Kristen Bird

All Publications

• 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

• 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

• Automated Identification and Measurement Extraction of Pancreatic Cystic Lesions from Free-Text Radiology Reports Using Natural Language Processing. Radiology. Artificial intelligence Yamashita, R., Bird, K., Cheung, P. Y., Decker, J. H., Flory, M. N., Goff, D., Morimoto, L. N., Shon, A., Wentland, A. L., Rubin, D. L., Desser, T. S. 2022; 4 (2): e210092

  Abstract

  Purpose: To automatically identify a cohort of patients with pancreatic cystic lesions (PCLs) and extract PCL measurements from historical CT and MRI reports using natural language processing (NLP) and a question answering system.Materials and Methods: Institutional review board approval was obtained for this retrospective Health Insurance Portability and Accountability Act-compliant study, and the requirement to obtain informed consent was waived. A cohort of free-text CT and MRI reports generated between January 1991 and July 2019 that covered the pancreatic region were identified. A PCL identification model was developed by modifying a rule-based information extraction model; measurement extraction was performed using a state-of-the-art question answering system. The system's performance was evaluated against radiologists' annotations.Results: For this study, 430426 free-text radiology reports from 199783 unique patients were identified. The NLP model for identifying PCL was applied to 1000 test samples. The interobserver agreement between the model and two radiologists was almost perfect (Fleiss kappa = 0.951), and the false-positive rate and true-positive rate were 3.0% and 98.2%, respectively, against consensus of radiologists' annotations as ground truths. The overall accuracy and Lin concordance correlation coefficient for measurement extraction were 0.958 and 0.874, respectively, against radiologists' annotations as ground truths.Conclusion: An NLP-based system was developed that identifies patients with PCLs and extracts measurements from a large single-institution archive of free-text radiology reports. This approach may prove valuable to study the natural history and potential risks of PCLs and can be applied to many other use cases.Keywords: Informatics, Abdomen/GI, Pancreas, Cysts, Computer Applications-General (Informatics), Named Entity Recognition Supplemental material is available for this article. © RSNA, 2022See also commentary by Horii in this issue.

  View details for DOI 10.1148/ryai.210092

  View details for PubMedID 35391762

• 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

• 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

• 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