Nathan E. Frenk
Harvard University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Nathan E. Frenk.
American Journal of Roentgenology | 2014
Nathan E. Frenk; Ronaldo Hueb Baroni; Francisco Cesar Carnevale; Octavio Meneghelli Gonçalves; Alberto A. Antunes; Miguel Srougi; Giovanni Guido Cerri
OBJECTIVE The purpose of this article is to assess and describe the MRI findings after prostatic artery embolization for treatment of benign prostatic hyperplasia. MATERIALS AND METHODS We retrospectively evaluated 17 patients who underwent prostatic artery embolization as part of different prospective studies to evaluate this alternative treatment of benign prostatic hyperplasia. Clinical results were evaluated by assessment of urinary catheterization and International Prostate Symptom Score (IPSS). Serial MRI examinations were performed, and the prostatic central gland and peripheral zone were evaluated for signal intensity changes and the presence and characteristics of infarcted areas. Statistical analysis was performed with ANOVA for repeated measures and Student t test. RESULTS All patients had clinical success, as defined by the removal of indwelling urinary catheter or decreased IPSS after embolization. Infarcts were seen in 70.6% of the subjects, exclusively in the central gland, were almost always characterized by hyperintensity on T1-weighted images and predominant hypointensity on T2-weighted images, and became smaller (mean reduction, p < 0.001) and isointense to the remaining of the central gland over time. Volume reduction of the prostate after embolization was significant (averaging 32.0% after 12-18 months; p < 0.001) only in patients with infarcts. No statistically significant association was seen between the development of infarcts and IPSS. CONCLUSION MRI can be used for assessing the development of infarcts and volume reduction in the prostate after embolization. Further studies are needed to correlate these findings to clinical outcome.
JCO Precision Oncology | 2017
Nathan E. Frenk; Laura Spring; Alona Muzikansky; Harshna Vadvala; Joseph M. Gurski; Laura Henderson; Mari Mino-Kenudson; Amy Ly; Aditya Bardia; Dianne M. Finkelstein; Jeffrey A. Engelman; Peter R. Mueller; Dejan Juric; Ralph Weissleder
PurposePrecision oncology relies on frequent pathologic, molecular, and genomic assessments of tumor tissue to guide treatment selection, evaluate pharmacodynamic effects of novel agents, and determine drug resistance mechanisms. Newer forms of analyses such as drug screens in cell lines and patient-derived xenografts demand increasing amounts of tissue material. It remains unknown how the need for serial biopsies with large numbers of tumor cores relates to tissue yields and biopsy complication rates.Materials and MethodsIn this study, we performed a retrospective analysis of 199 focal liver biopsies performed in 143 patients in the setting of oncologic research protocols (research biopsy group) over a 4-year period at a single-intervention oncology service. Practice patterns and complication rates were compared with those related to 1,522 consecutive biopsies performed in 1,154 patients in whom two cores were obtained for standard clinical management of patients (standard biopsy).ResultsIn the research ...
Clinics | 2016
Nathan E. Frenk; Fernando Moreno Sebastianes; Antonio M. Lerario; Maria Candida Barisson Villares Fragoso; Berenice B. Mendonca; Marcos Roberto de Menezes
OBJECTIVES: To evaluate the safety and long-term efficacy of computed tomography-guided percutaneous ethanol ablation for benign primary and secondary hyperfunctioning adrenal disorders. METHOD: We retrospectively evaluated the long-term results of nine patients treated with computed tomography-guided percutaneous ethanol ablation: eight subjects who presented with primary adrenal disorders, such as pheochromocytoma, primary macronodular adrenal hyperplasia and aldosterone-producing adenoma, and one subject with Cushing disease refractory to conventional treatment. Eleven sessions were performed for the nine patients. The patient data were reviewed for the clinical outcome and procedure-related complications over ten years. RESULTS: Patients with aldosterone-producing adenoma had clinical improvement: symptoms recurred in one case 96 months after ethanol ablation, and the other patient was still in remission 110 months later. All patients with pheochromocytoma had clinical improvement but were eventually submitted to surgery for complete remission. No significant clinical improvement was seen in patients with hypercortisolism due to primary macronodular adrenal hyperplasia or Cushing disease. Major complications were seen in five of the eleven procedures and included cardiovascular instability and myocardial infarction. Minor complications attributed to sedation were seen in two patients. CONCLUSION: Computed tomography-guided ethanol ablation does not appear to be suitable for the long-term treatment of hyperfunctioning adrenal disorders and is not without risks.
Journal of Radiology Case Reports | 2017
Lucas Fiore; Nathan E. Frenk; Guilherme Lopes Pinheiro Martins; Publio Cesar Cavalcante Viana; Marcos Roberto de Menezes
CT-guided percutaneous biopsy is a resourceful and widely used tool to evaluate pulmonary nodules that frequently avoids costly and unnecessary surgeries. Severe complications occur in less than 1% of cases and include gas embolism, which is rarely documented. We report a case of gas embolism after transthoracic biopsies and discuss the pathophysiology and the benefits of early diagnosis and proper management.
Journal of Vascular and Interventional Radiology | 2017
Harshna Vadvala; Vanessa Fiorini Furtado; Avinash Kambadakone; Nathan E. Frenk; Peter R. Mueller; Ronald S. Arellano
Journal of Vascular and Interventional Radiology | 2017
Nathan E. Frenk; Dania Daye; Kemal Tuncali; Ronald S. Arellano; Paul B. Shyn; Stuart G. Silverman; Florian J. Fintelmann; Raul N. Uppot
Journal of Vascular and Interventional Radiology | 2016
Nathan E. Frenk; Tiffany E. Chao; Jie Cui; Peter J. Fagenholz; Z. Irani
Journal of Vascular and Interventional Radiology | 2016
Aoife Kilcoyne; Nathan E. Frenk; Ronald S. Arellano
Pediatria (Säo Paulo) | 2009
Nathan E. Frenk; Chong Ae Kim; Magda Carneiro-Sampaio; Noemia Mie Orii; Dewton de Moraes Vasconcelos
Journal of Vascular and Interventional Radiology | 2018
Dania Daye; A. Tabari; M. Caton; Nathan E. Frenk; Florian J. Fintelmann; Michael S. Gee; Raul N. Uppot