Bio

Clinical Focus


  • Neuroradiology
  • Diagnostic Radiology

Academic Appointments


Professional Education


  • Fellowship:Stanford University School of Medicine (2013) CA
  • Board Certification, Neuroradiology, American Board of Radiology (2013)
  • Board Certification: Diagnostic Radiology, American Board of Radiology (2011)
  • Residency:Santa Clara Valley Medical Center (2011) CA
  • Internship:Cedars Sinai Medical Center (2007) CA
  • Medical Education:David Geffen School of Medicine at UCLA (2006) CA

Publications

Journal Articles


  • Prolonged Survival of Patients With Non-Small-Cell Lung Cancer With Leptomeningeal Carcinomatosis in the Modern Treatment Era. Clinical lung cancer Riess, J. W., Nagpal, S., Iv, M., Zeineh, M., Gubens, M. A., Ramchandran, K., Neal, J. W., Wakelee, H. A. 2014

    Abstract

    Leptomeningeal carcinomatosis (LM) is a severe complication of non-small-cell lung cancer (NSCLC) historically associated with poor prognosis. New chemotherapeutic and targeted treatments could potentially affect the natural history of LM.Patients with a pathologic diagnosis of NSCLC with LM treated at Stanford between 2003 and 2011 were identified via institutional databases and medical records. LM was defined by cerebrospinal fluid (CSF) that was positive for malignant cells or by LM enhancement on magnetic resonance imaging with gadolinium contrast. Retrospective, landmark analyses were performed to estimate survival. Statistical analyses were performed using SAS Enterprise Guide, version 4.3.LM was identified in 30 patients. All cases were adenocarcinoma; 60% of patients had a known or suspected driver mutation. The mean age was 58 years. Of the 30 patients, 67% were women; 70% were nonsmokers; 27% initially presented with LM; 84% received systemic treatment at or after development of LM; and 53% of these patients received modern systemic therapy for their LM, defined as a regimen containing pemetrexed, bevacizumab, or a tyrosine kinase inhibitor. Mean overall survival after LM diagnosis was 6 months (95% CI, 3-12). Patients who received modern systemic therapy for LM had decreased hazard of death (hazard ratio [HR], 0.24; P = .007).In this retrospective, single-institution analysis, median survival with LM was higher compared with historical experience. Patients who received modern systemic therapy for their LM had particularly good outcomes. These data provide evidence for improving survival outcomes in the modern treatment era for this difficult-to-treat complication.

    View details for DOI 10.1016/j.cllc.2013.12.009

    View details for PubMedID 24524822

  • Association of Developmental Venous Anomalies with Perfusion Abnormalities on Arterial Spin Labeling and Bolus Perfusion-Weighted Imaging. Journal of neuroimaging : official journal of the American Society of Neuroimaging Iv, M., Fischbein, N. J., Zaharchuk, G. 2014

    Abstract

    To investigate the frequency and characteristics of developmental venous anomaly (DVA)-associated perfusion abnormalities on arterial spin labeling (ASL) and bolus perfusion-weighted imaging (PWI) and discuss their potential causes.We reviewed brain MR reports to identify all DVAs reported on studies performed between 2009 and 2012. DVA location and findings on PWI and/or ASL imaging were assessed by visual inspection. Sizes of DVAs were categorized as small (<15 mm), medium (15-25 mm), and large (>25 mm). For ASL, signal in the DVA, surrounding parenchyma, or associated draining vein was recorded. For PWI, changes on hemodynamic maps (cerebral blood volume [CBV], cerebral blood flow [CBF], mean transit time [MTT], and normalized time-to-peak of the residue function [Tmax]) were evaluated. Coexisting vascular malformations in association with DVAs were also identified.Six hundred and fifty-two DVAs were identified in 632 subjects. Of these, 121 underwent both perfusion modalities, 15 only PWI, and 127 only ASL. ASL abnormalities were seen in 21/248 (8%), including signal in a draining vein (2/21, 10%), in the DVA (11/21, 52%), and in the parenchyma (8/21, 38%). On PWI, the majority of DVAs demonstrated abnormalities (108/136, 79%), typically increased CBF, CBV, MTT, and Tmax. There was no association between DVA size and presence of ASL signal (P = .836). Borderline statistical significance was found between DVA size and presence of PWI abnormality (P = .046). No relationship was found between the presence of a coexisting vascular malformation and presence of ASL (P = .468) or PWI abnormality (P = .745).Perfusion changes with DVAs are common on PWI but uncommon on ASL. PWI findings are expected based on the anatomy and physiology of DVAs and are accentuated by gradient echo acquisition. DVAs with intrinsic ASL signal or signal in draining veins may be associated with arteriovenous shunting (transitional lesions).

    View details for DOI 10.1111/jon.12119

    View details for PubMedID 24717021

  • Imaging Spectrum of CNS Coccidioidomycosis: Prevalence and Significance of Concurrent Brain and Spinal Disease AMERICAN JOURNAL OF ROENTGENOLOGY Lammering, J. C., Iv, M., Gupta, N., Pandit, R., Patel, M. R. 2013; 200 (6): 1334-1346

    Abstract

    The purpose of this study was to evaluate the prevalence and significance of concurrent coccidioidal brain and intraspinal disease.We conducted a retrospective imaging review of 23 patients with proven coccidioidal CNS meningitis.All patients had intracranial abnormalities, and 86% (19/22) who underwent spinal imaging had signs of intraspinal disease, including leptomeningeal enhancement (84%), arachnoiditis (63%), and cord signal abnormalities (37%); seven of 15 patients (47%) who underwent myelography had complete spinal blocks.The high prevalence of concurrent brain and intraspinal coccidioidomycosis supports a low threshold for spinal imaging.

    View details for DOI 10.2214/AJR.12.9264

    View details for Web of Science ID 000319447700046

    View details for PubMedID 23701073

  • Comparison of Readout-Segmented Echo-Planar Imaging (EPI) and Single-Shot EPI in Clinical Application of Diffusion-Weighted Imaging of the Pediatric Brain. AJR. American journal of roentgenology Yeom, K. W., Holdsworth, S. J., Van, A. T., Iv, M., Skare, S., Lober, R. M., Bammer, R. 2013; 200 (5): W437-43

    Abstract

    OBJECTIVE. Readout-segmented echo-planar imaging (EPI) has been suggested as an alternative to single-shot EPI for diffusion-weighted imaging (DWI) with reduced distortion. However, clinical comparisons of readout-segmented EPI and EPI DWI are limited by unmatched imaging parameters and reconstruction procedures. Our goal was to compare the clinical utility of generalized autocalibrating partial parallel acquisition (GRAPPA)-accelerated readout-segmented EPI DWI with GRAPPA-accelerated EPI DWI for visualization of the pediatric brain in regions prone to distortion, such as the orbit, skull base, and posterior fossa. SUBJECTS AND METHODS. Thirty consecutive patients (mean age, 7.8 years) presenting with orbital, skull base, and posterior fossa neuropathologic abnormalities were scanned at 3 T. Images were obtained using GRAPPA-accelerated readout-segmented EPI and GRAPPA-accelerated EPI with an identical scanning time, acceleration factor, target resolution, and image postprocessing procedure. The two datasets were independently reviewed by two blinded neuroradiologists. Imaging studies were evaluated for resolution, signal-to-noise ratio (SNR), contrast, distortion, lesion conspicuity, and diagnostic confidence and graded using a 7-point Likert scale (1, nondiagnostic; 7, outstanding). RESULTS. There was good reader agreement in the scores (? = 0.66; 95% CI, 0.54-0.78). The mean scores for EPI and readout-segmented EPI, respectively, were as follows: resolution, 5.0 and 6.0; SNR, 5.5 and 3.0; contrast, 3.7 and 3.2; distortion, 4.8 and 6.0; lesion conspicuity, 4.6 and 5.1; and diagnostic confidence, 4.7 and 5.4. Readout-segmented EPI was superior in resolution, distortion reduction, lesion conspicuity, and diagnostic confidence, whereas EPI scored better in SNR and contrast. Readout-segmented EPI was considered the better sequence overall in 85% of the cases. CONCLUSION. This study shows the benefits of improved resolution and reduced distortion of readout-segmented EPI in evaluating the orbit, skull base, and posterior fossa, sites of common neuropathologic abnormalities in children.

    View details for DOI 10.2214/AJR.12.9854

    View details for PubMedID 23617511

  • Informatics in Radiology Use of a Macro Scripting Editor to Facilitate Transfer of Dual-Energy X-ray Absorptiometry Reports into an Existing Departmental Voice Recognition Dictation System RADIOGRAPHICS Iv, M., Patel, M. R., Santos, A., Kang, Y. S. 2011; 31 (4): 1181-1189

    Abstract

    The process of verbally reporting or manually retyping numeric data generated at dual-energy x-ray absorptiometry (DXA) involves numerous pitfalls. With use of a macro scripting editor, a customized macro was created to automate the transfer of data generated by a DXA scanner into a structured voice recognition dictation system without requiring radiologists to type in a medical record number or accession number to identify the study. A preliminary report is generated with use of software for a DXA unit and a customized template that includes numeric and qualitative assessments of osteoporosis as well as data from prior studies if available. A customized macro is then invoked by the macro scripting editor, which selectively transfers the report from the draft document into the voice recognition dictation system, thereby producing a final structured diagnostic report. All of the radiologists surveyed to evaluate this automated method reported ease of software use and greater efficiency in report production. In addition, a random audit of the 800 DXA scans that have been reported with this technique demonstrated no reports generated under an incorrect accession number and no incorrect transfer of data. Automated DXA reporting is now the preferred method of dictation at the authors' institution and represents an inexpensive, accurate, and customizable means of DXA reporting.

    View details for DOI 10.1148/rg.314105741

    View details for Web of Science ID 000292867000023

    View details for PubMedID 21546554

  • Left ventricular ejection fraction using 64-slice CT coronary angiography and new evaluation software: initial experience BRITISH JOURNAL OF RADIOLOGY Krishnam, M. S., Tomasian, A., Iv, M., Ruehm, S. G., Salieh, R., Panknin, C., Goldin, J. G. 2008; 81 (966): 450-455

    Abstract

    The purpose of this study was to evaluate the feasibility and reliability of software-based quantification of left ventricular function using 64-slice CT coronary angiography. Data were collected from 26 subjects who underwent a 64-slice coronary CT angiography study. Two volumetric data sets at end diastole and end systole were reconstructed from each scan by means of retrospective electrocardiogram gating. Data sets were evaluated with a prototype of now commercially available software (Syngo Circulation I; Siemens Medical Solutions, Erlangen, Germany), which automatically segments the blood volume in the left ventricle after the user defines the mitral valve plane and any point within the ventricle. After segmentation of the blood pool in end systole and end diastole, the software automatically measures end systolic and end diastolic volume and calculates stroke volume and ejection fraction (EF). Two readers processed all CT data sets twice to assess for intra- and inter-observer variation. In addition, CT EF measurements were compared with those obtained by clinical echocardiography. Intra-observer variation for the calculated EF with CT were 13.6% and 15.6% for Readers 1 and 2, respectively. No significant difference in left ventricular functional parameters on CT existed between the readers (p > 0.05). A Bland-Altman plot revealed a slight mean difference between EF measurements on CT and echocardiography, with all differences falling within two standard deviations of the mean in the setting of wide limits of agreement. In conclusion, assessment of left ventricular EF from CT coronary data using the new analysis software is rapid and easy. The software is user-friendly and provides good reproducibility for EF measurements with CT.

    View details for DOI 10.1259/bjr/54748900

    View details for Web of Science ID 000257011800004

    View details for PubMedID 18347027

  • Cardiac hemangioma: Features on cardiovascular magnetic resonance JOURNAL OF CARDIOVASCULAR MAGNETIC RESONANCE Tomasian, A., Iv, M., Lai, C., Jalili, M., Krishnam, M. S. 2007; 9 (6): 873-876

    Abstract

    We present a case of cardiac capillary hemangioma in a patient who presented with a history of recurrent episodes of syncope. Cardiovascular magnetic resonance played an important role in the diagnosis of cardiac hemangioma in our patient.

    View details for DOI 10.1080/10976640701693642

    View details for Web of Science ID 000251394000007

    View details for PubMedID 18066746

  • Pyridines in cigarette smoke inhibit hamster oviductal functioning in picomolar doses REPRODUCTIVE TOXICOLOGY Riveles, K., Iv, M., Arey, J., Talbot, P. 2003; 17 (2): 191-202

    Abstract

    Past studies showed that chemicals in cigarette smoke inhibit oviductal functioning in vivo and in vitro. The purposes of this study were to identify individual toxicants in cigarette smoke solutions that inhibit various aspects of oviductal functioning and to determine their effective doses using in vitro bioassays. Solid phase extraction and gas chromatography-mass spectrometry (GC-MS) were used to identify individual chemicals in mainstream (MS) and sidestream (SS) cigarette smoke solutions. Pyridines, which were the most abundant class of compounds identified, were purchased, assayed for purity, and tested in dose-response studies on hamster oviducts. The lowest observable adverse effect level was determined for each pyridine derivative using the oocyte pick-up rate, ciliary beat frequency, and infundibular muscle contraction assays. 2-Methylpyridine, 4-methylpyridine, 2-ethylpyridine, 3-ethylpyridine, and 4-vinylpyridine were inhibitory at picomolar concentrations in all assays. This work shows picomolar doses of pyridines with single methyl or ethyl substitutions significantly inhibit oviductal functioning raising questions regarding the safety of these compounds.

    View details for DOI 10.1016/S0890-6238(02)00150-8

    View details for Web of Science ID 000182233800007

    View details for PubMedID 12642152

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