- Diagnostic Radiology
Clinical Assistant Professor, Radiology
Fellowship: UCSF Dept of Radiology (2010) CA
Fellowship: Stanford University Radiology Fellowships (2011) CA
Residency: New York Presbyterian Cornell Campus Radiology Training (2009) NY
Internship: University of Hawaii Internal Medicine Residency Program (2005) HI
Board Certification: American Board of Radiology, Interventional Radiology and Diagnostic Radiology (2017)
Medical Education: Weill Cornell Medical College (2004) NY
Applying a Structured Innovation Process to Interventional Radiology: A Single-Center Experience
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2012; 23 (4): 488-494
To determine the feasibility and efficacy of applying an established innovation process to an active academic interventional radiology (IR) practice.The Stanford Biodesign Medical Technology Innovation Process was used as the innovation template. Over a 4-month period, seven IR faculty and four IR fellow physicians recorded observations. These observations were converted into need statements. One particular need relating to gastrostomy tubes was diligently screened and was the subject of a single formal brainstorming session.Investigators collected 82 observations, 34 by faculty and 48 by fellows. The categories that generated the most observations were enteral feeding (n = 9, 11%), biopsy (n = 8, 10%), chest tubes (n = 6, 7%), chemoembolization and radioembolization (n = 6, 7%), and biliary interventions (n = 5, 6%). The output from the screening on the gastrostomy tube need was a specification sheet that served as a guidance document for the subsequent brainstorming session. The brainstorming session produced 10 concepts under three separate categories.This formalized innovation process generated numerous observations and ultimately 10 concepts to potentially to solve a significant clinical need, suggesting that a structured process can help guide an IR practice interested in medical innovation.
View details for DOI 10.1016/j.jvir.2011.12.029
View details for Web of Science ID 000302396300009
View details for PubMedID 22464713
Intravascular Ultrasound-Guided Mesocaval Shunt Creation in Patients with Portal or Mesenteric Venous Occlusion
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2012; 23 (1): 136-141
Extrahepatic mesocaval shunts were successfully created in three patients with refractory variceal hemorrhage, complete portal vein or superior mesenteric vein occlusion, and contraindications to shunt surgery. The use of intravascular ultrasound guidance and covered stents allowed safe and effective transvenous shunt creation without the necessity of percutaneous transabdominal mesenteric venous puncture.
View details for DOI 10.1016/j.jvir.2011.09.029
View details for PubMedID 22221479
Morbidity of Direct MR Arthrography
AMERICAN JOURNAL OF ROENTGENOLOGY
2011; 196 (4): 868–74
The purpose of this study was to determine the incidence and severity of arthrographic pain after intraarticular injection of a gadolinium mixture diluted in normal saline for direct MR arthrography.From March 2009 until January 2010, 155 consecutive patients underwent direct MR arthrography; 20 patients were lost to follow-up. Patients were contacted by telephone between 3 and 7 days after joint injection. Using an 11-point numeric pain rating scale, patients were asked to report if they had experienced joint pain that was different or more intense than their preinjection baseline, the severity of pain, the duration of pain, time to onset of pain, and eventual resolution of pain.The incidence of postarthrographic pain was 66% (89/135), with an average intensity of pain of 4.8 ± 2.4 (range, 1-10). Postarthrographic pain lasted an average of 44.4 ± 30.5 hours (range, 6-168 hours). The time to onset of pain after joint injection was on average 16.6 ± 13.1 hours (range, 4-72 hours). There was no significant difference regarding the severity or incidence of postarthrographic pain between groups on the basis of patient age (p = 0.20 and 0.26), patient sex (p = 0.20 and 0.86), contrast mixture contents (p = 0.83 and 0.49), or joint injected (p = 0.51 and 0.47). No patients experienced any other serious side effects.Sixty-six percent of patients who undergo direct MR arthrography will experience a fairly severe delayed onset of pain that completely resolves over the course of several days.
View details for DOI 10.2214/AJR.10.5145
View details for Web of Science ID 000288650600045
View details for PubMedID 21427338
Limitations of CT during PET/CT
JOURNAL OF NUCLEAR MEDICINE
2007; 48 (10): 1583–91
Our aim was to determine the diagnostic limitations of low-dose, unenhanced CT scans performed for anatomic reference and attenuation correction during PET/CT.The Radiology Information System at our oncologic hospital was queried during the 9-mo period from July 2002 to April 2003 for patients with PET/CT scans and diagnostic enhanced CT within 2 wk of each other. One radiologist interpreted the CT portion of the PET/CT (CT(p)) unaware of the PET results and the associated enhanced diagnostic CT (CT(d)). A medical student compared this interpretation with the official report of the CT(d) and listed all discrepancies between reports. A separate radiologist compared CT(p) and CT(d) images and classified true discrepant findings as due to lack of intravenous contrast, arm-position artifact, lack of enteric contrast, low milliamperage (mA), and quality of lung images.Among 100 patients, the most common malignancies were lymphoma (n = 37), cancer of the colorectum (n = 31), and esophageal cancer (n = 15). Among 194 true discrepancies in which findings were missed at CT(p), causes were as follows: (a) lack of intravenous contrast (128/194, 66%), (b) arm-down artifact (17/194, 9%), (c) quality of lung images (26/194, 13%), (d) lack of enteric contrast (15/194, 8%), and (e) low mA (8/194, 4%). Discrepancies were seen most commonly in detecting lymphadenopathy and visceral metastases.Most missed findings on the unenhanced CT portion of the PET/CT scans were due to technical factors that could be altered. Discrepant findings would have led to altered management in only 2 patients, suggesting a role for limited repeat imaging to reduce radiation and use of valuable resources.
View details for DOI 10.2967/jnumed.107.043109
View details for Web of Science ID 000252894800026
View details for PubMedID 17873133
Interaction of hormone-sensitive lipase with steroidogeneic acute regulatory protein - Facilitation of cholesterol transfer in adrenal
JOURNAL OF BIOLOGICAL CHEMISTRY
2003; 278 (44): 43870-43876
Hormone-sensitive lipase (HSL) is responsible for the neutral cholesteryl ester hydrolase activity in steroidogenic tissues. Through its action, HSL is involved in regulating intracellular cholesterol metabolism and making unesterified cholesterol available for steroid hormone production. Steroidogenic acute regulatory protein (StAR) facilitates the movement of cholesterol from the outer mitochondrial membrane to the inner mitochondrial membrane and is a critical regulatory step in steroidogenesis. In the current studies we demonstrate a direct interaction of HSL with StAR using in vitro glutathione S-transferase pull-down experiments. The 37-kDa StAR is coimmunoprecipitated with HSL from adrenals of animals treated with ACTH. Deletional mutations show that HSL interacts with the N-terminal as well as a central region of StAR. Coexpression of HSL and StAR in Chinese hamster ovary cells results in higher cholesteryl ester hydrolytic activity of HSL. Transient overexpression of HSL in Y1 adrenocortical cells increases mitochondrial cholesterol content under conditions in which StAR is induced. It is proposed that the interaction of HSL with StAR in cytosol increases the hydrolytic activity of HSL and that together HSL and StAR facilitate cholesterol movement from lipid droplets to mitochondria for steroidogenesis.
View details for DOI 10.1074/jbc.M303934200
View details for Web of Science ID 000186157000137
View details for PubMedID 12925534
Intercalary tibial allografts following tumor resection: The role of fibular centralization
2003; 26 (6): 631-637
Options to reconstruct intercalary tibial defects include allografts, vascularized bone transfers, autogenous cortical grafts, endoprostheses, and Ilizarov bone transport. Five patients underwent intercalary bulk allograft reconstruction following en bloc resection of tibial sarcomas. Two patients underwent immediate fibular centralization and iliac crest bone grafting in addition to the allograft. Two patients who underwent fibular centralization during primary reconstruction united uneventfully. The remaining three patients developed nonunion, of which one was successfully salvaged by fibular centralization. A combined allograft transplant and fibular centralization with iliac crest bone grafting is an effective procedure to reconstruct the tibial diaphysis, as well as a salvage procedure for allograft nonunion.
View details for PubMedID 12817729
Characterization of the functional interaction of adipocyte lipid-binding protein with hormone-sensitive lipase
JOURNAL OF BIOLOGICAL CHEMISTRY
2001; 276 (52): 49443-49448
Hormone-sensitive lipase (HSL) is an intracellular lipase that plays an important role in the hydrolysis of triacylglycerol in adipose tissue. HSL has been shown to interact with adipocyte lipid-binding protein (ALBP), a member of the family of intracellular lipid-binding proteins that bind fatty acids and other hydrophobic ligands. The current studies have addressed the functional significance of the association and mapped the site of interaction between HSL and ALBP. Incubation of homogeneous ALBP with purified, recombinant HSL in vitro resulted in a 2-fold increase in substrate hydrolysis. Moreover, the ability of oleate to inhibit HSL hydrolytic activity was attenuated by co-incubation with ALBP. Co-transfection of Chinese hamster ovary cells with HSL and ALBP resulted in greater hydrolytic activity than transfection of cells with HSL and vector alone. Deletional mutations of HSL localized the region of HSL that interacts with ALBP to amino acids 192-200, and site-directed mutagenesis of individual amino acids in this region identified His-194 and Glu-199 as critical for mediating the interaction of HSL with ALBP. Interestingly, HSL mutants H194L and E199A, each of which retained normal basal hydrolytic activity, failed to display an increase in hydrolytic activity when co-transfected with wild type ALBP. Therefore, ALBP increases the hydrolytic activity of HSL through its ability to bind and sequester fatty acids and via specific protein-protein interaction. Thus, HSL and ALBP constitute a functionally important lipolytic complex.
View details for DOI 10.1074/jbc.M104095200
View details for Web of Science ID 000173922100106
View details for PubMedID 11682468
Hormone-sensitive lipase functions as an oligomer
2000; 39 (9): 2392-2398
Hormone-sensitive lipase (HSL) is a cytosolic neutral lipase whose activity is regulated by reversible phosphorylation and which is thought to be the rate-limiting enzyme for the mobilization of FFA from adipose tissue. In the current studies the subunit structure of HSL has been explored using sucrose gradient centrifugation and in vivo and in vitro protein-protein interactions. Evidence is provided to demonstrate that HSL exists as a functional dimer composed of homologous subunits. Dimeric HSL displayed approximately 40-fold greater activity against cholesteryl ester substrate when compared with monomeric HSL without any differences in affinity for the substrate. Truncations of HSL identified the importance of the N-terminal 300 amino acids, as well as other regions, in participating in the oligomerization of HSL. These studies support the notion that the N-terminal region of HSL represents a docking domain for protein-protein interactions and provide an additional mechanism for the posttranslational control of HSL activity in the cell via oligomerization.
View details for Web of Science ID 000085769700031
View details for PubMedID 10694408