Stanford University, BS 2010
Brown University, MD 2015
Scripps Transitional Year, Intern
University of California San Diego, Residency

Clinical Focus

  • Body Imaging

Academic Appointments

  • Clinical Assistant Professor, Radiology

Professional Education

  • Residency: UCSD Dept of Radiology (2020) CA
  • Internship: Scripps Mercy Hospital San Diego (2016) CA
  • Board Certification: American Board of Radiology, Diagnostic Radiology (2021)
  • Fellowship: Stanford University Body Imaging Fellowship (2021) CA
  • Medical Education: Brown University School of Medicine (2015) RI

2023-24 Courses

All Publications

  • 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


    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

  • Portal Venous Aneurysm. Radiology Murty, T., Negrete, L. 2023: 221311


    Supplemental material is available for this article.

    View details for DOI 10.1148/radiol.221311

    View details for PubMedID 36749214

  • Bunch of grapes - I saw the sign. Clinical imaging Hwang, J., Negrete, L. 2023; 96: 23-25


    As early as the late 1800s, the appearance of hydatidiform moles have been likened to grapes. The bunch of grapes sign is an ultrasound finding of a heterogenous mass within the uterine cavity with multiple anechoic spaces. We saw the bunch of grapes sign on a 28-year-old on ultrasound.

    View details for DOI 10.1016/j.clinimag.2023.01.010

    View details for PubMedID 36738666

  • 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


    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

  • I saw the "bear paw" sign - Massive renal xanthogranulomatous pyelonephritis. Clinical imaging Mynarski, N. J., Shen, L., Negrete, L. M. 2022; 93: 70-74


    The bear paw sign is a radiologic sign seen on computed tomography (CT) that indicates the development of xanthogranulomatous pyelonephritis (XGP). It refers to the multiple, rim-enhancing, low attenuation renal collections seen in the diffuse form of XGP. The term "bear paw" sign first appeared in the literature in 1989 and has since been widely used to describe this serious, but treatable, pathology.

    View details for DOI 10.1016/j.clinimag.2022.11.006

    View details for PubMedID 36410078

  • Duodenal Brunner Gland Hamartoma. Radiology Negrete, L. M., Chughtai, K. 2022: 220539


    Online supplemental material is available for this article.

    View details for DOI 10.1148/radiol.220539

    View details for PubMedID 36125378

  • 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


    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

  • 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


    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

  • Jumping to conclusions: Misdiagnosing radiation induced sarcoma as recurrent breast cancer. Clinical imaging Chughtai, K., Negrete, L., Vitzthum, L. K. 2022; 84: 110-112


    Radiation therapy (RT) induced chondrosarcoma is a rare but important potential complication seen in cancer patients treated with radiation. Although uncommon, these patients tend to have a poor prognosis, so early detection and complete resection are the crucial steps towards survival. We present the case of an 81-year-old breast cancer patient who was treated with RT to the left chest wall. Eight years later, she presented with a growing left chest wall mass, initially thought to represent local breast cancer recurrence. Imaging demonstrated a well-defined mass arising from the left pectoralis major muscle. The mass was excised, and pathology demonstrated chondrosarcoma. We discuss the clinical and radiologic aspects of RT-induced sarcomas with attention to the very rare chondrosarcoma. The aim of this report is to provide a succinct but relevant summary of the diagnostic considerations for RT-induced sarcoma supported by information about epidemiology, clinical diagnostic criteria, and radiation biology to expedite patient workup and ultimately improve patient outcomes.

    View details for DOI 10.1016/j.clinimag.2022.01.014

    View details for PubMedID 35176572

  • Progression Versus Radiation Treatment Changes After Stereotactic Ablative Radiation Therapy of a Liver Metastasis PRACTICAL RADIATION ONCOLOGY No, H. J., Negrete, L. M., Pollom, E. L., Wakelee, H. A., Chang, D. T., Vitzthum, L. K. 2022; 12 (1): 1-2
  • Inflammatory pseudotumor-like follicular dendritic cell tumor of the spleen: a case report and approach to differential diagnosis. Radiology case reports Nguyen, A., Negrete, L. M., Bulterys, P. L., Shen, L. 2021; 16 (11): 3213-3216


    We present a case of an inflammatory pseudotumor-like follicular dendritic cell tumor of the spleen. The patient is a 44-year-old woman, without significant underlying history, who presented with nonspecific abdominal pain for a few months. Both a contrast enhanced computed tomography and magnetic resonance imaging revealed a new 2.5 cm enhancing splenic lesion, which demonstrated hypermetabolic activity on subsequent positron emission tomography and computed tomography scan. Since the lesion was new compared to more remote imaging and hypermetabolic, a splenectomy was performed. Pathology confirmed the diagnosis and demonstrated positivity for Epstein-Barr Virus .

    View details for DOI 10.1016/j.radcr.2021.07.078

    View details for PubMedID 34484521