak enhancement, are important to aid the accurate characterization of FLLs.

  View details for DOI 10.1109/TUFFC.2022.3161719

  View details for PubMedID 35320099

• Patient-Friendly Summary of the ACR Appropriateness Criteria Sinonasal Disease: 2021 Update. Journal of the American College of Radiology : JACR Kotsis, S. V., Kamaya, A. 2022

  View details for DOI 10.1016/j.jacr.2022.02.004

  View details for PubMedID 35307302

• Survey Study on the Experience, Practice Patterns, and Preferences of the Fellows of the Society of Radiologists in Ultrasound for Evaluation and Management of Gallbladder Polyps Detected With Ultrasound. Ultrasound quarterly Middleton, W. D., Fung, C., Dahiya, N., Szpakowski, J., Corwin, M. T., Fetzer, D. T., Gabriel, H., Rodgers, S. K., Tublin, M. E., Walsh, A. J., Kamaya, A. 2022

  Abstract

  ABSTRACT: Gallbladder polyps (GPs) are a common incidental finding on ultrasound; however, important differences in recommended management exist among professional society guidelines.An electronic survey was sent to 189 fellows of the Society of Radiologists in Ultrasound. Main outcomes included preferences and current practice patterns for evaluation, management, and surveillance of GPs as well as personal lifetime experience with gallbladder sonography and GPs.A total of 64 subjects (34%) with experience in gallbladder sonography completed the study. The estimated combined total number of gallbladder scans seen by the responders was 3,071,880. None of fellows had ever seen a pedunculated GP <1 cm detected on ultrasound that was proven to be malignant at the time of detection or during subsequent follow-up. All of the fellows used size as a feature to stratify recommendations. The median size threshold currently used by Society of Radiologists in Ultrasound fellows for recommending ultrasound follow-up was 6 mm, and their preferred threshold was 7 mm. The median size threshold for recommending surgical consultation was 10 mm, and the preferred threshold was 10 mm. Wall thickening and shape were considered important factors by 76% and 67% of respondents, respectively.Society of Radiologists in Ultrasound fellows tend to provide recommendations most similar to the American College of Radiology and Canadian Association of Radiology guidelines for management of GPs. Many would prefer guidelines that result in fewer recommendations for follow-up and surgical consultation. Despite a substantial combined experience, this survey did not uncover any case of a small GP that was malignant.

  View details for DOI 10.1097/RUQ.0000000000000597

  View details for PubMedID 35221317

• Growth kinetics and progression rates of cystic renal masses on active surveillance. Tse, J., Shen, L., Yoon, L., Kamaya, A. LIPPINCOTT WILLIAMS & WILKINS. 2022

  View details for DOI 10.1200/JCO.2022.40.6_suppl.298

  View details for Web of Science ID 000771008900303

• Patient-Friendly Summary of the ACR Appropriateness Criteria Transgender Breast Cancer Screening. Journal of the American College of Radiology : JACR Lockhart, R., Kamaya, A. 1800

  View details for DOI 10.1016/j.jacr.2021.10.015

  View details for PubMedID 35090835

• Evaluation of early sonographic predictors of gangrenous cholecystitis: mucosal discontinuity and echogenic pericholecystic fat. Abdominal radiology (New York) Tse, J. R., Gologorsky, R., Shen, L., Bingham, D. B., Jeffrey, R. B., Kamaya, A. 1800

  Abstract

  PURPOSE: To identify early sonographic features of gangrenous cholecystitis.MATERIALS AND METHODS: 101 patients with acute cholecystitis and a pre-operative sonogram were retrospectively reviewed by three radiologists in this IRB-approved and HIPAA-compliant study. Imaging data were correlated with histologic findings and compared using the Fisher's exact test or Student t test with p<0.05 to determine statistical significance.RESULTS: Forty-eight patients had gangrenous cholecystitis and 53 had non-gangrenous acute cholecystitis. Patients with gangrenous cholecystitis tended to be older (67±17 vs 48±18years; p=0.0001), male (ratio of male:female 2:1 vs 0.6:1; p=0.005), tachycardic (60% vs 28%; p=0.001), and diabetic (25% vs 8%; p=0.001). Median time between pre-operative sonogram and surgery was 1day. On imaging, patients with gangrenous cholecystitis were more likely to have echogenic pericholecystic fat (p=0.001), mucosal discontinuity (p=0.010), and frank perforation (p=0.004), while no statistically significant differences were seen in the presence of sloughed mucosa (p=0.104), pericholecystic fluid (p=0.523) or wall striations (p=0.839). In patients with gangrenous cholecystitis and echogenic pericholecystic fat, a smaller subset had concurrent mucosal discontinuity (57%), and a smaller subset of those had concurrent frank perforation (58%). The positive likelihood ratios for gangrenous cholecystitis with echogenic fat and mucosal discontinuity were 4.6 (95% confidence interval 1.9-11.3) and 14.4 (2.0-106), respectively.CONCLUSION: Echogenic pericholecystic fat and mucosal discontinuity are early sonographic findings that may help identify gangrenous cholecystitis prior to late findings of frank perforation.

  View details for DOI 10.1007/s00261-021-03320-4

  View details for PubMedID 34985635

• Ovarian Cancer Detection in Average-Risk Women: Classic- versus Nonclassic-appearing Adnexal Lesions at US. Radiology Gupta, A., Jha, P., Baran, T. M., Maturen, K. E., Patel-Lippmann, K., Zafar, H. M., Kamaya, A., Antil, N., Barroilhet, L., Sadowski, E. 2022: 212338

  Abstract

  Background Several US risk stratification schemas for assessing adnexal lesions exist. These multiple-subcategory systems may be more multifaceted than necessary for isolated adnexal lesions in average-risk women. Purpose To explore whether a US-based classification scheme of classic versus nonclassic appearance can be used to help appropriately triage women at average risk of ovarian cancer without compromising diagnostic performance. Materials and Methods This retrospective multicenter study included isolated ovarian lesions identified at pelvic US performed between January 2011 and June 2014, reviewed between September 2019 and September 2020. Lesions were considered isolated in the absence of ascites or peritoneal implants. Lesions were classified as classic or nonclassic based on sonographic appearance. Classic lesions included simple cysts, hemorrhagic cysts, endometriomas, and dermoids. Otherwise, lesions were considered nonclassic. Outcomes based on histopathologic results or clinical or imaging follow-up were recorded. Diagnostic performance and frequency of malignancy were calculated. Frequency of malignancy between age groups was compared using the χ2 test, and Poisson regression was used to explore relationships between imaging features and malignancy. Results A total of 970 isolated lesions in 878 women (mean age, 42 years ± 14 [SD]) were included. The malignancy rate for classic lesions was less than 1%. Of 970 lesions, 53 (6%) were malignant. The malignancy rate for nonclassic lesions was 32% (33 of 103) when blood flow was present and 8% (16 of 194) without blood flow (P < .001). For women older than 60 years, the malignancy rate was 50% (10 of 20 lesions) when blood flow was present and 13% (five of 38) without blood flow (P = .004). The sensitivity, specificity, positive predictive value, and negative predictive value of the classic-versus-nonclassic schema was 93% (49 of 53 lesions), 73% (669 of 917 lesions), 17% (49 of 297 lesions), and 99% (669 of 673 lesions), respectively, for detection of malignancy. Conclusion Using a US classification schema of classic- or nonclassic-appearing adnexal lesions resulted in high sensitivity and specificity in the diagnosis of malignancy in ovarian cancer. The highest risk of cancer was in isolated nonclassic lesions with blood flow in women older than 60 years. © RSNA, 2022 See also the editorial by Baumgarten in this issue.

  View details for DOI 10.1148/radiol.212338

  View details for PubMedID 35315722

• Colonoscopy Versus Catheter Angiography for Lower Gastrointestinal Bleeding After Localization on CT Angiography. Journal of the American College of Radiology : JACR Tse, J. R., Felker, E. R., Tse, G. G., Liang, T., Shen, J., Kamaya, A. 2022

  Abstract

  The aim of this study was to compare catheter angiography (CA) and colonoscopy outcomes after successful CT angiographic (CTA) localization for patients with overt lower gastrointestinal bleeding (LGIB).Seventy-one consecutive patients from two institutions between 2010 and 2020 had both contrast extravasation on CTA imaging in the lower gastrointestinal tract and subsequent CA or colonoscopy. The primary outcome was confirmation of active bleeding during CA or colonoscopy (defined as confirmation yield). The secondary outcomes were to determine therapeutic yield (hemostatic therapy), time to procedure, rebleeding rate, and adverse outcome rates (defined as surgery, acute kidney injury, initiation of dialysis, and overall mortality). Univariate analyses and multivariable analyses with P < .05 were used to determine statistical significance.Forty-four patients underwent CA and 27 underwent colonoscopy. CA had higher overall confirmation yield (55% vs 26%, P = .026), while therapeutic yields were similar (70% vs 56%, P = .214). Time to procedure was 5.1 ± 3.4 hours for CA and 15.5 ± 13.6 hours for colonoscopy (P < .0001). On multivariable analysis, shorter time to procedure was the only statistically significant predictor of confirmation yield (P = .037) and therapeutic yield (P = .013), while procedure, hemoglobin, transfusions, and hemodynamic instability were not. Adverse events and rebleeding were not statistically different between patients who underwent CA and colonoscopy (P > .05).Shorter time to procedure was the only statistically significant predictor of confirmation and therapeutic yield after CTA localization of LGIB. Because CA can be performed sooner than colonoscopy without increased rates of adverse outcomes or rebleeding, CA may be a reasonable first-line treatment option in patients with CTA localization of LGIB.

  View details for DOI 10.1016/j.jacr.2022.01.010

  View details for PubMedID 35240106

• Color Doppler Imaging of Vascular Abnormalities of the Uterus Ultrasound Quarterly. Keller, C. A., Antil, N., Jeffrey, B., Kamaya, A. 2022; 38 (1): 72-82

  View details for DOI 10.1097/RUQ.0000000000000578

• Growth Kinetics and Progression Rate of Bosniak Classification, Version 2019 III and IV Cystic Renal Masses on Imaging Surveillance. AJR. American journal of roentgenology Tse, J. R., Shen, L., Shen, J., Yoon, L., Chung, B. I., Kamaya, A. 2022

  Abstract

  Background: Active surveillance is increasingly used as first-line management for localized renal masses. Triggers for intervention primarily reflect growth kinetics, which are poorly investigated for cystic masses defined by Bosniak classification version 2019 (v2019). Objective: To determine growth kinetics and incidence rates of progression of class III and IV cystic renal masses, as defined by Bosniak classification v2019. Methods: This retrospective study included 105 patients (68 men, 37 women; median age, 67 years) with 112 Bosniak v2019 class III or IV cystic renal masses on baseline renal-mass protocol CT or MRI examinations from January 2005 to September 2021. Mass dimensions were measured. Progression was defined as any of: linear growth rate (LGR) ≥5 mm per year (representing clinical guideline threshold for intervention), volume doubling time <1 year, T category increase, or N1 or M1 disease. Class III and IV masses were compared. Time-to-progression was estimated using Kaplan-Meier curve analysis. Results: At baseline, 58 masses were class III and 54 were class IV. Median follow-up was 406 days. Median LGR was for class III masses 0.0 mm per year [interquartile range (IQR) -1.3 to 1.8] and for class IV masses 2.3 mm per year (IQR 0.0¬¬-5.7) (p<.001). LGR exceeded 5 mm per year in 4 (7%) class 3 masses and 15 (28%) class IV masses (p=.005). Two patients, both with class IV masses, developed distant metastases. Incidence rate of progression was for class III masses 11.0 (95% CI 4.5-22.8) and for class IV masses 73.6 (95% CI 47.8-108.7) per 100,000 person-days of follow-up. Median time-to-progression was undefined for class III mases given small number of progression events and 710 days for class IV masses. Hazard ratio of progression for class IV relative to class III masses was 5.1 (95% CI 2.5-10.8) (p<.001). Conclusion: During active surveillance of cystic masses evaluated using Bosniak classification v2019, class IV masses grew faster and were more likely to progress than class III masses. Clinical Impact: In comparison with current active surveillance guidelines that treat class III and IV masses similarly, future iterations may incorporate relatively more intensive surveillance for class IV masses.

  View details for DOI 10.2214/AJR.22.27400

  View details for PubMedID 35293234

• ACR Appropriateness Criteria Epigastric Pain. Journal of the American College of Radiology : JACR Expert Panel on Gastrointestinal Imaging, Vij, A., Zaheer, A., Kamel, I. R., Porter, K. K., Arif-Tiwari, H., Bashir, M. R., Fung, A., Goldstein, A., Herr, K. D., Kamaya, A., Kobi, M., Landler, M. P., Russo, G. K., Thakrar, K. H., Turturro, M. A., Wahab, S. A., Wardrop, R. M., Wright, C. L., Yang, X., Carucci, L. R. 2021; 18 (11S): S330-S339

  Abstract

  Epigastric pain can have multiple etiologies including myocardial infarction, pancreatitis, acute aortic syndromes, gastroesophageal reflux disease, esophagitis, peptic ulcer disease, gastritis, duodenal ulcer disease, gastric cancer, and hiatal hernia. This document focuses on the scenarios in which epigastric pain is accompanied by symptoms such as heartburn, regurgitation, dysphagia, nausea, vomiting, and hematemesis, which raise suspicion for gastroesophageal reflux disease, esophagitis, peptic ulcer disease, gastritis, duodenal ulcer disease, gastric cancer, or hiatal hernia. Although endoscopy may be the test of choice for diagnosing these entities, patients may present with nonspecific or overlapping symptoms, necessitating the use of imaging prior to or instead of endoscopy. The utility of fluoroscopic imaging, CT, MRI, and FDG-PET for these indications are discussed. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

  View details for DOI 10.1016/j.jacr.2021.08.006

  View details for PubMedID 34794592

• Role of Ultrasound for Chronic Liver Disease and Hepatocellular Carcinoma Surveillance. Magnetic resonance imaging clinics of North America Choi, H. H., Rodgers, S. K., Khurana, A., Nelson, L. W., Kamaya, A. 2021; 29 (3): 279-290

  Abstract

  Ultrasound plays a vital role in the evaluation of patients with chronic liver disease and in hepatocellular carcinoma (HCC) surveillance in populations at risk for developing HCC. Semiannual ultrasound for HCC surveillance is universally recommended by all liver societies around the world. Advanced ultrasound techniques, such as elastography and contrast-enhanced ultrasound, offer additional benefits in imaging evaluation of chronic liver disease. Major benefits of ultrasound include its high safety profile and relatively low cost.

  View details for DOI 10.1016/j.mric.2021.05.005

  View details for PubMedID 34243917

• Ultrasound Liver Imaging Reporting and Data System (US LI-RADS) Visualization Score: a reliability analysis on inter-reader agreement. Abdominal radiology (New York) Tiyarattanachai, T., Bird, K. N., Lo, E. C., Mariano, A. T., Ho, A. A., Ferguson, C. W., Chima, R. S., Desser, T. S., Morimoto, L. N., Kamaya, A. 2021

  Abstract

  BACKGROUND & AIM: The American College of Radiology Ultrasound Liver Imaging Reporting and Data System (ACR US LI-RADS) Visualization Score conveys the expected level of sensitivity of screening and surveillance ultrasound exams in patients at risk for hepatocellular carcinoma (HCC). We sought to determine inter-reader agreement of the Visualization Score which is currently unknown.METHODS: Consecutive 6998 ultrasound HCC screening and surveillance studies in 3115 patients from 2017 to 2020 were retrospectively retrieved. Of these, 6154 (87.9%) studies were Visualization A (No or minimal limitations), 709 (10.1%) were Visualization B (Moderate limitations), and 135 (1.9%) were Visualization C (Severe limitations). Randomly sampled 90 studies, with 30 studies in each Visualization category, were included for analysis. Nine radiologists (3 senior attendings, 3 junior attendings and 3 body imaging fellows) blinded to the original categorization independently reviewed each study and assigned a Visualization Score. Intraclass correlation coefficient (ICC) was used to quantify inter-reader agreement.RESULTS: ICC among all 9 radiologists was 0.70 (95% CI 0.63-0.77). ICCs among senior attendings, junior attendings and body imaging fellows were 0.68 (CI 0.58-0.76), 0.72 (CI 0.62-0.80) and 0.76 (CI 0.68-0.83), respectively. Subgroup analysis by liver parenchyma was further performed. ICC was highest in the patient group with normal liver parenchyma (0.69, CI 0.56-0.81), followed by steatosis (0.66, CI 0.54-0.79) and cirrhosis (0.58, CI 0.43-0.73), respectively.CONCLUSIONS: US LI-RADS Visualization Score is a reliable tool with good inter-reader agreement that can be used to indicate the expected level of sensitivity of a screening and surveillance ultrasound examination for detecting focal liver observations.

  View details for DOI 10.1007/s00261-021-03067-y

  View details for PubMedID 34228197

• Extravasation Volume at Computed Tomography Angiography Correlates With Bleeding Rate and Prognosis in Patients With Overt Gastrointestinal Bleeding. Investigative radiology Tse, J. R., Shen, J. n., Shah, R. n., Fleischmann, D. n., Kamaya, A. n. 2021

  Abstract

  Despite the identification of active extravasation on computed tomography angiography (CTA) in patients with overt gastrointestinal bleeding (GIB), a large proportion do not have active bleeding or require hemostatic therapy at endoscopy, catheter angiography, or surgery. The objective of our proof-of-concept study was to improve triage of patients with GIB by correlating extravasation volume of first-pass CTA with bleeding rate and clinical outcomes.All patients who presented with overt GIB and active extravasation on CTA from January 2014 to July 2019 were reviewed in this retrospective, institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study. Extravasation volume was assessed using 3-dimensional software and correlated with hemostatic therapy (primary endpoint) and with intraprocedural bleeding, blood transfusions, and mortality as secondary endpoints using logistic regression models (P < 0.0125 indicating statistical significance). Odds ratios were used to determine the effect size of a threshold extravasation volume. Quantitative data (extravasation volume, aorta attenuation, extravasation attenuation and time) were input into a mathematical model to calculate bleeding rate.Fifty consecutive patients including 6 (12%) upper, 18 (36%) small bowel, and 26 (52%) lower GIB met inclusion criteria. Forty-two underwent catheter angiography, endoscopy, or surgery; 16 had intraprocedural active bleeding, and 24 required hemostatic therapy. Higher extravasation volumes correlated with hemostatic therapy (P = 0.007), intraprocedural active bleeding (P = 0.003), and massive transfusion (P = 0.0001), but not mortality (P = 0.936). Using a threshold volume of 0.80 mL or greater, the odds ratio of hemostatic therapy was 8.1 (95% confidence interval, 2.1-26), active bleeding was 11.8 (2.6-45), and massive transfusion was 18 (2.3-65). With mathematical modeling, extravasation volume had a direct and linear relationship with bleeding rate, and the lowest calculated detectable bleeding rate with CTA was less than 0.1 mL/min.Larger extravasation volumes correlate with higher bleeding rates and may identify patients who require hemostatic therapy, have intraprocedural bleeding, and require blood transfusions. Current CTAs can detect bleeding rates less than 0.1 mL/min.

  View details for DOI 10.1097/RLI.0000000000000753

  View details for PubMedID 33449577

• Diagnostic Performance of 9 Quantitative Ultrasound Parameters for Detection and Classification of Hepatic Steatosis in Nonalcoholic Fatty Liver Disease. Investigative radiology Pirmoazen, A. M., Khurana, A., Loening, A. M., Liang, T., Shamdasani, V., Xie, H., El Kaffas, A., Kamaya, A. 2021

  Abstract

  Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease worldwide. Quantitative ultrasound (QUS) parameters based on radiofrequency raw data show promise in quantifying liver fat.The aim of this study was to evaluate the diagnostic performance of 9 QUS parameters compared with magnetic resonance imaging (MRI)-estimated proton density fat fraction (PDFF) in detecting and staging hepatic steatosis in patients with or suspected of NAFLD.In this Health Insurance Portability and Accountability Act-compliant institutional review board-approved prospective study, 31 participants with or suspected of NAFLD, without other underlying chronic liver diseases (13 men, 18 women; average age, 52 years [range, 26-90 years]), were examined. The following parameters were obtained: acoustic attenuation coefficient (AC); hepatorenal index (HRI); Nakagami parameter; shear wave elastography measures such as shear wave elasticity, viscosity, and dispersion; and spectroscopy-derived parameters including spectral intercept (SI), spectral slope (SS), and midband fit (MBF). The diagnostic ability (area under the receiver operating characteristic curves and accuracy) of QUS parameters was assessed against different MRI-PDFF cutoffs (the reference standard): 6.4%, 17.4%, and 22.1%. Linearity with MRI-PDFF was evaluated with Spearman correlation coefficients (p).The AC, SI, Nakagami, SS, HRI, and MBF strongly correlated with MRI-PDFF (P = 0.89, 0.89, 0.88, -0.87, 0.81, and 0.71, respectively [P < 0.01]), with highest area under the receiver operating characteristic curves (ranging from 0.85 to 1) for identifying hepatic steatosis using 6.4%, 17.4%, and 22.1% MRI-PDFF cutoffs. In contrast, shear wave elasticity, shear wave viscosity, and shear wave dispersion did not strongly correlate to MRI-PDFF (P = 0.45, 0.38, and 0.07, respectively) and had poor diagnostic performance.The AC, Nakagami, SI, SS, MBF, and HRI best correlate with MRI-PDFF and show high diagnostic performance for detecting and classifying hepatic steatosis in our study population.Quantitative ultrasound is an accurate alternative to MRI-based techniques for evaluating hepatic steatosis in patients with or at risk of NAFLD.Our preliminary results show that specific quantitative ultrasound parameters accurately detect different degrees of hepatic steatosis in NAFLD.

  View details for DOI 10.1097/RLI.0000000000000797

  View details for PubMedID 34049335

• Diagnostic Ultrasound Abdomen and Pelvis, Second Edition Kamaya , A., Wong-You-Cheong , J. Elsevier . 2021
• Cystic artery velocity as a predictor of acute cholecystitis. Abdominal radiology (New York) Perez, M. G., Tse, J. R., Bird, K. N., Liang, T., Brooke Jeffrey, R., Kamaya, A. 2021

  Abstract

  To evaluate angle-corrected peak systolic cystic artery velocity (CAv) as a predictor of acute cholecystitis among patients presenting to the emergency department (ED) with right upper quadrant (RUQ) pain.In this IRB-approved and retrospective study, CAv was evaluated in 73 patients, 43 who underwent definitive treatment with cholecystectomy or percutaneous cholecystostomy and 30 control patients without clinical suspicion for cholecystitis. In addition to CAv, the following were reviewed by 3 radiologists: CBD diameter, cholelithiasis, impacted stone in the neck, sludge, gallbladder wall thickness > 3 mm, gallbladder transverse dimension ≥ 4 cm, longitudinal dimension ≥ 8 cm, tensile gallbladder fundus sign, pericholecystic fluid, pericholecystic echogenic fat, and sonographic Murphy sign.Of the 43 patients who underwent definitive treatment, 25 had acute cholecystitis (34%) and 18 (25%) had chronic cholecystitis. Average CAv measurements were 50 ± 16 cm/s (acute), 28 ± 8 cm/s (chronic), and 22 ± 8 cm/s (control; p < 0.0001). In univariate analysis, among patients who underwent definitive therapy, CAv ≥ 40 cm/s, gallbladder wall thickness, stone impaction, GB long dimension ≥ 8 cm, and elevated WBC were associated with acute cholecystitis (p < 0.05). In multivariate analysis, CAv ≥ 40 cm/s was the only statistically significant variable (p = 0.016). CAv ≥ 40 cm/s alone had a PPV of 94.7% and overall accuracy of 81.4% in diagnosing acute cholecystitis.CAv ≥ 40 cm/s is highly associated with acute cholecystitis in patients presenting to the ED with RUQ pain.

  View details for DOI 10.1007/s00261-021-03020-z

  View details for PubMedID 34216245

• Longitudinal Ultrasound Assessment of Changes in Size and Number of Incidentally-Detected Gallbladder Polyps. AJR. American journal of roentgenology Walsh, A. J., Bingham, D. B., Kamaya, A. 2021

  Abstract

  Background: Recent European multisociety guidelines recommend routine follow-up imaging of gallbladder polyps (including polyps <6 mm in patients without risk factors) and size change of ≥2 mm to prompt cholecystectomy. Objective: To assess longitudinal changes in the number and size of gallbladder polyps on serial ultrasound examinations. Methods: This retrospective study included patients who underwent at least one screening ultrasound examination between January 2010 and December 2020 as part of a hepatocellular carcinoma screening and surveillance program that demonstrated a gallbladder polyp. Number of polyps and size of largest polyp were recorded based primarily on review of examination reports. Longitudinal changes on serial examinations were summarized. Pathologic findings from cholecystectomy were reviewed. Results: Among 9683 patients, 759 (8%) had at least one ultrasound examination showing a polyp. Of these, 434 patients (248 male, 186 female; mean age, 50.6 years) had multiple examinations (range, 2-19 examinations; mean 4.8 examinations per patient; mean interval between first and last examinations of 3.6 ± 3.1 years, maximum 11.0 years). Among these 434 patients, 257 had one polyp, 40 had two polyps, and 137 had more than 2 polyps. Polyp size was ≤6 mm in 368 patients, 7-9 mm in 52 patients, and ≥10 mm in 14 patients. Number of polyps increased in 9%, decreased in 14%, both increased and decreased on serial examinations in 22%, and showed no change in 55%. Polyp size increased in 10%, decreased in 16%, both increased and decreased on serial examinations in 18%, and showed no change in 56%. In 9% of patients, gallbladder polyps were not detected on follow-up imaging; in 6% of patients, gallbladder polyps were not detected on a follow-up examination but then detected on later studies. No gallbladder carcinoma was identified in nineteen patients who underwent cholecystectomy. Conclusion: Gallbladder polyps fluctuate in size, number, and visibility over serial examinations. Using 2 mm threshold for growth, 10% increased in size. No carcinoma was identified. Clinical Impact: Recent European multisociety guidelines that propose surveillance of essentially all polyps and a 2 mm size change as basis for cholecystectomy are likely too conservative for clinical application.

  View details for DOI 10.2214/AJR.21.26614

  View details for PubMedID 34549608

• Prevalence of Malignancy and Histopathologic Association of Bosniak Classification, Version 2019 Class III and IV Cystic Renal Masses. The Journal of urology Tse, J. R., Shen, L., Shen, J., Yoon, L., Kamaya, A. 2020: 101097JU0000000000001438

  Abstract

  PURPOSE: Bosniak Classification, version 2019 (v2019) describes two types of class III and IV masses each: 1) thick, wall/septa ≥4 mm (III-WS), 2) obtuse protrusion ≤3 mm (III-OP), 3) obtuse protrusion ≥4 mm (IV-OP), and 4) acute protrusion of any size (IV-AP). The purposes were to determine the prevalence of malignancy and histopathologic features of class III and IV masses and subclasses.MATERIALS AND METHODS: In this IRB-approved and HIPAA-compliant study, three fellowship-trained abdominal radiologists (R1-3) reviewed cystic renal masses that had tissue pathology and pre-operative renal mass protocol CT or MRI. Classes based on v2019 and prior classification systems were retrospectively re-assigned and associated with malignancy, aggressive histologic features (necrosis or high Fuhrman grade), and radiologic progression following resection.RESULTS: The final sample included 79 masses (59 malignant, 20 benign) from 74 patients. Based on v2019, prevalence of malignancy ranged from 56-61% (mean 60%) for class III and 83-83% (mean 83%) for class IV (p=0.036, 0.013, 0.036 for R1-3). Prevalence of malignancy within subclasses were: III-WS (47-53%); III-OP (71-85%); IV-OP (75-87%); IV-AP (87-95%; p=0.029, 0.001, 0.005). All readers were more likely to classify malignancies with aggressive histologic features as class IV (88-100%) rather than class III (0-12%; p=0.012, <0.001, 0.002), corresponding to a negative predictive value of 96-100%. Following treatment (mean follow-up length 1210 days), one patient developed metastases.CONCLUSIONS: Bosniak Classification, version 2019 can help risk stratification of class III-IV masses by identifying those likely to be malignant and have aggressive histologic features.

  View details for DOI 10.1097/JU.0000000000001438

  View details for PubMedID 33085925

• ACR Appropriateness Criteria Chronic Liver Disease. Journal of the American College of Radiology : JACR Expert Panel on Gastrointestinal Imaging, Bashir, M. R., Horowitz, J. M., Kamel, I. R., Arif-Tiwari, H., Asrani, S. K., Chernyak, V., Goldstein, A., Grajo, J. R., Hindman, N. M., Kamaya, A., McNamara, M. M., Porter, K. K., Solnes, L. B., Srivastava, P. K., Zaheer, A., Carucci, L. R. 2020; 17 (5S): S70–S80

  Abstract

  The liver fibrosis stage is the most important clinical determinate of morbidity and mortality in patients with chronic liver diseases. With newer therapies, liver fibrosis can be stabilized and possibly reversed, thus accurate diagnosis and staging of liver fibrosis are clinically important. Ultrasound, CT, and conventional MRI can be used to establish the diagnosis of advanced fibrosis/cirrhosis but have limited utility for assessing earlier stages of fibrosis. Elastography-based ultrasound and MRI techniques are more useful for assessment of precirrhotic hepatic fibrosis. In patients with advanced fibrosis at risk for hepatocellular carcinoma (HCC), ultrasound is the surveillance modality recommended by international guidelines in nearly all circumstances. However, in patients in whom ultrasound does not assess the liver well, including those with severe steatosis or obesity, multiphase CT or MRI may have a role in surveillance for HCC. Both multiphase CT and MRI can be used for continued surveillance in patients with a history of HCC, and contrast-enhanced ultrasound may have an emerging role in this setting. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

  View details for DOI 10.1016/j.jacr.2020.01.023

  View details for PubMedID 32370979

• Quantitative ultrasound approaches for diagnosis and monitoring hepatic steatosis in nonalcoholic fatty liver disease. Theranostics Pirmoazen, A. M., Khurana, A., El Kaffas, A., Kamaya, A. 2020; 10 (9): 4277-4289

  Abstract

  Nonalcoholic fatty liver disease is a major global health concern with increasing prevalence, associated with obesity and metabolic syndrome. Recently, quantitative ultrasound-based imaging techniques have dramatically improved the ability of ultrasound to detect and quantify hepatic steatosis. These newer ultrasound techniques possess many inherent advantages similar to conventional ultrasound such as universal availability, real-time capability, and relatively low cost along with quantitative rather than a qualitative assessment of liver fat. In addition, quantitative ultrasound-based imaging techniques are less operator dependent than traditional ultrasound. Here we review several different emerging quantitative ultrasound-based approaches used for detection and quantification of hepatic steatosis in patients at risk for nonalcoholic fatty liver disease. We also briefly summarize other clinically available imaging modalities for evaluating hepatic steatosis such as MRI, CT, and serum analysis.

  View details for DOI 10.7150/thno.40249

  View details for PubMedID 32226553

  View details for PubMedCentralID PMC7086372

• Bosniak Classification Version 2019 of Cystic Renal Masses Assessed With MRI. AJR. American journal of roentgenology Tse, J. R., Shen, J. n., Yoon, L. n., Kamaya, A. n. 2020: 1–7

  Abstract

  OBJECTIVE. The purpose of this study was to determine how use of Bosniak classification version 2019 affects categorization and overall accuracy of MRI evaluation of cystic renal masses with tissue pathologic analysis as the reference standard. MATERIALS AND METHODS. MR images of 50 consecutively registered patients with tissue pathologic results from 2005 to 2019 were retrospectively reviewed by two abdominal radiologists. Each radiologist independently assigned a category based on the original and Bosniak classification version 2019 systems. Interreader agreements (kappa statistic) for both were calculated, and consensus reading was performed. Tissue pathologic analysis was used as the reference standard to determine whether a lesion was benign or renal cell carcinoma. RESULTS. Fifty-nine cystic renal masses were characterized as 38 renal cell carcinomas and 21 benign lesions on the basis of the results of tissue pathologic analysis. By consensus, according to the original Bosniak criteria, the renal masses were classified into three category I, five category II, four category IIF, 25 category III, and 22 category IV lesions. By consensus, according to the version 2019 criteria, the renal masses were classified into three category I, two category II, 12 category IIF, 18 category III, and 24 category IV lesions. Overall sensitivity and specificity for identifying renal cell carcinoma were 95% and 81%, respectively, with the original classification system and 100% and 86%, respectively, with version 2019. Weighted interreader agreement was moderate for both the original system (κ = 0.57) and version 2019 (κ = 0.55). CONCLUSION. Use of Bosniak classification version 2019 system improves sensitivity and specificity for malignancy among cystic renal masses characterized with MRI. Most lesions that changed categories were reclassified as Bosniak category IIF.

  View details for DOI 10.2214/AJR.19.22740

  View details for PubMedID 32515608

• Learning steatosis staging with two-dimensional Convolutional Neural Networks: comparison of accuracy of clinical B-mode with a co-registered spectrogram representation of RF Data Sanabria, S. J., Dahl, J., Pirmoazen, A., Kamaya, A., ElKaffas, A., IEEE IEEE. 2020

  View details for Web of Science ID 000635688900031

• Multi-parametric Ultrasound Tissue Characterization (MUTC) as a surrogate to Magnetic Resonance Imaging (MRI) for Non-Alcoholic Fatty Liver Disease (NAFLD) characterization. Sanabria, S. J., Dahl, J., Pirmoazen, A., Kamaya, A., ElKaffas, A., IEEE IEEE. 2020

  View details for Web of Science ID 000635688900497

• ACR Appropriateness Criteria® Liver Lesion-Initial Characterization. Journal of the American College of Radiology : JACR Chernyak, V. n., Horowitz, J. M., Kamel, I. R., Arif-Tiwari, H. n., Bashir, M. R., Cash, B. D., Farrell, J. n., Goldstein, A. n., Grajo, J. R., Gupta, S. n., Hindman, N. M., Kamaya, A. n., McNamara, M. M., Porter, K. K., Solnes, L. B., Srivastava, P. K., Zaheer, A. n., Carucci, L. R. 2020; 17 (11S): S429–S446

  Abstract

  Incidental liver masses are commonly identified on imaging performed for other indications. Since the prevalence of benign focal liver lesions in adults is high, even in patients with primary malignancy, accurate characterization of incidentally detected lesions is of paramount clinical importance. This document reviews utilization of various imaging modalities for characterization of incidentally detected liver lesions, discussed in the context of several clinical scenarios. For each clinical scenario, a summary of current evidence supporting the use of a given diagnostic modality is reported. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

  View details for DOI 10.1016/j.jacr.2020.09.005

  View details for PubMedID 33153555

• Effects of Contrast-Enhanced Ultrasound of Indeterminate Renal Masses on Patient Clinical Management: Retrospective Analysis from Two Institutions: Retrospective Analysis From 2 Institutions. Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine Eisenbrey, J. R., Kamaya, A. n., Gummadi, S. n., Bird, K. n., Burrowes, D. n., Arias, D. n., Lallas, C. D., Trabulsi, E. J., Lyshchik, A. n. 2020

  Abstract

  To investigate the long-term impact of contrast-enhanced ultrasound (CEUS) on the treatment of patients with indeterminate renal masses.In this retrospective study, consecutive charts of all patients receiving renal CEUS at 1 of 2 academic medical centers between January 1, 2014, and December 31, 2018, were reviewed. Patients were included in the study if they had documented chronic renal disease (estimated glomerular filtration rate < 60 mL/min/1.73 m2 ) or prior nephrectomy and received CEUS for a previously untreated renal mass.A total of 215 lesions in 157 patients were used for analysis. Contrast-enhanced ultrasound provided a final treatment recommendation in 71.6% of lesions (154 of 215). Of these 154 lesions, 7.8% (12 of 154) were lost to follow-up despite CEUS suggesting malignancy; 15.6% (24 of 154) went directly for surgical intervention, with malignancy confirmed by pathologic results in 87.5% (21 of 24) of these cases; and the remaining 76.6% (118 of 154) were deemed benign and required no additional follow-up. Of the 118 lesions diagnosed by CEUS as benign and requiring no follow-up, none showed evidence of later renal cell carcinoma development and, only 5.1% (6 of 118) of the total population was referred for further cross-sectional imaging of the mass in question. In 28.4% of all lesions (61 of 215), CEUS resulted in a recommendation for surveillance imaging at a 6- to 12-month interval, and less than 10% (6 of 61) of these underwent additional cross-sectional imaging within the recommended 6 months after CEUS.These findings highlight the impact of CEUS on clinical treatment of indeterminate renal masses, including reducing the use of the potentially nephrotoxic contrast agents and providing a direct pathway to transplant.

  View details for DOI 10.1002/jum.15383

  View details for PubMedID 32657452

• Online Liver Imaging Course; Pivoting to Transform Radiology Education During the SARS-CoV-2 Pandemic. Academic radiology Elsayes, K. M., Marks, R. M., Kamel, S. n., Towbin, A. J., Kielar, A. Z., Patel, P. n., Chernyak, V. n., Fowler, K. J., Nassar, S. n., Soliman, M. A., Kamaya, A. n., Mendiratta-Lala, M. n., Borhani, A. A., Fetzer, D. T., Fung, A. W., Do, R. K., Bashir, M. R., Lee, J. n., Consul, N. n., Olmsted, R. n., Kambadone, A. n., Taouli, B. n., Furlan, A. n., Sirlin, C. B., Hsieh, P. n. 2020

  Abstract

  The SARS-CoV-2 pandemic has drastically disrupted radiology in-person education. The purpose of this study was to assess the implementation of a virtual teaching method using available technology and its role in the continuity of education of practicing radiologists and trainees during the pandemic.The authors created the Online Liver Imaging Course (OLIC) that comprised 28 online comprehensive lectures delivered in real-time and on-demand over six weeks. Radiologists and radiology trainees were asked to register to attend the live sessions. At the end of the course, we conducted a 46-question survey among registrants addressing their training level, perception of virtual conferencing, and evaluation of the course content.One thousand four hundred and thirty four radiologists and trainees completed interest sign up forms before the start of the course with the first webinar having the highest number of live attendees (343 people). On average, there were 89 live participants per session and 750 YouTube views per recording (as of July 9, 2020). After the end of the course, 487 attendees from 37 countries responded to the postcourse survey for an overall response rate of (33%). Approximately (63%) of participants were practicing radiologists while (37%) were either fellows or residents and rarely medical students. The overwhelming majority (97%) found the OLIC webinar series to be beneficial. Essentially all attendees felt that the webinar sessions met (43%) or exceeded (57%) their expectations. When asked about their perception of virtual conferences after attending OLIC lectures, almost all attendees (99%) enjoyed the virtual conference with a majority (61%) of the respondents who enjoyed the virtual format more than in-person conferences, while (38%) enjoyed the webinar format but preferred in-person conferences. When asked about the willingness to attend virtual webinars in the future, (84%) said that they would attend future virtual conferences even if in-person conferences resume while (15%) were unsure.The success of the OLIC, attributed to many factors, indicates that videoconferencing technology provides an inexpensive alternative to in-person radiology conferences. The positive responses to our postcourse survey suggest that virtual education will remain to stay. Educational institutions and scientific societies should foster such models.

  View details for DOI 10.1016/j.acra.2020.10.001

  View details for PubMedID 33109449

• ACR Appropriateness Criteria® Pancreatic Cyst. Journal of the American College of Radiology : JACR Fábrega-Foster, K. n., Kamel, I. R., Horowitz, J. M., Arif-Tiwari, H. n., Bashir, M. R., Chernyak, V. n., Goldstein, A. n., Grajo, J. R., Hindman, N. M., Kamaya, A. n., McNamara, M. M., Porter, K. K., Scheiman, J. M., Solnes, L. B., Srivastava, P. K., Zaheer, A. n., Carucci, L. R. 2020; 17 (5S): S198–S206

  Abstract

  Incidental pancreatic cysts are increasingly detected on imaging studies performed for unrelated indications and may be incompletely characterized on these studies. Adequate morphological characterization is critical due to the small risk of malignant degeneration associated with neoplastic pancreatic cysts, as well as the risk of associated pancreatic adenocarcinoma. For all pancreatic cysts, both size and morphology determine management. Specifically, imaging detection of features, such as pancreatic ductal communication and presence or absence of worrisome features or high-risk stigmata, have important management implications. The recommendations in this publication determine the appropriate initial imaging study to further evaluate a pancreatic cyst that was incidentally detected on a nondedicated imaging study. The recommendations are designed to maximize the yield of diagnostic information in order to better risk-stratify pancreatic cysts and assist in guiding future management. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

  View details for DOI 10.1016/j.jacr.2020.01.021

  View details for PubMedID 32370963

• Bosniak Classification of Cystic Renal Masses Version 2019: Comparison of Categorization using CT and MRI. AJR. American journal of roentgenology Tse, J. R., Shen, J. n., Shen, L. n., Yoon, L. n., Kamaya, A. n. 2020

  Abstract

  Please see the Author Video associated with this article. Background: Bosniak Classification, version 2019 recently proposed refinements for cystic renal mass characterization and now formally incorporates MRI, which may improve concordance with CT. Purpose: To compare concordance of CT and MRI in evaluation of cystic renal masses using Bosniak Classification, version 2019. Materials and Methods: In this IRB-approved and HIPAA compliant study, three abdominal radiologists (R1-R3) retrospectively reviewed 68 consecutive cystic renal masses from 45 patients assessed with both CT and MR renal mass protocols within a year between 2005-2019. CT and MRI were reviewed independently and in separate sessions, using both the original and version 2019 Bosniak Classification systems. Results: Using Bosniak Classification, version 2019, cystic renal masses were classified into 12 category I, 19 category II, 13 category IIF, 4 category III, and 20 category IV by CT and 8 category I, 15 category II, 23 category IIF, 9 category III, and 13 category IV by MRI. Among individual features, MRI depicted more septa (p<0.001, p=0.046, p=0.005 for R1-R3; McNemar's test) for all radiologists, though both CT and MRI showed a similar number of protrusions (p=0.823, 1.0, 0.302) and maximal septa/wall thickness (p=1.0, 1.0, 0.145). Of discordant cases with version 2019, MRI led to the higher category in 12 masses. Reason for upgrade was most commonly due to protrusions identified only on MRI (n=4), increased number of septa (n=3), and a new category of heterogeneously T1-hyperintense (n=3). Neither modality was more likely to lead to a category change for both version 2019 (p=0.502; McNemar's test) and the original Bosniak classification system (p=0.823). Overall inter-rater agreement was substantial for both CT (κ=0.745) and MRI (κ=0.655) using version 2019 and was slightly higher than that of the original system (CT κ=0.707; MRI κ=0.623). Conclusion: CT and MRI were concordant in the majority of cases using Bosniak Classification, version 2019 and category changes by modality were not statistically significant. Inter-rater agreements were substantial for both CT and MRI. Clinical Impact: Bosniak Classification, version 2019 applied to cystic renal masses has substantial inter-rater agreement and does not lead to systematic category upgrades with either CT or MRI.

  View details for DOI 10.2214/AJR.20.23656

  View details for PubMedID 32755181

• Quantitative ultrasound approaches for diagnosis and monitoring hepatic steatosis in nonalcoholic fatty liver disease THERANOSTICS Pirmoazen, A. M., Khurana, A., El Kaffas, A., Kamaya, A. 2020; 10 (9): 4277–89

  View details for DOI 10.7150/thno.40249

  View details for Web of Science ID 000518773300030

• Ultrasound Liver Imaging Reporting and Data System (US LI-RADS): An Overview with Technical and Practical Applications. Academic radiology Choi, H. H., Rodgers, S. K., Fetzer, D. T., Wasnik, A. P., Millet, J. D., Morgan, T. A., Dawkins, A. n., Gabriel, H. n., Kamaya, A. n. 2020

  Abstract

  The Ultrasound Liver Imaging Reporting and Data System (US LI-RADS), introduced in 2017 by the American College of Radiology, standardizes the technique, interpretation, and reporting of screening and surveillance ultrasounds intended to detect hepatocellular carcinoma in high-risk patients. These include patients with cirrhosis of any cause as well as subsets of patients with chronic hepatitis B viral infection. The US LI-RADS scheme is composed of an ultrasound category and a visualization score: ultrasound categories define the exam as negative, subthreshold, or positive and direct next steps in management; visualization scores denote the expected sensitivity of the exam, based on adequacy of liver visualization with ultrasound. Since its introduction, multiple institutions across the United States have implemented US LI-RADS. This review includes a background of hepatocellular carcinoma and US LI-RADS, definition of screening/surveillance population, recommendations and tips for technique, interpretation, and reporting, and preliminary outcomes analysis.

  View details for DOI 10.1016/j.acra.2020.06.004

  View details for PubMedID 32718745

• Mapping the Ultrasound Landscape to Define Point-of-Care Ultrasound and Diagnostic Ultrasound: A White Paper From the Society of Radiologists in Ultrasound and ACR Commission on Ultrasound. Journal of the American College of Radiology : JACR Patel, M. D., Horrow, M. M., Kamaya, A. n., Frates, M. C., Dahiya, N. n., Golding, L. n., Chong, W. K., Gerena, M. n., Ghate, S. n., Glanc, P. n., Goldbach, A. R., Gupta, S. n., Hill, P. A., Johnson, S. I., Kocher, M. R., Rubin, E. n., Sohaey, R. n., Waltz, J. T., Wolfman, D. J., Middleton, W. D. 2020

  Abstract

  Current descriptions of ultrasound evaluations, including use of the term "point-of-care ultrasound" (POCUS), are imprecise because they are predicated on distinctions based on the device used to obtain images, the location where the images were obtained, the provider who obtained the images, or the focus of the examination. This is confusing because it does not account for more meaningful distinctions based on the setting, comprehensiveness, and completeness of the evaluation. In this white paper, the Society of Radiologists in Ultrasound and the ACR Commission on Ultrasound articulate a map of the ultrasound landscape that divides sonographic evaluations into four distinct categories on the basis of setting, comprehensiveness, and completeness. Details of this classification scheme are elaborated, including important clarifications regarding what ensures comprehensiveness and completeness. Practical implications of this framework for future research and reimbursement paradigms are highlighted.

  View details for DOI 10.1016/j.jacr.2020.09.013

  View details for PubMedID 33007309

• HCC Screening: Is Ultrasound Still Needed at Transplant Centers?-Point: Yes, Ultrasound Remains First Line. AJR. American journal of roentgenology Kamaya, A. n., Rodgers, S. K. 2020

  View details for DOI 10.2214/AJR.20.24382

  View details for PubMedID 32812769

• Spatial Characterization of Tumor Perfusion Properties from 3D DCE-US Perfusion Maps are Early Predictors of Cancer Treatment Response. Scientific reports El Kaffas, A. n., Hoogi, A. n., Zhou, J. n., Durot, I. n., Wang, H. n., Rosenberg, J. n., Tseng, A. n., Sagreiya, H. n., Akhbardeh, A. n., Rubin, D. L., Kamaya, A. n., Hristov, D. n., Willmann, J. K. 2020; 10 (1): 6996

  Abstract

  There is a need for noninvasive repeatable biomarkers to detect early cancer treatment response and spare non-responders unnecessary morbidities and costs. Here, we introduce three-dimensional (3D) dynamic contrast enhanced ultrasound (DCE-US) perfusion map characterization as inexpensive, bedside and longitudinal indicator of tumor perfusion for prediction of vascular changes and therapy response. More specifically, we developed computational tools to generate perfusion maps in 3D of tumor blood flow, and identified repeatable quantitative features to use in machine-learning models to capture subtle multi-parametric perfusion properties, including heterogeneity. Models were developed and trained in mice data and tested in a separate mouse cohort, as well as early validation clinical data consisting of patients receiving therapy for liver metastases. Models had excellent (ROC-AUC > 0.9) prediction of response in pre-clinical data, as well as proof-of-concept clinical data. Significant correlations with histological assessments of tumor vasculature were noted (Spearman R > 0.70) in pre-clinical data. Our approach can identify responders based on early perfusion changes, using perfusion properties correlated to gold-standard vascular properties.

  View details for DOI 10.1038/s41598-020-63810-1

  View details for PubMedID 32332790

  View details for PubMedCentralID PMC7181711

• Quantitative Framework for Risk Stratification of Thyroid Nodules With Ultrasound: A Step Toward Automated Triage of Thyroid Cancer. AJR. American journal of roentgenology Galimzianova, A. n., Siebert, S. M., Kamaya, A. n., Rubin, D. L., Desser, T. S. 2020: 1–8

  Abstract

  OBJECTIVE. The purpose of this study was to explore whether a quantitative framework can be used to sonographically differentiate benign and malignant thyroid nodules at a level comparable to that of experts. MATERIALS AND METHODS. A dataset of ultrasound images of 92 biopsy-confirmed nodules was collected retrospectively. The nodules were delineated and annotated by two expert radiologists using the standardized Thyroid Imaging Reporting and Data System lexicon of the American College of Radiology. In the framework studied, quantitative features of echogenicity, texture, edge sharpness, and margin curvature properties of thyroid nodules were analyzed in a regularized logistic regression model to predict malignancy of a nodule. The framework was validated by leave-one-out cross-validation technique, and ROC AUC, sensitivity, and specificity were used to compare with those obtained with six expert annotation-based classifiers. RESULTS. The AUC of the proposed method was 0.828 (95% CI, 0.715-0.942), which was greater than or comparable to that of the expert classifiers, for which the AUC values ranged from 0.299 to 0.829 (p = 0.99). Use of the proposed framework could have avoided biopsy of 20 of 46 benign nodules in a curative strategy (at sensitivity of 1, statistically significantly higher than three expert classifiers) or helped identify 10 of 46 malignancies in a conservative strategy (at specificity of 1, statistically significantly higher than five expert classifiers). CONCLUSION. When the proposed quantitative framework was used, thyroid nodule malignancy was predicted at the level of expert classifiers. Such a framework may ultimately prove useful as the basis for a fully automated system of thyroid nodule triage.

  View details for DOI 10.2214/AJR.19.21350

  View details for PubMedID 31967504

• An update for LI-RADS: Version 2018. Why so soon after version 2017? JOURNAL OF MAGNETIC RESONANCE IMAGING Kielar, A. Z., Chernyak, V., Bashir, M. R., Do, R. K., Fowler, K. J., Santillan, C., Sirlin, C. B., Mitchell, D. G., Cerny, M., Tang, A., Elsayes, K. M., Kamaya, A., Kono, Y., Arora, S. S. 2019; 50 (6): 1990–91

  View details for DOI 10.1002/jmri.26715

  View details for Web of Science ID 000496602700031

• Ultrasound Assessment of Acute Kidney Injury ULTRASOUND QUARTERLY Kelahan, L. C., Desser, T. S., Troxell, M. L., Kamaya, A. 2019; 35 (2): 173–80

  View details for DOI 10.1097/RUQ.0000000000000389

  View details for Web of Science ID 000474131600014

• Role of US LI-RADS in the LI-RADS Algorithm. Radiographics : a review publication of the Radiological Society of North America, Inc Rodgers, S. K., Fetzer, D. T., Gabriel, H., Seow, J. H., Choi, H. H., Maturen, K. E., Wasnik, A. P., Morgan, T. A., Dahiya, N., O'Boyle, M. K., Kono, Y., Sirlin, C. B., Kamaya, A. 2019; 39 (3): 690–708

  Abstract

  The US Liver Imaging Reporting and Data System (LI-RADS) was released in 2017 and is the newest of the four American College of Radiology (ACR) LI-RADS algorithms. US LI-RADS provides standardized terminology, technical recommendations, and a reporting framework for US examinations performed for screening or surveillance in patients at risk for developing hepatocellular carcinoma (HCC). The appropriate patient population for screening and surveillance includes individuals who are at risk for developing HCC but do not have known or suspected cancer. This includes patients with cirrhosis from any cause and subsets of patients with chronic hepatitis B virus infection in the absence of cirrhosis. In an HCC screening or surveillance study, US LI-RADS recommends assigning two scores that apply to the entire study: the US category, which determines follow-up, and a visualization score, which communicates the expected level of sensitivity of the examination but does not affect management. Three US categories are possible: US-1 negative, a study with no evidence of HCC; US-2 subthreshold, a study in which an observation less than 10 mm is depicted that is not definitely benign; and US-3 positive, a study in which an observation greater than or equal to 10 mm or a new thrombus in vein is identified, for which diagnostic contrast material-enhanced imaging is recommended. Three visualization scores are possible: A (no or minimal limitations), B (moderate limitations), and C (severe limitations). ©RSNA, 2019.

  View details for PubMedID 31059393

• Ultrasound Evaluation in Patients at Risk for Hepatocellular Carcinoma RADIOLOGIC CLINICS OF NORTH AMERICA Fetzer, D. T., Rodgers, S. K., Seow, J. H., Dawkins, A. A., Joshi, G., Gabriel, H., Kamaya, A. 2019; 57 (3): 563-+

  View details for DOI 10.1016/j.rcl.2019.01.004

  View details for Web of Science ID 000466246400008

• Early Changes in CT Perfusion Parameters: Primary Renal Carcinoma Versus Metastases After Treatment with Targeted Therapy CANCERS Fan, A. C., Sundaram, V., Kino, A., Schmiedeskamp, H., Metzner, T. J., Kamaya, A. 2019; 11 (5)

  View details for DOI 10.3390/cancers11050608

  View details for Web of Science ID 000472738300021

• Association of advanced hepatic fibrosis and sonographic visualization score: a dual-center study using ACR US LI-RADS ABDOMINAL RADIOLOGY Choi, H. H., Perez, M. G., Millet, J. D., Liang, T., Wasnik, A. P., Maturen, K. E., Kamaya, A. 2019; 44 (4): 1415–22

  View details for DOI 10.1007/s00261-018-1862-z

  View details for Web of Science ID 000462749100022

• ACR Appropriateness Criteria® Jaundice. Journal of the American College of Radiology : JACR Hindman, N. M., Arif-Tiwari, H. n., Kamel, I. R., Al-Refaie, W. B., Bartel, T. B., Cash, B. D., Chernyak, V. n., Goldstein, A. n., Grajo, J. R., Horowitz, J. M., Kamaya, A. n., McNamara, M. M., Porter, K. K., Srivastava, P. K., Zaheer, A. n., Carucci, L. R. 2019; 16 (5S): S126–S140

  Abstract

  Jaundice is the end result of myriad causes, which makes the role of imaging in this setting particularly challenging. In the United States, the most common causes of all types of jaundice fall into four categories including hepatitis, alcoholic liver disease, blockage of the common bile duct by a gallstone or tumor, and toxic reaction to a drug or medicinal herb. Clinically, differentiating between the various potential etiologies of jaundice requires a detailed history, targeted physical examination, and pertinent laboratory studies, the results of which allow the physician to categorize the type of jaundice into mechanical or nonmechanical causes. Imaging modalities used to evaluate the jaundiced patient (all etiologies) include abdominal ultrasound (US), CT, MR cholangiopancreatography, endoscopic retrograde cholangiopancreatography and endoscopic US. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

  View details for PubMedID 31054739

• ACR Appropriateness Criteria® Acute Pancreatitis. Journal of the American College of Radiology : JACR Porter, K. K., Zaheer, A. n., Kamel, I. R., Horowitz, J. M., Arif-Tiwari, H. n., Bartel, T. B., Bashir, M. R., Camacho, M. A., Cash, B. D., Chernyak, V. n., Goldstein, A. n., Grajo, J. R., Gupta, S. n., Hindman, N. M., Kamaya, A. n., McNamara, M. M., Carucci, L. R. 2019; 16 (11S): S316–S330

  Abstract

  Acute pancreatitis (AP) is divided into two types: interstitial edematous and necrotizing. AP severity is classified clinically into mild, moderately severe, and severe, depending on the presence and persistence of organ failure and local or systemic complications. The revised Atlanta classification divides the clinical course of AP into an early (first week) and late phase (after first week) and the clinical phase determines the role of imaging. Imaging has a limited role in the early phase. In the early phase with typical presentations of AP, ultrasound is usually the only appropriate modality and is used for the detection of gallstones. CT and MRI are appropriate in the early phase in equivocal presentations. In the late phase (or at least 48-72 hours after presentation), CT and MRI play a primary role in the imaging of patients with AP for evaluation of etiology, complications, extent of disease, intervention, and follow-up; CT is particularly useful in patients with suspected acute hemorrhage. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

  View details for DOI 10.1016/j.jacr.2019.05.017

  View details for PubMedID 31685100

• Bladder cancer and its mimics: a sonographic pictorial review with CT/MR and histologic correlation. Abdominal radiology (New York) Wentland, A. L., Desser, T. S., Troxell, M. L., Kamaya, A. n. 2019

  Abstract

  Bladder cancer is the most common cancer of the urinary system and often presents with hematuria. Despite its relatively high incidence, bladder cancer is often under-recognized sonographically. Moreover, even when bladder abnormalities are identified, numerous other entities may mimic the appearance of bladder cancer. Given the incidence and prevalence of bladder cancer, it is important to recognize its variable appearance sonographically and distinguish it from its common mimics. We review the sonographic appearance of bladder cancer and its mimics, providing correlative CT/MR imaging as well as pathology. We stress the importance and advantage of ultrasound as a dynamic imaging modality, with the ability to optimize distinguishing bladder cancer from similar-appearing entities.

  View details for DOI 10.1007/s00261-019-02276-w

  View details for PubMedID 31676920

• Does measurement of the hepatic artery velocity improve the sonographic diagnosis of cholangitis? Abdominal radiology (New York) Tse, J. R., Liang, T. n., Jeffrey, R. B., Kamaya, A. n. 2019

  Abstract

  To determine the frequency of elevated peak systolic proper hepatic artery velocity (HAV) in patients with acute cholangitis and to determine the diagnostic performance of this metric relative to existing criteria.Between 9/2016 and 11/2017, 107 patients clinically suspected to have cholangitis were referred for an abdominal ultrasound. Of these, 56 patients had HAV measurements and were included in the final analysis. Clinical and imaging features, including HAV, HAV resistive index (RI), portal vein velocity (PVV), biliary dilation, and presence of an obstructive etiology were extracted. The diagnostic performance of HAV was compared to the existing available clinical criteria (Charcot's triad and 2018 Tokyo Guidelines). Elevated HAV was defined as HAV > 100 cm/s. Presence of cholangitis was determined by the discharge summary following medical workup and admission or observation.32% had cholangitis while 68% did not. Average HAV for patients with cholangitis was 152 ± 54 cm/s versus 91 ± 44 cm/s for those without (p < 0.0001; t test). The HAV was elevated in 83% of patients with cholangitis. When considered in isolation, an elevated HAV had a high negative predictive value (90%), was more accurate (77%; 95% confidence interval 64-87%) than Charcot's triad (73%; 60-83%), and had similar accuracy compared to 2018 Tokyo Guidelines (79%; 66-88%). Substitution of conventional imaging criteria with elevated HAV in the 2018 Tokyo Guidelines yielded the highest overall accuracy of 84% (72-92%).HAV is elevated in the majority of patients with cholangitis. Substitution of an elevated HAV for conventional sonographic criteria is more accurate than existing clinical criteria in identifying patients with cholangitis.

  View details for DOI 10.1007/s00261-019-02284-w

  View details for PubMedID 31673717

• ACR Ultrasound Liver Reporting and Data System: Multicenter Assessment of Clinical Performance at 1 Year. Journal of the American College of Radiology : JACR Millet, J. D., Kamaya, A. n., Choi, H. H., Dahiya, N. n., Murphy, P. M., Naveed, M. Z., O'Boyle, M. n., Parra, L. A., Perez, M. n., Pirmoazen, A. n., Rodgers, S. K., Wasnik, A. P., Maturen, K. E. 2019

  Abstract

  The aim of this study was to evaluate the clinical performance of the ACR's Ultrasound Liver Reporting and Data System (US LI-RADS™) for detecting hepatocellular carcinoma (HCC) in patients at high risk for HCC.In this retrospective, multicenter study, 2,050 patients at high risk for HCC (1,078 men and 972 women; mean age, 57.7 years) at five sites in the United States had undergone screening liver ultrasound from January 2017 to February 2018, and US LI-RADS observation categories and visualization scores were assigned on a clinical basis. Ultrasound reports and patient records were retrospectively reviewed and follow-up imaging studies and/or pathologic reports recorded. Descriptive statistics were generated, and multivariate logistic regression analysis was used to analyze the relationship of clinical and reader-based predictors of limited visualization. Diagnostic performance data were calculated in the subset of patients with confirmatory testing.The most common indications for HCC screening were cirrhosis (n = 1,054 [51.4%]), noncirrhotic hepatitis B virus (n = 555 [27.1%]), and noncirrhotic hepatitis C virus (n = 234 [11.4%]). US LI-RADS observation categories assigned were US-1 (negative) in 90.4% (n = 1,854), US-2 (subthreshold) in 4.6% (n = 95), and US-3 (positive) in 4.9% (n = 101). Visualization scores were A (no or minimal limitations) in 76.8% (n = 1,575), B (moderate limitations) in 18.9% (n = 388), and C (severe limitations) in 4.2% (n = 87). Confirmatory tests including multiphase contrast-enhanced CT or MRI (n = 331) or histopathology (n = 18) were available for 349 patients (17.0%). The sensitivity of US LI-RADS in this subset of patients was 82.4%, specificity was 74.2%, positive predictive value was 35.3%, and negative predictive value was 96.1%.Approximately 90% of US LI-RADS screening examinations were negative, 5% subthreshold, and 5% positive. Visualization scores were diagnostically acceptable in the vast majority (>95%) of examinations. US LI-RADS emphasized sensitivity and negative predictive value, key characteristics of a screening test.

  View details for DOI 10.1016/j.jacr.2019.05.020

  View details for PubMedID 31173745

• Utility of ultrasound in acute pancreatitis. Abdominal radiology (New York) Burrowes, D. P., Choi, H. H., Rodgers, S. K., Fetzer, D. T., Kamaya, A. n. 2019

  Abstract

  Ultrasound plays an essential role in the initial evaluation of patients with suspected or confirmed acute pancreatitis. In addition to evaluation of the pancreatic parenchyma, ultrasound is used for assessment of the gallbladder, biliary tree, peripancreatic tissues, and regional vascular structures. While enlarged and edematous pancreas are classic sonographic features of acute pancreatitis, the pancreas may appear sonographically normal in the setting of acute pancreatitis. Nonetheless, sonographic evaluation in this setting is valuable because assessment for etiologic factors such as gallstones or evidence of biliary obstruction are best performed with ultrasound. Complications of pancreatitis such as peripancreatic fluid collections, venous thrombosis, or arterial pseudoaneurysm can be identified with careful and focused ultrasound examination. Knowledge of various scanning techniques can help to mitigate some of the commonly encountered barriers to sonographic visualization of the pancreas and right upper quadrant structures. Ultrasound can also be used for guidance of percutaneous treatment such as drainage of fluid collections or pseudoaneurysm thrombosis. Difficulty in differentiating edematous from necrotizing pancreatitis can be mitigated with the use of contrast-enhanced ultrasound to assess pancreatic parenchymal enhancement.

  View details for DOI 10.1007/s00261-019-02364-x

  View details for PubMedID 31844915

• LI-RADS: a conceptual and historical review from its beginning to its recent integration into AASLD clinical practice guidance. Journal of hepatocellular carcinoma Elsayes, K. M., Kielar, A. Z., Chernyak, V., Morshid, A., Furlan, A., Masch, W. R., Marks, R. M., Kamaya, A., Do, R. K., Kono, Y., Fowler, K. J., Tang, A., Bashir, M. R., Hecht, E. M., Jambhekar, K., Lyshchik, A., Rodgers, S. K., Heiken, J. P., Kohli, M., Fetzer, D. T., Wilson, S. R., Kassam, Z., Mendiratta-Lala, M., Singal, A. G., Lim, C. S., Cruite, I., Lee, J., Ash, R., Mitchell, D. G., McInnes, M. D., Sirlin, C. B. 2019; 6: 49–69

  Abstract

  The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver observations in individuals at high risk for hepatocellular carcinoma (HCC). LI-RADS is supported and endorsed by the American College of Radiology (ACR). Upon its initial release in 2011, LI-RADS applied only to liver observations identified at CT or MRI. It has since been refined and expanded over multiple updates to now also address ultrasound-based surveillance, contrast-enhanced ultrasound for HCC diagnosis, and CT/MRI for assessing treatment response after locoregional therapy. The LI-RADS 2018 version was integrated into the HCC diagnosis, staging, and management practice guidance of the American Association for the Study of Liver Diseases (AASLD). This article reviews the major LI-RADS updates since its 2011 inception and provides an overview of the currently published LI-RADS algorithms.

  View details for PubMedID 30788336

• White paper of the Society of Abdominal Radiology hepatocellular carcinoma diagnosis disease-focused panel on LI-RADS v2018 for CT and MRI ABDOMINAL RADIOLOGY Elsayes, K. M., Kielar, A. Z., Elmohr, M. M., Chernyak, V., Masch, W. R., Furlan, A., Marks, R. M., Cruite, I., Fowler, K. J., Tang, A., Bashir, M. R., Hecht, E. M., Kamaya, A., Jambhekar, K., Kamath, A., Arora, S., Bijan, B., Ash, R., Kassam, Z., Chaudhry, H., McGahan, J. P., Yacoub, J. H., McInnes, M., Fung, A. W., Shanbhogue, K., Lee, J., Deshmukh, S., Horvat, N., Mitchell, D. G., Do, R. G., Surabhi, V. R., Szklaruk, J., Sirlin, C. B. 2018; 43 (10): 2625–42

  Abstract

  The Liver Imaging and Reporting Data System (LI-RADS) is a comprehensive system for standardizing the terminology, technique, interpretation, reporting, and data collection of liver imaging with the overarching goal of improving communication, clinical care, education, and research relating to patients at risk for or diagnosed with hepatocellular carcinoma (HCC). In 2018, the American Association for the Study of Liver Diseases (AASLD) integrated LI-RADS into its clinical practice guidance for the imaging-based diagnosis of HCC. The harmonization between the AASLD and LI-RADS diagnostic imaging criteria required minor modifications to the recently released LI-RADS v2017 guidelines, necessitating a LI-RADS v2018 update. This article provides an overview of the key changes included in LI-RADS v2018 as well as a look at the LI-RADS v2018 diagnostic algorithm and criteria, technical recommendations, and management suggestions. Substantive changes in LI-RADS v2018 are the removal of the requirement for visibility on antecedent surveillance ultrasound for LI-RADS 5 (LR-5) categorization of 10-19 mm observations with nonrim arterial phase hyper-enhancement and nonperipheral "washout", and adoption of the Organ Procurement and Transplantation Network definition of threshold growth (≥ 50% size increase of a mass in ≤ 6 months). Nomenclatural changes in LI-RADS v2018 are the removal of -us and -g as LR-5 qualifiers.

  View details for PubMedID 30155697

• Liver Imaging Reporting and Data System (LI-RADS) Version 2018: Imaging of Hepatocellular Carcinoma in At-Risk Patients. Radiology Chernyak, V., Fowler, K. J., Kamaya, A., Kielar, A. Z., Elsayes, K. M., Bashir, M. R., Kono, Y., Do, R. K., Mitchell, D. G., Singal, A. G., Tang, A., Sirlin, C. B. 2018: 181494

  Abstract

  The Liver Imaging Reporting and Data System (LI-RADS) is composed of four individual algorithms intended to standardize the lexicon, as well as reporting and care, in patients with or at risk for hepatocellular carcinoma in the context of surveillance with US; diagnosis with CT, MRI, or contrast material-enhanced US; and assessment of treatment response with CT or MRI. This report provides a broad overview of LI-RADS, including its historic development, relationship to other imaging guidelines, composition, aims, and future directions. In addition, readers will understand the motivation for and key components of the 2018 update.

  View details for PubMedID 30251931

• Performance of Hepatic Artery Velocity in Evaluation of Causes of Markedly Elevated Liver Tests. Ultrasound in medicine & biology Tse, J. R., Jeffrey, R. B., Kamaya, A. 2018

  Abstract

  The purpose of this study was to assess the utility of peak systolic proper hepatic artery velocity (HAV) in differentiating causes of severely elevated liver function tests. HAV, hepatic artery resistive index and portal vein velocity of 41 patients with severely elevated liver function tests were evaluated. In 19 patients (46%), the causes were structural (e.g., cholecystitis, cholangitis), whereas in 22 patients (54%) the causes were non-structural (e.g., rhabdomyolysis, drug-induced liver injury). The average HAV for structural causes was 138 ± 68 cm/s, and for non-structural causes, 65 ± 29 cm/s (p < 0.0001). An HAV >100 cm/s was correlated with structural causes (p = 0.0001). With respect to diagnostic performance, this threshold was 79% sensitive and 86% specific, with a high positive likelihood ratio (5.8) and low negative likelihood ratio (0.24). The resistive index and portal vein velocity were not statistically different. In patients with severely elevated liver function tests, an HAV >100 cm/s can help distinguish structural from non-structural causes, which may guide management while awaiting definitive laboratory tests.

  View details for PubMedID 30143340

• Diagnostic Performance of Margin Features in Thyroid Nodules in Prediction of Malignancy. AJR. American journal of roentgenology Siebert, S. M., Gomez, A. J., Liang, T. n., Tahvildari, A. M., Desser, T. S., Jeffrey, R. B., Kamaya, A. n. 2018: 1–6

  Abstract

  The purpose of this study was to evaluate thyroid nodule margins for specific morphologic features and determine the diagnostic performance of these features in differentiating papillary carcinoma from benign thyroid nodules.Nodules measuring 1-3 cm in largest diameter that had been evaluated with high-resolution ultrasound (12-18 MHz) and ultrasound-guided biopsy with definitive pathologic diagnosis were analyzed. Three blinded board-certified readers evaluated high-resolution images of each nodule for jagged edges, lobulated borders, and curved borders along their margins. Reader interpretations were correlated with the pathologic diagnosis to determine the diagnostic performance of each feature. A board-certified pathologist analyzed 10 randomly selected nodules with jagged edges by slide review to evaluate for structural correlation with the imaging finding.The diagnostic performance of jagged edges in papillary carcinoma of the thyroid was 67.4% sensitive and 78.3% specific (odds ratio, 7.44; p < 0.001) for malignancy. Jagged edges correlated with infiltrative variant expansion at slide review. Lobulated borders had sensitivity of 76.1% and specificity of 60.9% for papillary carcinoma (odds ratio, 4.95; p = 0.001) for malignancy. Curved borders were not a significant predictor of papillary carcinoma.Jagged edges and lobulated borders of thyroid nodule margins are statistically significant predictors of papillary carcinoma of the thyroid. Jagged edges correlate with infiltrative-type expansion and may be useful predictors of more aggressive papillary carcinomas.

  View details for PubMedID 29446670

• Diagnostic Ultrasound for Sonographers Kamaya, A., Wong-You-Cheong, J., Woodward, P., Kennedy, A., Sohaey, R., et al Elsevier. 2018
• Central echogenic areas in thyroid nodules: Diagnostic performance in prediction of papillary cancer. European journal of radiology Siebert, S. M., Jeffrey, R. B., Gomez, A. J., Kamaya, A. n. 2018; 101: 45–49

  Abstract

  To determine the diagnostic performance of the "central echogenic area" sonographic finding in differentiating papillary carcinomas from benign nodules and to how this finding may be used to improve fine needle aspiration(FNA) technique/utilization.We retrospectively analyzed ultrasound guided FNAs of thyroid nodules between 1 and 3 cm for central echogenic areas. 92 patients (evenly distributed benign vs papillary carcinoma) were evaluated by a blinded reader for areas of non-shadowing homogenously echogenic centers within the nodules and correlated with FNA proven pathologic diagnosis. A selection of nodules with the central echogenic area finding were selected for further slide review to establish a pathologic basis for the finding.Diagnostic performance of the "central echogenic area" feature in papillary thyroid cancers was 52.2% sensitive and 91.3% specific for papillary thyroid carcinoma with a PPV of 85.7% and NPV of 65.6%. There was a significant correlation with a p < 0.01 between the central echogenic area finding and papillary carcinoma. On pathologic slide review, nodules with central echogenic areas consistently demonstrated a central scar with conglomerate fibrosis and very few viable cells.Despite its relatively low sensitivity, the central echogenic area finding is highly specific for papillary carcinoma of the thyroid and can be a useful sonographic finding in decisions regarding FNA. Additionally, due to the paucity of cells and high density of conglomerate fibrosis, central echogenic areas should be avoided during FNA to decrease the chance of an inadequate sample collection.

  View details for DOI 10.1016/j.ejrad.2018.01.029

  View details for PubMedID 29571800

• LI-RADS 2017: An update. Journal of magnetic resonance imaging : JMRI Kielar, A. Z., Chernyak, V. n., Bashir, M. R., Do, R. K., Fowler, K. J., Mitchell, D. G., Cerny, M. n., Elsayes, K. M., Santillan, C. n., Kamaya, A. n., Kono, Y. n., Sirlin, C. B., Tang, A. n. 2018

  Abstract

  The computed tomography / magnetic resonance imaging (CT/MRI) Liver Imaging Reporting & Data System (LI-RADS) is a standardized system for diagnostic imaging terminology, technique, interpretation, and reporting in patients with or at risk for developing hepatocellular carcinoma (HCC). Using diagnostic algorithms and tables, the system assigns to liver observations category codes reflecting the relative probability of HCC or other malignancies. This review article provides an overview of the 2017 version of CT/MRI LI-RADS with a focus on MRI. The main LI-RADS categories and their application will be described. Changes and updates introduced in this version of LI-RADS will be highlighted, including modifications to the diagnostic algorithm and to the optional application of ancillary features. Comparisons to other major diagnostic systems for HCC will be made, emphasizing key similarities, differences, strengths, and limitations. In addition, this review presents the new Treatment Response algorithm, while introducing the concepts of MRI nonviability and viability. Finally, planned future directions for LI-RADS will be outlined.5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018.

  View details for PubMedID 29626376

• Screening and Surveillance of Hepatocellular Carcinoma: An Introduction to Ultrasound Liver Imaging Reporting and Data System. Radiologic clinics of North America Fetzer, D. T., Rodgers, S. K., Harris, A. C., Kono, Y., Wasnik, A. P., Kamaya, A., Sirlin, C. 2017; 55 (6): 1197-1209

  Abstract

  Given the high prevalence, increasing incidence, and significant morbidity and mortality related to hepatocellular carcinoma (HCC), a robust and cost-effective screening and surveillance program is needed. Most societies recommend ultrasound for HCC screening, despite lack of standardization in imaging acquisition, reporting content and language, and follow-up recommendations. The American College of Radiology Ultrasound Liver Imaging Reporting and Data System (US LI-RADS) fills this unmet need by providing standardization in the use of US in at-risk patients. It is anticipated that US LI-RADS will improve the performance of ultrasound for HCC screening and surveillance and unify management recommendations.

  View details for DOI 10.1016/j.rcl.2017.06.012

  View details for PubMedID 28991560

• Chapter 5 Ultrasound Characteristics of Benign vs Malignant Cervical Lymph Nodes. Seminars in ultrasound, CT, and MR Prativadi, R., Dahiya, N., Kamaya, A., Bhatt, S. 2017; 38 (5): 506-515

  Abstract

  With approximately 800 lymph nodes in the body, and more than one-third found within the head and neck, lymph nodes are a common site for neck pathology. Differentiation between benign and malignant lymph nodes is critical in accurate prognosis; similarly, treatment hinges on accurate identification of the etiology of the pathologic process. Key gray-scale and color Doppler ultrasound criteria can help accurately distinguish between benign and malignant lymph nodes.

  View details for DOI 10.1053/j.sult.2017.05.005

  View details for PubMedID 29031367

• Benign Gynecologic Conditions of the Uterus. Magnetic resonance imaging clinics of North America Kassam, Z., Petkovska, I., Wang, C. L., Trinh, A. M., Kamaya, A. 2017; 25 (3): 577-600

  Abstract

  In this article, the authors review the anatomy, pathophysiology, MR imaging features, and diagnostic criteria for benign uterine conditions, including adenomyosis, uterine leiomyomas, retained products of conception, and uterine arteriovenous malformations. Pearls, pitfalls, and variants are discussed for each entity as well as important imaging features that can affect management decisions.

  View details for DOI 10.1016/j.mric.2017.03.005

  View details for PubMedID 28668161

• MR Imaging-Pathologic Correlation in Ovarian Cancer. Magnetic resonance imaging clinics of North America Stein, E. B., Wasnik, A. P., Sciallis, A. P., Kamaya, A., Maturen, K. E. 2017; 25 (3): 545-562

  Abstract

  There are many ovarian cancer subtypes, giving rise to a range of appearances at gross pathology and magnetic resonance (MR) imaging. Certain fundamental concepts at MR, arising from underlying tissue characteristics, can provide guidance to radiologists in suggesting a diagnosis. The ability of multiparametric MR to risk stratify ovarian masses can contribute substantially to clinical decision making and patient management.

  View details for DOI 10.1016/j.mric.2017.03.004

  View details for PubMedID 28668159

• Reduced dose CT with model-based iterative reconstruction compared to standard dose CT of the chest, abdomen, and pelvis in oncology patients: intra-individual comparison study on image quality and lesion conspicuity. Abdominal radiology Morimoto, L. N., Kamaya, A., Boulay-Coletta, I., Fleischmann, D., Molvin, L., Tian, L., Fisher, G., Wang, J., Willmann, J. K. 2017

  Abstract

  To compare image quality and lesion conspicuity of reduced dose (RD) CT with model-based iterative reconstruction (MBIR) compared to standard dose (SD) CT in patients undergoing oncological follow-up imaging.Forty-four cancer patients who had a staging SD CT within 12 months were prospectively included to undergo a weight-based RD CT with MBIR. Radiation dose was recorded and tissue attenuation and image noise of four tissue types were measured. Reproducibility of target lesion size measurements of up to 5 target lesions per patient were analyzed. Subjective image quality was evaluated for three readers independently utilizing 4- or 5-point Likert scales.Median radiation dose reduction was 46% using RD CT (P < 0.01). Median image noise across all measured tissue types was lower (P < 0.01) in RD CT. Subjective image quality for RD CT was higher (P < 0.01) in regard to image noise and overall image quality; however, there was no statistically significant difference regarding image sharpness (P = 0.59). There were subjectively more artifacts on RD CT (P < 0.01). Lesion conspicuity was subjectively better in RD CT (P < 0.01). Repeated target lesion size measurements were highly reproducible both on SD CT (ICC = 0.987) and RD CT (ICC = 0.97).RD CT imaging with MBIR provides diagnostic imaging quality and comparable lesion conspicuity on follow-up exams while allowing dose reduction by a median of 46% compared to SD CT imaging.

  View details for DOI 10.1007/s00261-017-1140-5

  View details for PubMedID 28417170

• Perfusion CT measurements predict tumor response in rectal carcinoma ABDOMINAL RADIOLOGY Kino, A., Shaffer, J., Maturen, K. E., Schmiedeskamp, H., Koong, A. C., Chang, D. T., Fleischmann, D., Kamaya, A. 2017; 42 (4): 1132-1140

  View details for DOI 10.1007/s00261-016-0983-5

  View details for Web of Science ID 000399166800010

• Doppler Ultrasound in Liver Cirrhosis: Correlation of Hepatic Artery and Portal Vein Measurements With Model for End-Stage Liver Disease Score JOURNAL OF ULTRASOUND IN MEDICINE Park, H. S., Desser, T. S., Jeffrey, R. B., Kamaya, A. 2017; 36 (4): 725-730

  Abstract

  To determine whether hepatic arterial and portal venous Doppler ultrasound measurements of the liver in cirrhotic patients correlate with patients' Model for End-Stage Liver Disease (MELD) scores, splenomegaly, or ascites.Sonographic images and reports were reviewed of 264 patients with hepatic cirrhosis who underwent abdominal ultrasound with Doppler in this internal review board-approved retrospective study. MELD scores were recorded at the time of ultrasound. On gray-scale ultrasound, spleen length was measured and the presence of ascites was noted. Hepatic arterial velocity (HAv) with angle correction, hepatic arterial resistive index, and portal vein velocity with angle correction were measured on Doppler ultrasound. Correlation of hepatic arterial and portal venous Doppler values with MELD score, presence of splenomegaly, and presence of ascites was tested using linear or binary logistic regression analysis. Diagnostic performance of Doppler parameters for high-risk MELD was assessed.The HAv statistically significantly correlated with the MELD score (P = .0001), spleen size (P =.027), and presence of ascites (P =.0001), whereas the hepatic arterial resistive index and portal vein velocity did not correlate with these factors. For MELD scores greater than 19, an HAv greater than 120 cm/s showed accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 74, 42, 90, 67, and 76%, respectively. With an HAv greater than 160 cm/s, the odds ratio for MELD scores greater than 19 was 42.1.We found a statistically significant correlation with elevated HAv and increasing MELD scores, splenomegaly, and presence of ascites in patients with cirrhotic liver disease; this may be a useful imaging biomarker in the evaluation of patients with cirrhosis.

  View details for DOI 10.7863/ultra.16.03107

  View details for Web of Science ID 000397505800006

• Imaging Anatomy: Ultrasound Woodward, P. J., Griffith, J. F., Ahuja, A. T., Kamaya, A., Wong-You-Cheong, J. Elsevier. 2017
• Toward Automated Pre-Biopsy Thyroid Cancer Risk Estimation in Ultrasound. AMIA ... Annual Symposium proceedings. AMIA Symposium Galimzianova, A. n., Siebert, S. M., Kamaya, A. n., Desser, T. S., Rubin, D. L. 2017; 2017: 734–41

  Abstract

  We propose a computational framework for automated cancer risk estimation of thyroid nodules visualized in ultrasound (US) images. Our framework estimates the probability of nodule malignancy using random forests on a rich set of computational features. An expert radiologist annotated thyroid nodules in 93 biopsy-confirmed patients using semantic image descriptors derived from standardized lexicon. On our dataset, the AUC of the proposed method was 0.70, which was comparable to five baseline expert annotation-based classifiers with AUC values from 0.72 to 0.81. Moreover, the use of the framework for decision making on nodule biopsy could have spared five out of 46 benign nodule biopsies at no cost to the health of patients with malignancies. Our results confirm the feasibility of computer-aided tools for noninvasive malignancy risk estimation in patients with thyroid nodules that could help to decrease the number of unnecessary biopsies and surgeries.

  View details for PubMedID 29854139

• Noninvasive radiomics signature based on quantitative analysis of computed tomography images as a surrogate for microvascular invasion in hepatocellular carcinoma: a pilot study. Journal of medical imaging (Bellingham, Wash.) Bakr, S. n., Echegaray, S. n., Shah, R. n., Kamaya, A. n., Louie, J. n., Napel, S. n., Kothary, N. n., Gevaert, O. n. 2017; 4 (4): 041303

  Abstract

  We explore noninvasive biomarkers of microvascular invasion (mVI) in patients with hepatocellular carcinoma (HCC) using quantitative and semantic image features extracted from contrast-enhanced, triphasic computed tomography (CT). Under institutional review board approval, we selected 28 treatment-naive HCC patients who underwent surgical resection. Four radiologists independently selected and delineated tumor margins on three axial CT images and extracted computational features capturing tumor shape, image intensities, and texture. We also computed two types of "delta features," defined as the absolute difference and the ratio computed from all pairs of imaging phases for each feature. 717 arterial, portal-venous, delayed single-phase, and delta-phase features were robust against interreader variability ([Formula: see text]). An enhanced cross-validation analysis showed that combining robust single-phase and delta features in the arterial and venous phases identified mVI (AUC [Formula: see text]). Compared to a previously reported semantic feature signature (AUC 0.47 to 0.58), these features in our cohort showed only slight to moderate agreement (Cohen's kappa range: 0.03 to 0.59). Though preliminary, quantitative analysis of image features in arterial and venous phases may be potential surrogate biomarkers for mVI in HCC. Further study in a larger cohort is warranted.

  View details for PubMedID 28840174

• The utility of hepatic artery velocity in diagnosing patients with acute cholecystitis. Abdominal radiology (New York) Loehfelm, T. W., Tse, J. R., Jeffrey, R. B., Kamaya, A. n. 2017

  Abstract

  To test the diagnostic performance of elevated peak systolic hepatic arterial velocity (HAv) in the diagnosis of acute cholecystitis.229 patients with an ultrasound (US) performed for right upper quadrant (RUQ) pain were retrospectively reviewed. 35 had cholecystectomy within 10 days of ultrasound and were included as test subjects. 47 had normal US and serology and were included as controls. Each test patient US was reviewed for the presence of gallstones, gallbladder distention, sludge, echogenic pericholecystic fat, pericholecystic fluid, gallbladder wall thickening, gallbladder wall hyperemia, and reported sonographic Murphy sign. Demographic, clinical, and hepatic artery parameters at time of original imaging were recorded. Acute cholecystitis at pathology was the primary outcome variable.21 patients had acute cholecystitis and 14 had chronic cholecystitis by pathology. For patients who went to cholecystectomy, HAv ≥100 cm/s to diagnose acute cholecystitis was more accurate (69%) than the original radiology report (63%), the presence of gallstones (51%), and sonographic Murphy sign (50%). Statistically significant predictors of acute cholecystitis included HAv ≥100 cm/s (p = 0.008), older age (p = 0.012), and elevated WBC (p = 0.002), while gallstones (p = 0.077), hepatic artery resistive index (HARI) (p = 0.199), gallbladder distension (p = 0.252), sludge (p = 0.147), echogenic fat (p = 0.184), pericholecystic fluid (p = 0.357), wall thickening (p = 0.434), hyperemia (p = 0.999), and sonographic Murphy sign (p = 0.765) were not significantly correlated with acute cholecystitis compared to chronic cholecystitis.HAv ≥100 cm/s is a useful objective parameter that may improve the performance of US in the diagnosis of acute cholecystitis.

  View details for PubMedID 28840272

• US LI-RADS: ultrasound liver imaging reporting and data system for screening and surveillance of hepatocellular carcinoma. Abdominal radiology (New York) Morgan, T. A., Maturen, K. E., Dahiya, N. n., Sun, M. R., Kamaya, A. n. 2017

  Abstract

  Ultrasound is the most widely used imaging tool for hepatocellular carcinoma (HCC) screening and surveillance. Until now, this method has lacked standardized guidelines for interpretation, reporting, and management recommendations [1-5]. To address this need, the American College of Radiology (ACR) has developed the Ultrasound Liver Imaging Reporting and Data System (US LI-RADS) algorithm. The proposed algorithm has two components: detection scores and visualization scores. The detection score guides management and has three categories: US-1 Negative, US-2 Subthreshold, and US-3 Positive. The visualization score informs the expected sensitivity of the ultrasound examination and also has three categories: Visualization A: No or minimal limitations; Visualization B: Moderate limitations; and Visualization C: Severe limitations. Standardization in ultrasound utilization, reporting, and management in high-risk individuals has the capacity to improve communication with patients and referring physicians, unify screening and surveillance algorithms, impact outcomes, and supply quantitative data for future research.

  View details for PubMedID 28936543

• Epidemiology of hepatocellular carcinoma: target population for surveillance and diagnosis. Abdominal radiology (New York) Tang, A. n., Hallouch, O. n., Chernyak, V. n., Kamaya, A. n., Sirlin, C. B. 2017

  Abstract

  Hepatocellular carcinoma (HCC) is the sixth most common cancer and the second leading cause of cancer mortality worldwide. Incidence rates of liver cancer vary widely between geographic regions and are highest in Eastern Asia and sub-Saharan Africa. In the United States, the incidence of HCC has increased since the 1980s. HCC detection at an early stage through surveillance and curative therapy has considerably improved the 5-year survival. Therefore, medical societies advocate systematic screening and surveillance of target populations at particularly high risk for developing HCC to facilitate early-stage detection. Risk factors for HCC include cirrhosis, chronic infection with hepatitis B virus (HBV), hepatitis C virus (HCV), excess alcohol consumption, non-alcoholic fatty liver disease, family history of HCC, obesity, type 2 diabetes mellitus, and smoking. Medical societies utilize risk estimates to define target patient populations in which imaging surveillance is recommended (risk above threshold) or in which the benefits of surveillance are uncertain (risk unknown or below threshold). All medical societies currently recommend screening and surveillance in patients with cirrhosis and subsets of patients with chronic HBV; some societies also include patients with stage 3 fibrosis due to HCV as well as additional groups. Thus, target population definitions vary between regions, reflecting cultural, demographic, economic, healthcare priority, and biological differences. The Liver Imaging Reporting and Data System (LI-RADS) defines different patient populations for surveillance and for diagnosis and staging. We also discuss general trends pertaining to geographic region, age, gender, ethnicity, impact of surveillance on survival, mortality, and future trends.

  View details for PubMedID 28647765

• Clinical and imaging predictors of management in retained products of conception ABDOMINAL RADIOLOGY Kamaya, A., Krishnarao, P. M., Nayak, N., Jeffrey, R. B., Maturen, K. E. 2016; 41 (12): 2429-2434

  Abstract

  To determine if clinical and ultrasound (US) imaging features help predict management in clinically suspected retained products of conception (RPOC).334 patients sonographically evaluated for RPOC were included in this IRB-approved retrospective study. Of the 334 patients, 176 had sonographic diagnosis of RPOC and comprised the final study group. Patients were managed expectantly, medically, or surgically in accordance with clinical judgment of treating physicians. Pelvic sonograms were retrospectively reviewed for endometrial stripe thickness and vascularity was graded on a 0-3 scale based on appearance relative to myometrium (Grade 0: no vascularity, Grade 1: minimal vascularity, Grade 2: moderate vascularity, Grade 3: marked vascularity). Clinical and imaging predictors of management were evaluated in univariate and multivariate analysis.Mean patient age was 29.6 years and mean gestational age was 17.4 weeks. Most (74.4%) women presented with vaginal bleeding. 83 patients (47.2%) were treated conservatively with expectant management, 42 (23.8%) were treated medically, and 51 (29.0%) required surgical intervention. Mean endometrial stripe thickness was 21.3 mm. 47 women (26.7%) had vascularity score of 0; 50 (28.4%) had score 1; 52 (29.6%) had score 2; and 27 (15.3%) had score 3. In univariate analysis, serum hemoglobin (Hb) (p < 0.0001), endometrial stripe thickness on US (p < 0.005), presenting symptoms (p = 0.03), and US vascularity score (p < 0.005) were statistically significant predictors of final management. In multivariate logistic regression, serum Hb (OR 0.69, 95% CI 0.55-0.86, p < 0.0009), endometrial stripe thickness (OR 1.08, 95% CI 1.04-1.12, p < 0.0001), and US vascularity score (OR 1.77, 95% CI 1.16-2.70, p < 0.01) were statistically significant predictors of need for surgery.Serum Hb, endometrial stripe thickness, and US vascularity score were significant predictors of clinical management, particularly the need for surgical intervention, in women with clinically suspected RPOC.

  View details for DOI 10.1007/s00261-016-0954-x

  View details for Web of Science ID 000390050600015

  View details for PubMedID 27853850

• Robotic intrafractional US guidance for liver SABR: System design, beam avoidance, and clinical imaging. Medical physics Schlosser, J., Gong, R. H., Bruder, R., Schweikard, A., Jang, S., Henrie, J., Kamaya, A., Koong, A., Chang, D. T., Hristov, D. 2016; 43 (11): 5951-?

  Abstract

  To present a system for robotic 4D ultrasound (US) imaging concurrent with radiotherapy beam delivery and estimate the proportion of liver stereotactic ablative body radiotherapy (SABR) cases in which robotic US image guidance can be deployed without interfering with clinically used VMAT beam configurations.The image guidance hardware comprises a 4D US machine, an optical tracking system for measuring US probe pose, and a custom-designed robot for acquiring hands-free US volumes. In software, a simulation environment incorporating the LINAC, couch, planning CT, and robotic US guidance hardware was developed. Placement of the robotic US hardware was guided by a target visibility map rendered on the CT surface by using the planning CT to simulate US propagation. The visibility map was validated in a prostate phantom and evaluated in patients by capturing live US from imaging positions suggested by the visibility map. In 20 liver SABR patients treated with VMAT, the simulation environment was used to virtually place the robotic hardware and US probe. Imaging targets were either planning target volumes (PTVs, range 5.9-679.5 ml) or gross tumor volumes (GTVs, range 0.9-343.4 ml). Presence or absence of mechanical interference with LINAC, couch, and patient body as well as interferences with treated beams was recorded.For PTV targets, robotic US guidance without mechanical interference was possible in 80% of the cases and guidance without beam interference was possible in 60% of the cases. For the smaller GTV targets, these proportions were 95% and 85%, respectively. GTV size (1/20), elongated shape (1/20), and depth (1/20) were the main factors limiting the availability of noninterfering imaging positions. The robotic US imaging system was deployed in two liver SABR patients during CT simulation with successful acquisition of 4D US sequences in different imaging positions.This study indicates that for VMAT liver SABR, robotic US imaging of a relevant internal target may be possible in 85% of the cases while using treatment plans currently deployed in the clinic. With beam replanning to account for the presence of robotic US guidance, intrafractional US may be an option for 95% of the liver SABR cases.

  View details for PubMedID 27806580

• Sonographic Evaluation for Endometrial Polyps: The Interrupted Mucosa Sign. Journal of ultrasound in medicine Kamaya, A., Yu, P. C., Lloyd, C. R., Chen, B. H., Desser, T. S., Maturen, K. E. 2016; 35 (11): 2381-2387

  Abstract

  To evaluate the interrupted mucosa sign for identification of endometrial polyps, using pathologic confirmation as the reference standard, compared to other accepted sonographic findings.We reviewed 195 patients referred for pelvic sonographic evaluations for suspected endometrial polyps in this retrospective Institutional Review Board-approved study. Of these, 82 had tissue sampling of the endometrium and constituted the final study group. Patient data, including age, menopausal status, last menstrual period, and final pathologic diagnosis, were recorded. Sonograms were reviewed by 2 blinded board-certified radiologists for endometrial features, including thickness, echogenicity, vascularity, presence of a mass, and the interrupted mucosa sign. Descriptive statistics and multivariate logistic regression analysis were performed.The mean age of the patients was 44.99 (SD, 9.88) years, 79.1% of whom were premenopausal. Pathologic diagnosis confirmed polyps in 58 (70.73%). A single feeding vessel was visualized in 36 patients with polyps (62.07%), whereas the interrupted mucosa sign was visualized in 34 (58.62%). The presence of a feeding vessel, the interrupted mucosa sign, or both detected 48 (82.76%) of the polyps. In the multivariate analysis, only the interrupted mucosa sign was a statistically significant predictor of pathologic diagnosis of a polyp (P = .035), with an odds ratio of 3.83 (95% confidence interval, 1.10-13.29). Other sonographic findings were not independent predictors of a polyp: mass (P = .35), single feeding vessel (P = .31), endometrial thickness (P = .88), and endometrial echogenicity (P = .45). The sensitivity, specificity, and positive predictive value of the interrupted mucosa sign were 59%, 75%, and 85%, respectively.The interrupted mucosa sign is a promising sonographic sign for identification of endometrial polyps, with greater predictive power than previously described signs. It has the potential to improve the diagnostic performance of sonography, especially when used in combination with other described signs.

  View details for PubMedID 27629758

• Ovarian cancer mimics: how to avoid being fooled by extraovarian pelvic masses ABDOMINAL RADIOLOGY Masch, W. R., Kamaya, A., Wasnik, A. P., Maturen, K. E. 2016; 41 (4): 783-793

  Abstract

  In our clinical experience, pelvic masses from a variety of anatomic sites may be misdiagnosed as ovarian cancer. This tendency to overdiagnose a rare disease probably reflects both its protean imaging appearance and concern for its potential morbidity and mortality. However, radiologists can better serve patients with an analytic approach to the anatomic and tissue features of pelvic masses. We review a range of ovarian cancer mimics and illustrate the radiologic reasoning enabling correct diagnosis.

  View details for DOI 10.1007/s00261-015-0570-1

  View details for Web of Science ID 000374964100020

  View details for PubMedID 26867729

• Duplex Doppler Ultrasound of the Hepatic Artery: A Window to Diagnosis of Diffuse Liver Pathology. Ultrasound quarterly Go, S., Kamaya, A., Jeffrey, B., Desser, T. S. 2016; 32 (1): 58-66

  Abstract

  The use of Doppler sonography for evaluation of the liver is well established, and evaluation of the portal and hepatic veins in native livers, as well as the hepatic artery in transplant livers, is a standard part of the examination. Less well known, however, is that assessment hepatic of artery blood flow velocities and waveforms can permit inferences to be made about liver and system pathophysiology even in native livers. This review will illustrate that hepatic parenchymal abnormalities, as well as primary vascular abnormalities both upstream and downstream of the proper hepatic artery, can be inferred from careful interrogation of its Doppler signature during routine abdominal sonography.

  View details for DOI 10.1097/RUQ.0000000000000166

  View details for PubMedID 26938035

• Diagnostic Ultrasound: Abdomen and Pelvis Kamaya, A., Wong-You-Cheong, J. Elsevier. 2016
• Radiological findings in pelvic solitary fibrous tumour. BJR case reports Johannet, P. n., Kamaya, A. n., Gayer, G. n. 2016; 2 (4): 20150373

  Abstract

  Solitary fibrous tumour (SFT) is an uncommon, usually benign mesenchymal neoplasm. SFT was first described in the pleura, but has subsequently been reported to occur in numerous anatomic locations including the abdomen and pelvis. Abdominopelvic SFTs are typically an indolent process, in spite of reaching a large size by the time of diagnosis. The preferred treatment is complete resection followed by extended follow-up surveillance. The risk of local recurrence and metastasis correlates with tumour size and the histological status of surgical margins. We present the imaging findings of a large pelvic SFT in a 61-year-old female, including ultrasound, CT and MRI.

  View details for PubMedID 30460023

• Sonographic Detection of Extracapsular Extension in Papillary Thyroid Cancer. Journal of ultrasound in medicine Kamaya, A., Tahvildari, A. M., Patel, B. N., Willmann, J. K., Jeffrey, R. B., Desser, T. S. 2015; 34 (12): 2225-2230

  Abstract

  To identify and evaluate sonographic features suggestive of extracapsular extension in papillary thyroid cancer.Three board-certified radiologists blinded to the final pathologic tumor stage reviewed sonograms of pathologically proven cases of papillary thyroid cancer for the presence of extracapsular extension. The radiologists evaluated the following features: capsular abutment, bulging of the normal thyroid contour, loss of the echogenic capsule, and vascularity extending beyond the capsule.A total of 129 cases of pathologically proven thyroid cancer were identified. Of these, 51 were excluded because of lack of preoperative sonography, and 16 were excluded because of pathologic findings showing anaplastic carcinoma, follicular carcinoma, or microcarcinoma (<10 mm). The final analysis group consisted of 62 patients with papillary thyroid carcinoma, 16 of whom had pathologically proven extracapsular extension. The presence of capsular abutment had 100% sensitivity for detection of extracapsular extension. Conversely, lack of capsular abutment had a 100% negative predictive value (NPV) for excluding extracapsular extension. Contour bulging had 88% sensitivity for detection of extracapsular extension and when absent had an 87% NPV. Loss of the echogenic capsule was the best predictor of the presence of extracapsular extension, with an odds ratio of 10.23 (P= .034). This sonographic finding had 75% sensitivity, 65% specificity, and an 88% NPV. Vascularity beyond the capsule had 89% specificity but sensitivity of only 25%.Sonographic features of capsular abutment, contour bulging, and loss of the echogenic thyroid capsule have excellent predictive value for excluding or detecting extracapsular extension and may help in biopsy selection, surgical planning, and treatment of patients with papillary thyroid cancer.

  View details for DOI 10.7863/ultra.15.02006

  View details for PubMedID 26518279

• Variable color Doppler sonographic appearances of retained products of conception: radiologic-pathologic correlation. Abdominal imaging Kamaya, A., Krishnarao, P. M., Folkins, A. K., Jeffrey, R. B., Desser, T. S., Maturen, K. E. 2015; 40 (7): 2683-2689

  Abstract

  Retained products of conception (RPOC) displays variable vascularity, ranging from avascular to markedly vascular on color Doppler sonography. We hypothesize that variability in sonographic vascularity may be due to histopathologic variation in the placental tissue.After institutional review board approval, sonographic images and pathologic specimens were retrospectively reviewed in 26 patients with pathologically proven RPOC. Ultrasound (US) images were scored 0-3 for the degree of vascularity by two radiologists blinded to the diagnosis. Corresponding pathologic specimens were evaluated for vascularization of chorionic villi, degree of inflammation, morphology of maternal arteries, chorionic villous preservation, and percentage of clot, membranes, chorionic villi, and decidua/myometrium. Statistical analysis, including multiple linear regression, was performed.RPOC with histologically avascular chorionic villi or those with markedly reduced vascularization had significantly lower US vascularity scores (p = 0.030) than those with chorionic villi showing normal or decreased vascularization. Sonographically avascular RPOC had a significantly lower percentage villi (p = 0.028) and higher percentage of decidua (p = 0.004) than specimens where US showed any Doppler vascularity. Histologic vascularity of villi (p = 0.049) and non-observation of maternal arteries (p = 0.001) were significant predictors of US vascularity scores in multivariate linear regression analysis, while inflammation of villi (p = 0.053) was a marginally significant predictor.Histologic vascularity of villi appears to contribute to the observed variation in sonographic vascularity. This finding may underlie known differences in clinical outcomes between sonographic vascularity groups.

  View details for DOI 10.1007/s00261-015-0424-x

  View details for PubMedID 25862548

• Core samples for radiomics features that are insensitive to tumor segmentation: method and pilot study using CT images of hepatocellular carcinoma. Journal of medical imaging (Bellingham, Wash.) Echegaray, S., Gevaert, O., Shah, R., Kamaya, A., Louie, J., Kothary, N., Napel, S. 2015; 2 (4): 041011-?

  Abstract

  The purpose of this study is to investigate the utility of obtaining "core samples" of regions in CT volume scans for extraction of radiomic features. We asked four readers to outline tumors in three representative slices from each phase of multiphasic liver CT images taken from 29 patients (1128 segmentations) with hepatocellular carcinoma. Core samples were obtained by automatically tracing the maximal circle inscribed in the outlines. Image features describing the intensity, texture, shape, and margin were used to describe the segmented lesion. We calculated the intraclass correlation between the features extracted from the readers' segmentations and their core samples to characterize robustness to segmentation between readers, and between human-based segmentation and core sampling. We conclude that despite the high interreader variability in manually delineating the tumor (average overlap of 43% across all readers), certain features such as intensity and texture features are robust to segmentation. More importantly, this same subset of features can be obtained from the core samples, providing as much information as detailed segmentation while being simpler and faster to obtain.

  View details for DOI 10.1117/1.JMI.2.4.041011

  View details for PubMedID 26587549

• Atypia of undetermined significance and follicular lesions of undetermined significance: sonographic assessment for prediction of the final diagnosis. Journal of ultrasound in medicine Kamaya, A., Lewis, G. H., Liu, Y., Akatsu, H., Kong, C., Desser, T. S. 2015; 34 (5): 767-774

  Abstract

  To determine whether radiologic assessment of thyroid nodules can potentially help guide clinical management after a cytologic diagnosis of atypia of undetermined significance or a follicular lesion of undetermined significance.We identified 41 patients with 41 thyroid nodules initially diagnosed as atypia or follicular lesions of undetermined significance on fine-needle aspiration that were subsequently definitively diagnosed by either surgical resection or repeated fine-needle aspiration. All sonograms of nodules were reviewed by 2 blinded board-certifiedradiologists. Lesions were assessed in 3 ways: (1) Mayo pattern classification as benign, indeterminate, or worrisome for malignancy (Ultrasound Q 2005; 21:157-165); (2) thyroid imaging reporting and data system scores (scale of 1-5) based on 2 different previously published scoring criteria (Park et al [Thyroid 2009; 19:1257-1264] and Kwak et al [Radiology 2011; 260:892-899]); and (3) binary classification as benign or malignant.Of the 41 nodules, 25 had benign histologic findings, and 16 were malignant. Mayo pattern classification was 100% accurate for the benign score. Lesions with a Mayo score of indeterminate were malignant in 21% of cases (6 of 28) and benign in 79% (22 of 28). Lesions with a Mayo score of malignant were malignant in 91% of cases (10 of 11) and benign in 9% (1 of 11). Thyroid imaging reporting and data system scores had area under the receiver operating characteristic curve values of 0.827 for Park scores and 0.822 for Kwak scores. Radiologist binary classification of thyroid nodules showed 88% overall accuracy.Radiologist assessment of thyroid nodules in cases of atypia of undetermined significance or follicular lesions of undetermined significance is highly predictive of the final diagnosis and can help guide management of thyroid nodules of these pathologic types.

  View details for DOI 10.7863/ultra.34.5.767

  View details for PubMedID 25911708

• Classification of Hypervascular Liver Lesions Based on Hepatic Artery and Portal Vein Blood Supply Coefficients Calculated from Triphasic CT Scans JOURNAL OF DIGITAL IMAGING Boas, F. E., Kamaya, A., Do, B., Desser, T. S., Beaulieu, C. F., Vasanawala, S. S., Hwang, G. L., Sze, D. Y. 2015; 28 (2): 213-223

  Abstract

  Perfusion CT of the liver typically involves scanning the liver at least 20 times, resulting in a large radiation dose. We developed and validated a simplified model of tumor blood supply that can be applied to standard triphasic scans and evaluated whether this can be used to distinguish benign and malignant liver lesions. Triphasic CTs of 46 malignant and 32 benign liver lesions were analyzed. For each phase, regions of interest were drawn in the arterially enhancing portion of each lesion, as well as the background liver, aorta, and portal vein. Hepatic artery and portal vein blood supply coefficients for each lesion were then calculated by expressing the enhancement curve of the lesion as a linear combination of the enhancement curves of the aorta and portal vein. Hepatocellular carcinoma (HCC) and hypervascular metastases, on average, both had increased hepatic artery coefficients compared to the background liver. Compared to HCC, benign lesions, on average, had either a greater hepatic artery coefficient (hemangioma) or a greater portal vein coefficient (focal nodular hyperplasia or transient hepatic attenuation difference). Hypervascularity with washout is a key diagnostic criterion for HCC, but it had a sensitivity of 72 % and specificity of 81 % for diagnosing malignancy in our diverse set of liver lesions. The sensitivity for malignancy was increased to 89 % by including enhancing lesions that were hypodense on all phases. The specificity for malignancy was increased to 97 % (p = 0.039) by also examining hepatic artery and portal vein blood supply coefficients, while maintaining a sensitivity of 76 %.

  View details for DOI 10.1007/s10278-014-9725-9

  View details for Web of Science ID 000351242500012

  View details for PubMedID 25183580

• Atypical thyroid cancers on sonography. Ultrasound quarterly Klang, K., Kamaya, A., Tahvildari, A. M., Jeffrey, R. B., Desser, T. S. 2015; 31 (1): 69-74

  Abstract

  The management of thyroid nodules is a common clinical problem. Thyroid nodules are present in up to 50% of the adult population. However, thyroid malignancy is rare, occurring in only 5% to 15% of nodules. Although certain specific patterns on imaging are almost always indicative of benignity, there is considerable overlap between the sonographic appearances of benign and malignant nodules. Radiologists should be wary of applying pattern recognition approaches too liberally as some malignant nodules may exhibit sonographic features more commonly associated with benign nodules such as cystic change, comet-tail artifact, smooth margins, echogenic echotexture, hypoechoic halos, or peripheral calcifications. This article illustrates atypical imaging appearances of thyroid malignancies and reviews recent literature in an attempt to clarify nuances in the diagnosis of malignancy in benign-appearing nodules.

  View details for DOI 10.1097/RUQ.0000000000000079

  View details for PubMedID 25706368

• Single-versus Multifraction Stereotactic Body Radiation Therapy for Pancreatic Adenocarcinoma: Outcomes and Toxicity INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Pollom, E. L., Alagappan, M., von Eyben, R., Kunz, P. L., Fisher, G. A., Ford, J. A., Poultsides, G. A., Visser, B. C., Norton, J. A., Kamaya, A., Cox, V. L., Columbo, L. A., Koong, A. C., Chang, D. T. 2014; 90 (4): 918-925

  Abstract

  We report updated outcomes of single- versus multifraction stereotactic body radiation therapy (SBRT) for unresectable pancreatic adenocarcinoma.We included 167 patients with unresectable pancreatic adenocarcinoma treated at our institution from 2002 to 2013, with 1-fraction (45.5% of patient) or 5-fraction (54.5% of patients) SBRT. The majority of patients (87.5%) received chemotherapy.Median follow-up was 7.9 months (range: 0.1-63.6). The 6- and 12-month cumulative incidence rates (CIR) of local recurrence for patients treated with single-fraction SBRT were 5.3% (95% confidence interval [CI], 0.2%-10.4%) and 9.5% (95% CI, 2.7%-16.2%), respectively. The 6- and 12-month CIR with multifraction SBRT were 3.4% (95% CI, 0.0-7.2%) and 11.7% (95% CI, 4.8%-18.6%), respectively. Median survival from diagnosis for all patients was 13.6 months (95% CI, 12.2-15.0 months). The 6- and 12- month survival rates from SBRT for the single-fraction group were 67.0% (95% CI, 57.2%-78.5%) and 30.8% (95% CI, 21.9%-43.6%), respectively. The 6- and 12- month survival rates for the multifraction group were 75.7% (95% CI, 67.2%-85.3%) and 34.9% (95% CI, 26.1%-46.8%), respectively. There were no differences in CIR or survival rates between the single- and multifraction groups. The 6- and 12-month cumulative incidence rates of gastrointestinal toxicity grade ≥3 were 8.1% (95% CI, 1.8%-14.4%) and 12.3% (95% CI, 4.7%-20.0%), respectively, in the single-fraction group, and both were 5.6% (95% CI, 0.8%-10.5%) in the multifraction group. There were significantly fewer instances of toxicity grade ≥2 with multifraction SBRT (P=.005). Local recurrence and toxicity grade ≥2 were independent predictors of worse survival.Multifraction SBRT for pancreatic cancer significantly reduces gastrointestinal toxicity without compromising local control.

  View details for DOI 10.1016/j.ijrobp.2014.06.066

  View details for Web of Science ID 000344734300029

• Single- versus multifraction stereotactic body radiation therapy for pancreatic adenocarcinoma: outcomes and toxicity. International journal of radiation oncology, biology, physics Pollom, E. L., Alagappan, M., von Eyben, R., Kunz, P. L., Fisher, G. A., Ford, J. A., Poultsides, G. A., Visser, B. C., Norton, J. A., Kamaya, A., Cox, V. L., Columbo, L. A., Koong, A. C., Chang, D. T. 2014; 90 (4): 918-925

  Abstract

  We report updated outcomes of single- versus multifraction stereotactic body radiation therapy (SBRT) for unresectable pancreatic adenocarcinoma.We included 167 patients with unresectable pancreatic adenocarcinoma treated at our institution from 2002 to 2013, with 1-fraction (45.5% of patient) or 5-fraction (54.5% of patients) SBRT. The majority of patients (87.5%) received chemotherapy.Median follow-up was 7.9 months (range: 0.1-63.6). The 6- and 12-month cumulative incidence rates (CIR) of local recurrence for patients treated with single-fraction SBRT were 5.3% (95% confidence interval [CI], 0.2%-10.4%) and 9.5% (95% CI, 2.7%-16.2%), respectively. The 6- and 12-month CIR with multifraction SBRT were 3.4% (95% CI, 0.0-7.2%) and 11.7% (95% CI, 4.8%-18.6%), respectively. Median survival from diagnosis for all patients was 13.6 months (95% CI, 12.2-15.0 months). The 6- and 12- month survival rates from SBRT for the single-fraction group were 67.0% (95% CI, 57.2%-78.5%) and 30.8% (95% CI, 21.9%-43.6%), respectively. The 6- and 12- month survival rates for the multifraction group were 75.7% (95% CI, 67.2%-85.3%) and 34.9% (95% CI, 26.1%-46.8%), respectively. There were no differences in CIR or survival rates between the single- and multifraction groups. The 6- and 12-month cumulative incidence rates of gastrointestinal toxicity grade ≥3 were 8.1% (95% CI, 1.8%-14.4%) and 12.3% (95% CI, 4.7%-20.0%), respectively, in the single-fraction group, and both were 5.6% (95% CI, 0.8%-10.5%) in the multifraction group. There were significantly fewer instances of toxicity grade ≥2 with multifraction SBRT (P=.005). Local recurrence and toxicity grade ≥2 were independent predictors of worse survival.Multifraction SBRT for pancreatic cancer significantly reduces gastrointestinal toxicity without compromising local control.

  View details for DOI 10.1016/j.ijrobp.2014.06.066

  View details for PubMedID 25585785

• CT Perfusion of the Liver: Principles and Applications in Oncology. Radiology Kim, S. H., Kamaya, A., Willmann, J. K. 2014; 272 (2): 322-344

  Abstract

  With the introduction of molecularly targeted chemotherapeutics, there is an increasing need for defining new response criteria for therapeutic success because use of morphologic imaging alone may not fully assess tumor response. Computed tomographic (CT) perfusion imaging of the liver provides functional information about the microcirculation of normal parenchyma and focal liver lesions and is a promising technique for assessing the efficacy of various anticancer treatments. CT perfusion also shows promising results for diagnosing primary or metastatic tumors, for predicting early response to anticancer treatments, and for monitoring tumor recurrence after therapy. Many of the limitations of early CT perfusion studies performed in the liver, such as limited coverage, motion artifacts, and high radiation dose of CT, are being addressed by recent technical advances. These include a wide area detector with or without volumetric spiral or shuttle modes, motion correction algorithms, and new CT reconstruction technologies such as iterative algorithms. Although several issues related to perfusion imaging-such as paucity of large multicenter trials, limited accessibility of perfusion software, and lack of standardization in methods-remain unsolved, CT perfusion has now reached technical maturity, allowing for its use in assessing tumor vascularity in larger-scale prospective clinical trials. In this review, basic principles, current acquisition protocols, and pharmacokinetic models used for CT perfusion imaging of the liver are described. Various oncologic applications of CT perfusion of the liver are discussed and current challenges, as well as possible solutions, for CT perfusion are presented. © RSNA, 2014 Online supplemental material is available for this article.

  View details for DOI 10.1148/radiol.14130091

  View details for PubMedID 25058132

• A multicenter phase II study of pazopanib in patients with advanced gastrointestinal stromal tumors (GIST) following failure of at least imatinib and sunitinib. Annals of oncology Ganjoo, K. N., Villalobos, V. M., Kamaya, A., Fisher, G. A., Butrynski, J. E., Morgan, J. A., Wagner, A. J., D'adamo, D., McMillan, A., Demetri, G. D., George, S. 2014; 25 (1): 236-240

  Abstract

  Advanced GISTs are incurable, but often treatable for years with tyrosine kinase inhibitors (TKIs). The majority of GISTs harbor an oncogenic activating mutation in KIT or PDGFRA. Inhibition of this activating mutation with TKIs most often leads to durable disease control for many patients. However, almost all patients develop resistance to these TKIs, typically due to the development of secondary mutations, heralding the need for new therapeutic options. We conducted a phase II study evaluating the efficacy and toxicity of pazopanib, a broad spectrum TKI inhibiting KIT, VEGFRs (-1, -2, and -3), and PDGFR (-α and-β) in patients with advanced GIST following failure of at least imatinib and sunitinib.Patients received pazopanib 800 mg orally once daily. All patients were assessed for efficacy with CT scans every 8 weeks (two cycles). Patients continued pazopanib until progression or unacceptable toxicity. The primary end point was the 24-week nonprogression [complete response+partial response+stable disease (SD)] rate (NPR) per RECIST 1.1. Secondary end points included PFS, OS, and toxicity.Between August 2011 and September 2012, a total of 25 patients were treated at two institutions. Median number of prior therapy was 3 (range 2-7). A total of 90 cycles of pazopanib were administered, with a median of two cycles (range 1 to 17+) per patient. Best response of SD at any time was observed in 12 (48%) patients. The NPR was 17% [95% confidence interval (CI) 4.5-37]. All but one patient discontinued protocol either due to PD (n = 19) or intolerance (n = 4). One patient with succinate dehydrogenase (SDH)-deficient GIST exhibited continuing disease control after 17 cycles. The median PFS for the entire cohort was 1.9 months (95% CI 1.6-5.2), and the median OS was 10.7 months (95% CI 3.9-NR).Pazopanib was reasonably well tolerated with no unexpected toxicities. Pazopanib as a single agent has marginal activity in unselected heavily pretreated patients with advanced GIST.

  View details for DOI 10.1093/annonc/mdt484

  View details for PubMedID 24356634

• The elusive parathyroid adenoma: techniques for detection. Ultrasound quarterly Devcic, Z., Jeffrey, R. B., Kamaya, A., Desser, T. S. 2013; 29 (3): 179-187

  Abstract

  The success of minimally invasive surgery for hyperparathyroidism depends on accurate preoperative localization of the hyperfunctioning adenoma with imaging. Ultrasound is an excellent initial modality because it has a high positive predictive value, sensitivity, and specificity, while being inexpensive and noninvasive without use of ionizing radiation. Determining the exact location and number of adenomas is essential, because these factors guide the surgical approach. The goal of this review article was to discuss specific sonographic techniques that can be applied to find even the elusive adenoma, which include (1) compression scanning, (2) color Doppler, (3) scanning regions where ectopic glands may be located, and (4) evaluating intrathyroidal adenomas.

  View details for DOI 10.1097/RUQ.0b013e3182a1ba6f

  View details for PubMedID 23975046

• Photoacoustic imaging of the bladder: a pilot study. Journal of ultrasound in medicine Kamaya, A., Vaithilingam, S., Chung, B. I., Oralkan, O., Khuri-Yakub, B. T. 2013; 32 (7): 1245-1250

  Abstract

  Photoacoustic imaging is a promising new technology that combines tissue optical characteristics with ultrasound transmission and can potentially visualize tumor depth in bladder cancer. We imaged simulated tumors in 5 fresh porcine bladders with conventional pulse-echo sonography and photoacoustic imaging. Isoechoic biomaterials of different optical qualities were used. In all 5 of the bladder specimens, photoacoustic imaging showed injected biomaterials, containing varying degrees of pigment, better than control pulse-echo sonography. Photoacoustic imaging may be complementary to diagnostic information obtained by cystoscopy and urine cytologic analysis and could potentially obviate the need for biopsy in some tumors before definitive treatment.

  View details for DOI 10.7863/ultra.32.7.1245

  View details for PubMedID 23804347

• New Technologies in Clinical Ultrasound SEMINARS IN ROENTGENOLOGY Kamaya, A., Machtaler, S., Sanjani, S. S., Nikoozadeh, A., Sommer, F. G., Khuri-Yakub, B. T., Willmann, J. K., Desser, T. S. 2013; 48 (3): 214-223

  View details for DOI 10.1053/j.ro.2013.03.009

  View details for Web of Science ID 000321602300005

• Pitfalls in sonographic evaluation of thyroid abnormalities. Seminars in ultrasound, CT, and MR Patel, B. N., Kamaya, A., Desser, T. S. 2013; 34 (3): 226-235

  Abstract

  Ultrasound of the thyroid has become increasingly common, with evaluation of thyroid nodules representing the main indication for its use. While detection of thyroid nodules with modern high-resolution sonographic equipment is generally not a challenge, pitfalls may occur by which normal structures or pathology in neighboring organs are mistaken for thyroid nodules. Numerous reports in the literature describe various sonographic features of nodules in an attempt to stratify lesions into benign or malignant categories. While neither nodule size nor number is reliable, echogenicity, microcalcifcation, shape, and composition have been reported to be helpful in classifying thyroid nodules. No single feature should be used in isolation, and consensus guidelines have been established as to when fine-needle aspiration is indicated. Pitfalls remain in the evaluation of thyroid nodules demonstrating atypical features, such as cystic papillary carcinomas. Focal presentation of typically diffuse processes, such as Graves' disease and Hashimoto thyroiditis, may mimic malignant nodules, but carcinomas occur in these settings as well as in a background of normal thyroid parenchyma. Finally, because ultrasound is commonly used for surveillance of patients with thyroid carcinoma after thyroidectomy, sonographers should be familiar with the ultrasound appearance of disease recurrence and its mimics.

  View details for DOI 10.1053/j.sult.2012.11.001

  View details for PubMedID 23768889

• Physiologic, histologic, and imaging features of retained products of conception. Radiographics Sellmyer, M. A., Desser, T. S., Maturen, K. E., Jeffrey, R. B., Kamaya, A. 2013; 33 (3): 781-796

  Abstract

  Retained products of conception (RPOC) are a common and treatable complication after delivery or termination of pregnancy. The pathologic diagnosis of RPOC is made based on the presence of chorionic villi, which indicates persistent placental or trophoblastic tissue. In the setting of postpartum hemorrhage, however, distinguishing RPOC from bleeding related to normal postpartum lochia or uterine atony can be clinically challenging. Ultrasonographic (US) evaluation can be particularly helpful in these patients, and a thickened endometrial echo complex (EEC) or a discrete mass in the uterine cavity is a helpful gray-scale US finding that suggests RPOC. However, gray-scale US findings alone are inadequate for accurate diagnosis. Detection of vascularity in a thickened EEC or an endometrial mass at color or power Doppler US increases the positive predictive value for the diagnosis of RPOC. Computed tomography or magnetic resonance imaging may be helpful when US findings are equivocal and typically demonstrates an enhancing intracavitary mass in patients with RPOC. Diagnostic pitfalls are rare but may include highly vascular RPOC, which can be mistaken for a uterine arteriovenous malformation; true arteriovenous malformations of the uterus; invasive moles; blood clot; and subinvolution of the placental implantation site. © RSNA, 2013.

  View details for DOI 10.1148/rg.333125177

  View details for PubMedID 23674774

• Aortoenteric fistulas: spectrum of CT findings ABDOMINAL IMAGING Raman, S. P., Kamaya, A., Federle, M., Fishman, E. K. 2013; 38 (2): 367-375

  Abstract

  This article reviews the causes of aortoenteric fistulas, diagnostic options, and important CT findings.Aortoenteric fistula, a rare but potentially fatal entity, presents a significant challenge to radiologists in diagnosis, largely because of its subtle and nonspecific imaging findings. These fistulas can be divided into primary and secondary forms, depending on the presence or absence of prior aortic reconstructive surgery, but the secondary form is more common. Typical CT findings, which can overlap with those seen in perigraft infection, aortitis, infected/mycotic aneurysms, perianeurysmal fibrosis, and the immediate post-operative period after placement of a graft, include: Effacement of the fat planes around the aorta, perigraft fluid/soft tissue thickening, ectopic gas, tethering of adjacent thickened bowel loops towards the aortic graft, and in rare cases, extravasation of contrast from the aorta into the involved segment of bowel.

  View details for DOI 10.1007/s00261-012-9873-7

  View details for Web of Science ID 000316144100019

  View details for PubMedID 22366854

• Quantitatively Defining Washout in Hepatocellular Carcinoma AMERICAN JOURNAL OF ROENTGENOLOGY Liu, Y. I., Shin, L. K., Jeffrey, R. B., Kamaya, A. 2013; 200 (1): 84-89

  Abstract

  Washout on delayed phase (or equilibrium phase) imaging of an arterially hyperenhancing lesion is an excellent predictor of hepatocellular carcinoma (HCC). The purpose of our study was to quantitatively define washout in pathologically proven HCC. A quantitative definition of HCC may minimize interobserver variability and facilitate more accurate diagnosis.We identified 47 liver lesions that were hyperenhancing in the arterial phase from 24 patients who underwent triphasic MDCT as part of preoperative evaluation for liver transplantation. All HCCs were pathologically proven. Regions of interest were obtained of lesions and areas of adjacent liver on arterial, portal venous, and delayed phase images. Enhancement profiles were assessed by three radiologists.Of the 47 hypervascular lesions, 14 HCCs were identified. There was a statistically significant difference in percentage attenuation ratio (defined as 100 × ratio of attenuation of adjacent liver to that of the lesion) between lesions that were HCC (median percentage attenuation ratio, 121) and those that were not (median percentage attenuation ratio, 101) on delayed phase. Percentage attenuation ratio ≥ 107 on delayed phase imaging achieved maximal sensitivity (100%) with good specificity (75.8%), positive predictive value (PPV) (63.6%), and negative predictive value (NPV) (100%) in HCC detection. Percentage attenuation ratio also correlated well with radiologists' assessments of enhancement profiles of lesions (multinomial logistic regression McFadden R(2), 0.72; chi-square p, < 0.01).Our analysis of simple CT attenuation measurements indicates that percentage attenuation ratio offers excellent sensitivity, specificity, PPV, and NPV for HCC detection and very good correlation with radiologists' assessments of washout.

  View details for DOI 10.2214/AJR.11.7171

  View details for PubMedID 23255745

• Positron Emission Tomography for Predicting Pathologic Response After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Cancer 50th Annual Meeting of the American-Society-for-Therapeutic-Radiation-Oncology (ASTRO) Chennupati, S. K., Quon, A., Kamaya, A., Pai, R. K., La, T., Krakow, T. E., Graves, E., Koong, A. C., Chang, D. T. LIPPINCOTT WILLIAMS & WILKINS. 2012: 334–39

  Abstract

  To investigate whether before and after chemoradiotherapy (CRT) positron emission tomography (PET) predict for pathologic response after preoperative CRT in patients with locally advanced rectal adenocarcinoma.Thirty-five patients who underwent pre-CRT and post-CRT PET scans before surgery were included. All patients were staged with endoscopic ultrasound or high resolution CT. CRT was given with 50.4 Gy at 1.8 Gy per fraction and concurrent 5-fluorouracil-based chemotherapy. Surgery occurred at a median of 46 days (range, 27 to 112 d) after completing CRT. The maximum standardized uptake value (SUV(max)) and the metabolic tumor volume (MTV) using various minimum SUV thresholds (2, 2.5, 3) on the PET scans (MTV(2.0), MTV(2.5), MTV(3.0)) were determined. Post-CRT PET scans were done 3 to 5 weeks after completion of CRT. Pathologic response was assessed using the tumor regression grade (TRG) scale. Patients with complete or near-complete response (TRG=0 to 1) were considered pathologic responders. The pre-CRT and post-CRT PET scan SUV(max) and MTV values were correlated with TRG. The ΔSUV(max) and ΔMTV were correlated with TRG.No correlation was seen with SUV(max) (P=0.99), MTV(2.0) (P=0.73), MTV(2.5) (P=0.73), or MTV(3.0) (P=0.31) on the pre-CRT PET between pathologic responders versus nonresponders. No correlation was noted between SUV(max) (P=0.49), MTV(2.0) (P=0.73), MTV(2.5) (P=0.49), or MTV(3.0) (P=0.31) on the post-CRT PET scan and pathologic response. Finally, the ΔSUV(max) (P=0.32), ΔMTV(2.0) (P=0.99), ΔMTV(2.5) (P=0.31), ΔMTV(3.0) (P=0.31) did not correlate with pathologic response.Changes seen on PET have limited value in predicting for pathologic response of rectal cancer after preoperative neoadjuvant therapy.

  View details for DOI 10.1097/COC.0b013e3182118d12

  View details for PubMedID 21422989

• Multidetector Computed Tomography Triphasic Evaluation of the Liver Before Transplantation: Importance of Equilibrium Phase Washout and Morphology for Characterizing Hypervascular Lesions JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Liu, Y. I., Kamaya, A., Jeffrey, R. B., Shin, L. K. 2012; 36 (2): 213-219

  Abstract

  We aim to identify the sensitivity and positive predictive value (PPV) of arterial phase imaging in detecting hepatocellular carcinoma (HCC) and determine the added value of portal venous and equilibrium phase imaging and lesion morphology characterization.We reviewed all patients who underwent liver transplantation at our institution that had a triphasic multidetector computed tomography examination within 6 months of transplantation. Forty-seven hypervascular lesions were identified in 24 patients. Imaging findings were correlated with explant pathologic correlation.Hypervascularity in the arterial phase resulted in sensitivity of 87.5% and PPV of 29.8%. The presence of washout in the equilibrium phase increased the PPV to 92.9% with a slight decrease in sensitivity (81.3%). The negative predictive value of hypervascular lesions without washout in the equilibrium phase was 97.1%. There was significant correlation between larger lesions and HCC and between round lesions and HCC.The presence of washout in the equilibrium phase is a better indicator of malignancy.

  View details for DOI 10.1097/RCT.0b013e318247c8f0

  View details for PubMedID 22446362

• Photoacoustic Imaging Using a 9F MicroLinear CMUT ICE Catheter IEEE International Ultrasonics Symposium (IUS) Nikoozadeh, A., Choe, J. W., Kothapalli, S., Moini, A., Sanjani, S. S., Kamaya, A., Oralkan, O., Gambhir, S. S., Khuri-Yakub, P. T. IEEE. 2012: 24–27

  View details for DOI 10.1109/ULTSYM.2012.0007

  View details for Web of Science ID 000326960200006

• Ultrasound Imaging of Bowel Pathology: Technique and Keys to Diagnosis in the Acute Abdomen AMERICAN JOURNAL OF ROENTGENOLOGY Maturen, K. E., Wasnik, A. P., Kamaya, A., Dillman, J. R., Kaza, R. K., Pandya, A., Maheshwary, R. K. 2011; 197 (6): W1067-W1075

  Abstract

  This article illustrates the normal and pathologic sonographic appearances of bowel, with an emphasis on diagnostic ultrasound techniques.The current role of ultrasound for adult bowel evaluation is limited in the United States, with CT emerging as the primary modality for evaluation of the acute abdomen. However, mounting concerns regarding diagnostic radiation and health care costs may affect practice patterns and shift utilization back toward sonography, which is widely available and relatively inexpensive.

  View details for DOI 10.2214/AJR.11.6594

  View details for Web of Science ID 000297369900014

  View details for PubMedID 22109321

• Imaging Manifestations of Abdominal Fat Necrosis and Its Mimics RADIOGRAPHICS Kamaya, A., Federle, M. P., Desser, T. S. 2011; 31 (7): 2021-2034

  Abstract

  Intraabdominal fat is a metabolically active tissue that may undergo necrosis through a number of mechanisms. Fat necrosis is a common finding at abdominal cross-sectional imaging, and it may cause abdominal pain, mimic findings of acute abdomen, or be asymptomatic and accompany other pathophysiologic processes. Common processes that are present in fat necrosis include torsion of an epiploic appendage, infarction of the greater omentum, and fat necrosis related to trauma or pancreatitis. In addition, other pathologic processes that involve fat may be visualized at computed tomography, including focal lipohypertrophy, pathologic fat paucity (lipodystrophies), and malignancies such as liposarcoma, which may mimic benign causes of fat stranding. Because fat necrosis and malignant processes such as liposarcoma and peritoneal carcinomatosis may mimic one another, knowledge of a patient's clinical history and prior imaging studies is essential for accurate diagnosis.

  View details for DOI 10.1148/rg.317115046

  View details for PubMedID 22084185

• A Bayesian Network for Differentiating Benign From Malignant Thyroid Nodules Using Sonographic and Demographic Features AMERICAN JOURNAL OF ROENTGENOLOGY Liu, Y. I., Kamaya, A., Desser, T. S., Rubin, D. L. 2011; 196 (5): W598-W605

  Abstract

  The objective of our study was to create a Bayesian network (BN) that incorporates a multitude of imaging features and patient demographic characteristics to guide radiologists in assessing the likelihood of malignancy in suspicious-appearing thyroid nodules.We built a BN to combine multiple indicators of the malignant potential of thyroid nodules including both imaging and demographic factors. The imaging features and conditional probabilities relating those features to diagnoses were compiled from an extensive literature review. To evaluate our network, we randomly selected 54 benign and 45 malignant nodules from 93 adult patients who underwent ultrasound-guided biopsy. The final diagnosis in each case was pathologically established. We compared the performance of our network with that of two radiologists who independently evaluated each case on a 5-point scale of suspicion for malignancy. Probability estimates of malignancy from the BN and radiologists were compared using receiver operating characteristic (ROC) analysis.The network performed comparably to the two expert radiologists. Using each radiologist's assessment of the imaging features as input to the network, the differences between the area under the ROC curve (A(z)) for the BN and for the radiologists were -0.03 (BN vs radiologist 1, 0.85 vs 0.88) and -0.01 (BN vs radiologist 2, 0.76 vs 0.77).We created a BN that incorporates a range of sonographic and demographic features and provides a probability about whether a thyroid nodule is benign or malignant. The BN distinguished between benign and malignant thyroid nodules as well as the expert radiologists did.

  View details for DOI 10.2214/AJR.09.4037

  View details for PubMedID 21512051

• Hepatic Epithelioid Hemangioendothelioma DIGESTIVE DISEASES AND SCIENCES Liu, Y. I., Brown, S. S., Elihu, A., Bonham, C. A., Concepcion, W., Longacre, T. A., Kamaya, A. 2011; 56 (2): 303-306

  View details for DOI 10.1007/s10620-010-1470-4

  View details for PubMedID 21053076

• Recurrence in the Thyroidectomy Bed: Sonographic Findings AMERICAN JOURNAL OF ROENTGENOLOGY Kamaya, A., Gross, M., Akatsu, H., Jeffrey, R. B. 2011; 196 (1): 66-70

  Abstract

  The purpose of this article is to characterize sonographic features of differentiated thyroid cancer recurrence in the thyroidectomy bed.Patients referred for biopsy of thyroidectomy bed lesions between February 2006 and December 2009 were identified. Patient data and gray-scale and color Doppler features were recorded.Results of ultrasound-guided biopsies of 30 nodules in 27 patients were reviewed. Twenty-five lesions yielded diagnostic findings, including 22 recurrences in 19 patients and three benign lesions in three patients. Five biopsies were nondiagnostic. Among the 22 recurrences, 21 (95%) were hypoechoic and one (5%) was mixed hypoechoic and hyperechoic on gray-scale imaging. On Doppler imaging, 100% of recurrences had detectable vascularity. Eight lesions (36%) had microcalcifications, and five (23%) had coarse calcifications; the average long-axis dimension was 1.5 cm. Of the five nondiagnostic lesions, four (80%) were hypoechoic, one (20%) was isoechoic, one (20%) had microcalcifications, none had coarse calcifications, and two (40%) had vascularity; the average long-axis dimension was 0.6 cm. Of the negative lesions, three (100%) were hypoechoic, two (66%) had vascularity, and two (66%) had coarse calcifications. No microcalcifications were seen, and the average long-axis dimension was 2 cm. Serum thyroglobulin (Tg) or anti-Tg antibodies were elevated in 12 (63%) of 19 patients with recurrence (eight [42%] with elevated Tg levels and four [21%] with elevated anti-Tg antibody levels).An ultrasound finding of a hypoechoic thyroidectomy bed lesion with internal vascularity and size greater than 6 mm is highly sensitive in predicting recurrence. Serum Tg levels were less sensitive than ultrasound in detection of recurrence in the thyroidectomy bed.

  View details for DOI 10.2214/AJR.10.4474

  View details for Web of Science ID 000286018800009

  View details for PubMedID 21178048

• Informatics in Radiology RADTF: A Semantic Search-enabled, Natural Language Processor-generated Radiology Teaching File RADIOGRAPHICS Do, B. H., Wu, A., Biswal, S., Kamaya, A., Rubin, D. L. 2010; 30 (7): 2039-2048

  Abstract

  Storing and retrieving radiology cases is an important activity for education and clinical research, but this process can be time-consuming. In the process of structuring reports and images into organized teaching files, incidental pathologic conditions not pertinent to the primary teaching point can be omitted, as when a user saves images of an aortic dissection case but disregards the incidental osteoid osteoma. An alternate strategy for identifying teaching cases is text search of reports in radiology information systems (RIS), but retrieved reports are unstructured, teaching-related content is not highlighted, and patient identifying information is not removed. Furthermore, searching unstructured reports requires sophisticated retrieval methods to achieve useful results. An open-source, RadLex(®)-compatible teaching file solution called RADTF, which uses natural language processing (NLP) methods to process radiology reports, was developed to create a searchable teaching resource from the RIS and the picture archiving and communication system (PACS). The NLP system extracts and de-identifies teaching-relevant statements from full reports to generate a stand-alone database, thus converting existing RIS archives into an on-demand source of teaching material. Using RADTF, the authors generated a semantic search-enabled, Web-based radiology archive containing over 700,000 cases with millions of images. RADTF combines a compact representation of the teaching-relevant content in radiology reports and a versatile search engine with the scale of the entire RIS-PACS collection of case material.

  View details for DOI 10.1148/rg.307105083

  View details for Web of Science ID 000284094200021

  View details for PubMedID 20801868

• 3-D Deep Penetration Photoacoustic Imaging with a 2-D CMUT Array. Proceedings. IEEE Ultrasonics Symposium Ma, T., Kothapalli, S. R., Vaithilingam, S., Oralkan, O., Kamaya, A., Wygant, I. O., Zhuang, X., Gambhir, S. S., Jeffrey, R. B., Khuri-Yakub, B. T. 2010; 2010: 375-377

  Abstract

  In this work, we demonstrate 3-D photoacoustic imaging of optically absorbing targets embedded as deep as 5 cm inside a highly scattering background medium using a 2-D capacitive micromachined ultrasonic transducer (CMUT) array with a center frequency of 5.5 MHz. 3-D volumetric images and 2-D maximum intensity projection images are presented to show the objects imaged at different depths. Due to the close proximity of the CMUT to the integrated frontend circuits, the CMUT array imaging system has a low noise floor. This makes the CMUT a promising technology for deep tissue photoacoustic imaging.

  View details for PubMedID 22977296

• Pathological response after chemoradiation for T3 rectal cancer COLORECTAL DISEASE Chennupati, S. K., Kamaya, A., Fisher, G. A., Ford, J. M., Kunz, P., Itakura, H., Welton, M. L., Shelton, A., Van Dam, J., Koong, A. C., Chang, D. T. 2010; 12 (7): E24-E30

  Abstract

  The aim of this study was to investigate the effect of preoperative chemoradiotherapy (CRT) on nodal disease in locally advanced rectal adenocarcinoma.Thirty-two patients staged uT3N0 and 27 patients staged uT3N1 rectal adenocarcinoma who underwent pre-CRT staging using endoscopic ultrasound or rectal protocol CT were included. The median radiation dose was 50.4 Gy (range: 45-50.4 Gy) at 1.8 Gy per fraction and all patients received concurrent 5-FU or capecitabine-based chemotherapy. Low anterior resection or abdomino-perineal resection occurred at a median of 46 days (range: 27-112 days) after CRT.Eleven of 32 uT3N0 patients (34.4%) and 13 of 26 uT3N1 patients (50.0%) had ypN+ (P = 0.29). For patients with uT3N0, 10 of 20 (50.0%) with ypT2-3 and 1 of 12 (8.3%) with ypT0-1 were ypN+ (P = 0.02). For patients with uT3N1, 12 of 20 (60.0%) with ypT2-3 and 1 of 6 (16.7%) with ypT0-1 were ypN+ (P = 0.16). Overall, the ypN+ rate was 11.1% in the ypT0-yT1 group compared with 55.0% in the ypT2-yT3 group (P = 003). Among patients with uT3N0 disease, the ypN+ rate in patients who had surgery > 46 days vs 46 days vs 46 days vs

  View details for DOI 10.1111/j.1463-1318.2009.02013.x

  View details for Web of Science ID 000208355900003

• Interpatient Variability of Enhancement of Five Abdominal Organs in Triphasic MDCT 110th Annual Meeting of the American-Roentgen-Ray-Society Liu, Y., Shin, L., Jeffrey, R., Kamaya, A. AMER ROENTGEN RAY SOC. 2010

  View details for Web of Science ID 000276931000203

• A Systemic Search for Patterns for Thyroid Nodule Evaluation Using a Bayesian Classifier 110th Annual Meeting of the American-Roentgen-Ray-Society Liu, Y., Kamaya, A., Desser, T., Rubin, D. AMER ROENTGEN RAY SOC. 2010

  View details for Web of Science ID 000276931000178

• Learning a Bayesian Classifier for Thyroid Nodule Evaluation 110th Annual Meeting of the American-Roentgen-Ray-Society Liu, Y., Kamaya, A., Desser, T., Rubin, D. AMER ROENTGEN RAY SOC. 2010

  View details for Web of Science ID 000276931000177

• What Defines Hepatic "Washout" in Triphasic MDCT? 110th Annual Meeting of the American-Roentgen-Ray-Society Liu, Y., Shin, I., Jeffrey, R., Kamaya, A. AMER ROENTGEN RAY SOC. 2010

  View details for Web of Science ID 000276931000090

• Three-Dimensional Photoacoustic Imaging Using a Two-Dimensional CMUT Array IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL Vaithilingam, S., Ma, T., Furukawa, Y., Wygant, I. O., Zhuang, X., de la Zerda, A., Oralkan, O., Kamaya, A., Gambhir, S. S., Jeffrey, R. B., Khuri-Yakub, B. T. 2009; 56 (11): 2411-2419

  Abstract

  In this paper, we describe using a 2-D array of capacitive micromachined ultrasonic transducers (CMUTs) to perform 3-D photoacoustic and acoustic imaging. A tunable optical parametric oscillator laser system that generates nanosecond laser pulses was used to induce the photoacoustic signals. To demonstrate the feasibility of the system, 2 different phantoms were imaged. The first phantom consisted of alternating black and transparent fishing lines of 180 mum and 150 mum diameter, respectively. The second phantom comprised polyethylene tubes, embedded in chicken breast tissue, filled with liquids such as the dye indocyanine green, pig blood, and a mixture of the 2. The tubes were embedded at a depth of 0.8 cm inside the tissue and were at an overall distance of 1.8 cm from the CMUT array. Two-dimensional cross-sectional slices and 3-D volume rendered images of pulse-echo data as well as photoacoustic data are presented. The profile and beamwidths of the fishing line are analyzed and compared with a numerical simulation carried out using the Field II ultrasound simulation software. We investigated using a large aperture (64 x 64 element array) to perform photoacoustic and acoustic imaging by mechanically scanning a smaller CMUT array (16 x 16 elements). Two-dimensional transducer arrays overcome many of the limitations of a mechanically scanned system and enable volumetric imaging. Advantages of CMUT technology for photoacoustic imaging include the ease of integration with electronics, ability to fabricate large, fully populated 2-D arrays with arbitrary geometries, wide-bandwidth arrays and high-frequency arrays. A CMUT based photoacoustic system is proposed as a viable alternative to a piezoelectric transducer based photoacoustic systems.

  View details for DOI 10.1109/TUFFC.2009.1329

  View details for Web of Science ID 000271478600010

  View details for PubMedID 19942528

• Hypervascular Liver Lesions SEMINARS IN ULTRASOUND CT AND MRI Kamaya, A., Maturen, K. E., Tye, G. A., Liu, Y. I., Parti, N. N., Desser, T. S. 2009; 30 (5): 387-407

  Abstract

  Hypervascular hepatocellular lesions include both benign and malignant etiologies. In the benign category, focal nodular hyperplasia and adenoma are typically hypervascular. In addition, some regenerative nodules in cirrhosis may be hypervascular. Malignant hypervascular primary hepatocellular lesions include hepatocellular carcinoma, fibrolamellar carcinoma, and peripheral cholangiocarcinoma. Vascular liver lesions often appear hypervascular because they tend to follow the enhancement of the blood pool; these include hemangiomas, arteriovenous malformations, angiosarcomas, and peliosis. While most gastrointestinal malignancies that metastasize to the liver will appear hypovascular on arterial and portal-venous phase imaging, certain cancers such as metastatic neuroendocrine tumors (including pancreatic neuroendocrine tumors, carcinoid, and gastrointestinal stromal tumors) tend to produce hypervascular metastases due to the greater recruitment of arterial blood supply. Finally, rare hepatic lesions such as glomus tumor and inflammatory pseudotumor may have a hypervascular appearance.

  View details for DOI 10.1053/j.sult.2009.06.001

  View details for PubMedID 19842564

• Imaging and Diagnosis of Postpartum Complications Sonography and Other Imaging Modalities ULTRASOUND QUARTERLY Kamaya, A., Ro, K., Benedetti, N. J., Chang, P. L., Desser, T. S. 2009; 25 (3): 151-162

  Abstract

  Postpartum complications can be broadly divided into 4 categories: postpartum hemorrhage, obstetrical trauma, thromboembolic complications, and puerperal infections. Postpartum hemorrhage is most commonly caused by uterine atony, abnormal placentation, or genital tract trauma. Secondary causes of hemorrhage include retained products of conception and, rarely, subinvolution of the placental implantation site. Uterine dehiscence or rupture may be occult on ultrasound examination and may be better visualized on sagittal computed tomography or magnetic resonance imaging. Obstetric trauma during prolonged vaginal or cesarean delivery may lead to fistula formation, ureteral injury, or bowel injury. Later potential complications of cesarean delivery include cesarean delivery scar ectopic, endometrial implants in the cesarean scar, and placenta accreta. Thromboembolic complications can include pulmonary embolism and deep vein thrombosis as well as ovarian vein thrombosis, the latter of which can be difficult to clinically differentiate from appendicitis in the postpartum female.

  View details for PubMedID 19730078

• Retained Products of Conception Spectrum of Color Doppler Findings JOURNAL OF ULTRASOUND IN MEDICINE Kamaya, A., Petrovitch, I., Chen, B., Frederick, C. E., Jeffrey, R. B. 2009; 28 (8): 1031-1041

  Abstract

  The purpose of this study was to characterize color Doppler imaging features of retained products of conception (RPOC) with gray scale correlation.Clinically suspected cases of RPOC between January 2005 and February 2008 were reviewed. Patient data and relevant color Doppler and gray scale features were recorded.A total of 269 patients referred for sonographic evaluation for RPOC were identified. Thirty-five patients had confirmed pathologic diagnoses, 28 of whom had RPOC. In those with RPOC, 5 (18%) were avascular (type 0); 6 (21%) had minimal vascularity (type 1); 12 (43%) had moderate vascularity (type 2); and 5 (18%) had marked vascularity (type 3). Peak systolic velocities ranged from 10 to 108 cm/s (average, 36.1 cm/s). Resistive indices in arterial waveforms ranged from 0.33 to 0.7 (average, 0.5). Five (45%) of the patients with type 0 vascularity had RPOC; 6 (86%) of those with type 1 had RPOC; and 17 (100%) of those with types 2 and 3 had RPOC. An echogenic mass had a moderate positive predictive value (80%) but low sensitivity (29%) for RPOC.Color Doppler evaluation of the endometrium is helpful in determining the presence of RPOC. Endometrial vascularity is highly correlated with RPOC, whereas the lack of vascularity can be seen in both intrauterine clots and avascular RPOC.

  View details for Web of Science ID 000268556800008

  View details for PubMedID 19643786

• Laparoscopic radical nephrectomy after shrinkage of a caval tumor thrombus with sunitinib NATURE REVIEWS UROLOGY Harshman, L. C., Srinivas, S., Kamaya, A., Chung, B. I. 2009; 6 (6): 338-343

  Abstract

  A 57-year-old woman presented to the emergency department at a community hospital with a 2-month history of fatigue and right-sided flank and abdominal pain. Noncontrast CT of the abdomen and pelvis revealed a 9.1 cm right renal mass.Contrast CT of the chest, abdomen and pelvis, MRI of the abdomen and pelvis with gadolinium, radionuclide bone scan, lung nodule biopsy, complete blood count, comprehensive metabolic profile, and measurement of serum lactate dehydrogenase.Stage IV, T3bN0M1 clear cell renal cell carcinoma, with an associated tumor thrombus extending into the vena cava.The patient was treated with neoadjuvant sunitinib, which resulted in a marked response in the primary tumor and metastatic lesions as well as regression of the tumor thrombus well into the renal vein. Thus, laparoscopic radical nephrectomy was feasible and was achieved without hemorrhagic or wound healing complications. One month after surgery, she had evidence of disease progression in the lung and a periaortic lymph node. She was restarted on sunitinib with resultant disease stabilization, but discontinued the drug owing to toxicity. Eight months after cessation of sunitinib, she received a dendritic cell vaccine. She remains alive without evidence of disease progression 2 years after her diagnosis.

  View details for DOI 10.1038/nrurol.2009.84

  View details for PubMedID 19498412

• A Controlled Vocabulary to Represent Sonographic Features of the Thyroid and its Application in a Bayesian Network to Predict Thyroid Nodule Malignancy 109th Annual Meeting of the American-Roentgen-Ray-Society Liu, Y., Kamaya, A., Desser, T., Rubin, D. AMER ROENTGEN RAY SOC. 2009

  View details for Web of Science ID 000265387200024

• Differentiating a Benign From Malignant Liver Lesion in the Pretransplant Cirrhotic Liver on Triphasic MDCT: When to Worry, When to Relax? 109th Annual Meeting of the American-Roentgen-Ray-Society Liu, Y., Shin, L., Kamaya, A., Jeffrey, R. AMER ROENTGEN RAY SOC. 2009

  View details for Web of Science ID 000265387200240

• Intraoperative Ultrasound of the Pancreas ULTRASOUND QUARTERLY Shin, L. K., Brant-Zawadzki, G., Kamaya, A., Jeffrey, R. B. 2009; 25 (1): 39-48

  Abstract

  Intraoperative ultrasound provides spatial resolution of the pancreas superior to computed tomography, magnetic resonance imaging, and transabdominal sonography. This pictorial essay will review common benign and malignant pancreatic processes including the following: pancreatic ductal adenocarcinoma, pancreatitis, endocrine tumors, mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, serous cystadenoma, and solid pseudopapillary tumor. The use of intraoperative ultrasound in specific surgical situations will be discussed, which include the following: (1) identification of insulinoma(s) which are not detectable preoperatively, (2) identification of the pancreatic duct to determine dissection planes for chronic pancreatitis surgery (eg, Puestow procedure) and for tumor resection, and (3) staging purposes for malignant disease.

  View details for Web of Science ID 000208118300005

  View details for PubMedID 19276960

• Optimal Vascular and Parenchymal Contrast Enhancement: The Current State of the Art RADIOLOGIC CLINICS OF NORTH AMERICA Fleischmann, D., Kamaya, A. 2009; 47 (1): 13-?

  Abstract

  A fundamental understanding of early arterial and parenchymal contrast medium (CM) dynamics is the basis for the design of CT scanning and injection protocols for state-of-the-art cardiovascular and body CT applications. Although normal parenchymal enhancement is primarily controlled by the total iodine dose injected per body weight, arterial enhancement is controlled by the iodine flux, the injection duration, and cardiac output. The technical capabilities of modern CT equipment allow and require precise scan timing to synchronize data acquisition with the desired phase of vascular enhancement (for CTA) and parenchymal enhancement (for liver and pancreatic CT). Automated tube current modulation and weight-based injection protocols allow individual optimization of radiation exposure and reduce interindividual variability of CM enhancement.

  View details for DOI 10.1016/j.rcl.2008.10.009

  View details for Web of Science ID 000263843900003

  View details for PubMedID 19195531

• A Controlled Vocabulary to Represent Sonographic Features of the Thyroid and its application in a Bayesian Network to Predict Thyroid Nodule Malignancy. Summit on translational bioinformatics Liu, Y. I., Kamaya, A., Desser, T. S., Rubin, D. L. 2009; 2009: 68-72

  Abstract

  It is challenging to distinguish benign from malignant thyroid nodules on high resolution ultrasound. Many ultrasound features have been studied individually as predictors for thyroid malignancy, none with a high degree of accuracy, and there is no consistent vocabulary used to describe the features. Our hypothesis is that a standard vocabulary will advance accuracy. We performed a systemic literature review and identified all the sonographic features that have been well studied in thyroid cancers. We built a controlled vocabulary for describing sonographic features and to enable us to unify data in the literature on the predictive power of each feature. We used this terminology to build a Bayesian network to predict thyroid malignancy. Our Bayesian network performed similar to or slightly better than experienced radiologists. Controlled terminology for describing thyroid radiology findings could be useful to characterize thyroid nodules and could enable decision support applications.

  View details for PubMedID 21347173

• Emergency Gynecologic Imaging SEMINARS IN ULTRASOUND CT AND MRI Kamaya, A., Shin, L., Chen, B., Desser, T. S. 2008; 29 (5): 353-368

  Abstract

  Acute pelvic pain in the female patient can have myriad presentations and, depending on the diagnosis, profound consequences. In the pregnant patient with pelvic pain or bleeding, an ectopic pregnancy must be first excluded. Ultrasound is important in determining the size and location of the ectopic pregnancy, and presence of bleeding, which in turn helps guide treatment decisions. Subchorionic or subplacental bleeds in an intrauterine pregnancy may also present with vaginal bleeding with consequences dependent on gestational age and size of bleed. In the postpartum female suspected to have retained products of conception, sonographic findings may vary from a thickened endometrial stripe to an echogenic mass with associated marked vascularity, often mimicking an arterial-venous malformation. In the nonpregnant patient, early diagnosis and treatment of ovarian torsion can preserve ovarian function. Other causes of peritoneal irritation may also cause acute pelvic pain including a ruptured hemorrhagic cyst or ruptured endometrioma. When pelvic inflammatory disease is suspected, imaging is used to evaluate for serious associated complications including the presence of a tuboovarian abscess or peritonitis. While leiomyomas of the uterus are largely asymptomatic, a leiomyoma that undergoes necrosis, torsion or prolapse through the cervix may be associated with acute severe pain or bleeding. The imaging features of these and other important clinical entities in the female pelvis will be presented.

  View details for DOI 10.1053/j.sult.2008.06.006

  View details for PubMedID 18853841

• Fetus in fetu: 11 fetoid forms in a single fetus - Review of the literature and imaging JOURNAL OF ULTRASOUND IN MEDICINE Gerber, R. E., Kamaya, A., Miller, S. S., Cronin, D. M., Dwyer, B., Chueh, J., Conner, K. E., Barth, R. A. 2008; 27 (9): 1381-1387

  View details for Web of Science ID 000258853200015

  View details for PubMedID 18716149

• Ultrasound of thyroid nodules NEUROIMAGING CLINICS OF NORTH AMERICA Desser, T. S., Kamaya, A. 2008; 18 (3): 463-478

  Abstract

  Thyroid nodules can be detected in 4% to 8% of the adult population by palpation, but in 40% to 50% of the population by ultrasound. The overwhelming majority of these represent benign hyperplastic nodules or adenomas. Approximately 5% of nodules are malignant, with papillary carcinoma representing approximately 75% to 80% of primary thyroid malignancies. Although many sonographic features have been studied as a means of distinguishing benign from malignant nodules, ultrasound-guided fine-needle aspiration with cytologic evaluation remains a mainstay in the management of palpable and incidentally detected nodules. This article reviews the current techniques for sonographic evaluation of the thyroid and the imaging features of the various types of thyroid nodules.

  View details for DOI 10.1016/j.nic.2008.03.005

  View details for PubMedID 18656028

• An unusual imaging and clinical presentation of papillary thyroid carcinoma JOURNAL OF ULTRASOUND IN MEDICINE Liu, Y. I., Shin, L. K., Kamaya, A., Jeffrey, R. B. 2008; 27 (8): 1241-1244

  View details for PubMedID 18645084

• Initial evaluation of F-18-fluorothymidine (FLT) PET/CT scanning for primary pancreatic cancer EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING Quon, A., Chang, S. T., Chin, F., Kamaya, A., Dick, D. W., Loo, B. W., Gambhir, S. S., Koong, A. C. 2008; 35 (3): 527-531

  Abstract

  The aim of this study was to evaluate the potential of (18)F-fluorothymidine (FLT) PET/CT for imaging pancreatic adenocarcinoma.This was a pilot study of five patients (four males, one female) with newly diagnosed and previously untreated pancreatic adenocarcinoma. Patients underwent FLT PET/CT, (18)F-fluorodeoxyglucose (FDG) PET/CT, and contrast-enhanced CT scanning before treatment. The presence of cancer was confirmed by histopathological analysis at the time of scanning in all five patients. The degree of FLT and FDG uptake at the primary tumor site was assessed using visual interpretation and semi-quantitative SUV analyses.The primary tumor size ranged from 2.5 x 2.8 cm to 3.5 x 7.0 cm. The SUV of FLT uptake within the primary tumor ranged from 2.1 to 3.1. Using visual interpretation, the primary cancer could be detected from background activity in two of five patients (40%) on FLT PET/CT. By comparison, FDG uptake was higher in each patient with a SUV range of 3.4 to 10.8, and the primary cancer could be detected from background in all five patients (100%).In this pilot study of five patients with primary pancreatic adenocarcinoma, FLT PET/CT scanning showed poor lesion detectability and relatively low levels of radiotracer uptake in the primary tumor.

  View details for DOI 10.1007/s00259-007-0630-z

  View details for Web of Science ID 000254402800010

  View details for PubMedID 17960376

• A Bayesian classifier for differentiating benign versus malignant thyroid nodules using sonographic features. AMIA ... Annual Symposium proceedings / AMIA Symposium. AMIA Symposium Liu, Y. I., Kamaya, A., Desser, T. S., Rubin, D. L. 2008: 419-423

  Abstract

  Thyroid nodules are a common, yet challenging clinical problem. The vast majority of these nodules are benign; however, deciding which nodule should undergo biopsy is difficult because the imaging appearance of benign and malignant thyroid nodules overlap. High resolution ultrasound is the primary imaging modality for evaluating thyroid nodules. Many sonographic features have been studied individually as predictors for thyroid malignancy. There has been little work to create predictive models that combine multiple predictors, both imaging features and demographic factors. We have created a Bayesian classifier to predict whether a thyroid nodule is benign or malignant using sonographic and demographic findings. Our classifier performed similar to or slightly better than experienced radiologists when evaluated using 41 thyroid nodules with known pathologic diagnosis. This classifier could be helpful in providing practitioners an objective basis for deciding whether to biopsy suspicious thyroid nodules.

  View details for PubMedID 18999209

• Investigating Large 2D Arrays for Photoacoustic and Acoustic Imaging using CMUT Technology IEEE Ultrasonics Symposium Vaithilingam, S., Ma, T., Furukawa, Y., Oralkan, O., Kamaya, A., Torashima, K., Kupnik, M., Wygant, I. O., Zhuang, X., Jeffrey, R. B., Khuri-Yakub, B. T. IEEE. 2008: 1238–1241

  View details for Web of Science ID 000268845800299

• A co-axial scanning acoustic and. photoacoustic microscope IEEE Ultrasonics Symposium Vaithilingam, S., Ma, T., Furukawa, Y., de la Zerda, A., Oralkan, O., Kamaya, A., Keren, S., Gambhir, S. S., Jeffrey, R. B., Khuri-Yakub, B. T. IEEE. 2007: 2413–2416

  View details for Web of Science ID 000254281802104

• Sonography of the abnormal parathyroid gland. Ultrasound quarterly Kamaya, A., Quon, A., Jeffrey, R. B. 2006; 22 (4): 253-262

  Abstract

  In 80% to 90% of patients with primary hyperparathyroidism, a single parathyroid adenoma will be identified as the culprit, whereas the remaining 10% to 20% are caused by multiple adenomas, parathyroid hyperplasia, and rarely, parathyroid carcinoma. At the 2002 National Institute of Health consensus meeting, minimally invasive parathyroidectomy was endorsed as a promising and attractive alternative to total parathyroidectomy. Therefore, preoperative localization of the adenoma is critical in the clinical evaluation of the patient before surgical resection. Although adenomas less than 1 cm may be difficult to visualize sonographically, knowledge of typical imaging characteristics of parathyroid adenomas and use of special sonographic techniques will facilitate identification in most patients. Typical imaging characteristics of parathyroid adenomas include homogeneously hypoechoic echotexture on gray scale with an enlarged feeding artery and peripheral arc of vascularity seen on color and power Doppler. Proper neck extension, unilateral graded compression techniques, and patient swallowing will improve visualization of adenomas.

  View details for PubMedID 17146333

• Multiple lesions of the spleen: Differential diagnosis of cystic and solid lesions SEMINARS IN ULTRASOUND CT AND MRI Kamaya, A., Weinstein, S., Desser, T. S. 2006; 27 (5): 389-403

  Abstract

  Lesions in the spleen may be encountered in a variety of clinical settings ranging from asymptomatic patients to patients who are critically ill. Etiologies for multifocal splenic lesions include infectious and inflammatory processes, primary vascular and lymphoid neoplasms, metastatic disease, vascular processes, and systemic diseases. There is often overlap in the imaging appearance alone, so the clinical setting is very helpful in differential diagnosis. In the immunocompromised patient, multiple small splenic lesions usually represent disseminated fungal disease and microabscesses. The spleen is a relatively rare site for metastatic disease; patients with metastatic lesions in the spleen usually have disease in other sites as well. Breast, lung, ovary, melanoma, and colon cancer are common primary tumors that metastasize to the spleen. Vascular neoplasms of the spleen represent the majority of the nonhematologic/nonlymphoid neoplasms and commonly produce multifocal lesions. Splenic infarcts may be seen with localized processes such as portal hypertension or pancreatitis, or may arise from an embolic source. Radiologists should be aware of the spectrum of processes that may involve the spleen and the clinical context in which they occur.

  View details for DOI 10.1053/j.sult.2006.06.004

  View details for PubMedID 17048454

• Multidetector CT imaging thoracoabdominal of aortic aneurysms 105th Annual Meeting of the American-Roentgen-Ray-Society Kamaya, A., Cheung, S., Miller, D. C., Hellinger, J. C., Hallett, R., Fleischmann, D. AMER ROENTGEN RAY SOC. 2005: 134–34

  View details for Web of Science ID 000228717800566

• Characterization of a linear streak artifact with pulse inversion tissue harmonics in musculoskeletal Sonography 13th Annual Meeting of the Society-of-Radiologists-in-Ultrasound Kamaya, A., Abate, S., Nan, B., Grover, I., Adler, R. S., Jamadar, D., Rubin, J. M. AMER INST ULTRASOUND MEDICINE. 2004: 1597–1605

  Abstract

  To understand a linear artifact that projects deep to reflective structures that move rapidly while using tissue harmonic imaging with pulse inversion (PI) sonography. We hypothesize that this artifact is due to a cancellation error between firings in PI imaging, and it is, therefore, similar in generation to the twinkling artifact in color Doppler sonography. This artifact could be studied with the use of surfaces of different roughness to represent different rates of motion, in which roughness corresponds to spatial fluctuations in surface height. Given very slight variations in beam focusing as occurs with sonographic imaging arrays, these spatial fluctuations translate into temporal fluctuations in the received signal as would occur with tissue motion.We scanned 4 different sandpaper grits and a smooth surface through a water path using fundamental and PI mode, 1- and 2-pulse techniques, respectively. The sandpaper and the smooth surface were scanned through a water path at mechanical indices of 0.1 to 0.7. Four independent images were subtracted pairwise to remove nonfluctuating signals. These noise pixels were counted and analyzed.Analysis of variance showed that the noise generated behind the different surfaces was highly significantly different. Two-tailed t tests generally showed significant differences in the quantity of noise between fundamental and harmonic imaging behind the roughest 3 grades of sandpaper. A multiple regression model showed significantly greater slopes for harmonic imaging for all grades of sandpaper and the smooth surface.The noise and, by extension, the linear streak artifact in musculoskeletal imaging are dependent on the mechanical index and are functions of sandpaper roughness. This would be equivalent to a subtraction error between 2 firings due to soft tissue motion, and the artifact may be a way to identify rapid soft tissue motion in PI images.

  View details for Web of Science ID 000225515300006

  View details for PubMedID 15557302

• Twinkling artifact on color Doppler sonography: Dependence on machine parameters and underlying cause 102nd Annual Meeting of the American-Roentgen-Ray-Society Kamaya, A., Tuthill, T., Rubin, J. M. AMER ROENTGEN RAY SOC. 2003: 215–22

  Abstract

  The objective of our study was to evaluate the color Doppler sonographic effect known as twinkling artifact.Struvite (ammonium magnesium phosphate) stone fragments, wire mesh, and a flat surface were scanned in a water bath with a sonography scanner using a high-frequency linear array probe fixed in a ring clamp. Pulse repetition frequency, color-write priority, gray-scale gain, and spectral Doppler gain were varied. Color and spectral Doppler modes were used.Twinkling artifact and spectral broadening were seen most intensely behind struvite stone fragments, and both were seen more strongly behind wire mesh with greater surface roughness than behind wire mesh with less surface roughness or a flat surface. The appearance of the twinkling artifact is highly dependent on machine settings. System noise measured on a flat surface generates a band-limited Doppler shift on spectral displays with a mean frequency shift of 0 Hz and a mean (+/- SD) absolute fluctuation of 86 +/- 10 Hz over a pulse repetition frequency range of 1250-10,000 Hz. Rough surfaces increase the spectral bandwidth.The appearance of the twinkling artifact is highly dependent on machine settings and is likely generated by a narrow-band, intrinsic machine noise called phase (or clock) jitter. Surface roughness secondarily broadens the noise spectrum. With a strongly reflecting, rough surface such as a renal stone, the high amplitude, broadband signal appears as random motion in color Doppler sonography. Understanding of the twinkling artifact may result in better use of its clinical appearance.

  View details for Web of Science ID 000179979400040

  View details for PubMedID 12490508

• 2017 Version of LI-RADS for CT and MR Imaging: An Update. Radiographics : a review publication of the Radiological Society of North America, Inc Elsayes, K. M., Hooker, J. C., Agrons, M. M., Kielar, A. Z., Tang, A. n., Fowler, K. J., Chernyak, V. n., Bashir, M. R., Kono, Y. n., Do, R. K., Mitchell, D. G., Kamaya, A. n., Hecht, E. M., Sirlin, C. B. ; 37 (7): 1994–2017

  Abstract

  The Liver Imaging Reporting and Data System (LI-RADS) is a reporting system created for the standardized interpretation of liver imaging findings in patients who are at risk for hepatocellular carcinoma (HCC). This system was developed with the cooperative and ongoing efforts of an American College of Radiology-supported committee of diagnostic radiologists with expertise in liver imaging and valuable input from hepatobiliary surgeons, hepatologists, hepatopathologists, and interventional radiologists. In this article, the 2017 version of LI-RADS for computed tomography and magnetic resonance imaging is reviewed. Specific topics include the appropriate population for application of LI-RADS; technical recommendations for image optimization, including definitions of dynamic enhancement phases; diagnostic and treatment response categories; definitions of major and ancillary imaging features; criteria for distinguishing definite HCC from a malignancy that might be non-HCC; management options following LI-RADS categorization; and reporting. (©)RSNA, 2017.

  View details for PubMedID 29131761