Yair Safriel

Yale-New Haven Hospital, New Haven, Connecticut, United States

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Publications (26)40.48 Total impact

  • Yair Safriel, Brian M. Dale
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    ABSTRACT: PURPOSE Homogeneous fat suppression (FS) on T2 and post contrast T1 imaging is challenging in extremity, spine and neck imaging due to field heterogeneity and/or the presence of orthopedic hardware. FS may fail completely, result in paradoxical water suppression or, sometimes worse of all, generate an image with regions of successful and failed FS on the same image. Alternatives to FS are inversion recovery (IR) or gradient, however, these may have different imaging characteristics for certain anatomy or pathology compared to Turbo Spine Echo (TSE). Dixon FS (DFS) is robust to field heterogeneity and does not alter the sequence’s imaging characteristics. METHOD AND MATERIALS Review Board approval was obtained. DFS separately acquires images where the fat and water signals are in- and opposed-phase. Field inhomogeneity changes the overall phase, but does not change the relative phase between fat and water. Therefore, DFS uses the relative phase information to suppress fat in a manner insensitive to field inhomogeneity. Over a 6 week period the following DFS was applied to: All neck MR’s, all spinal post contrast MR’s and a random selection of noncontrast spine and musculoskeletal MR’s. In all cases the DFS was obtained in addition to routine T1 or T2 FS sequence. Sequences were performed on a variety of 1.5 and 3T (Espree, Avanto and Tim Trio, Siemens, Germany). Each sequence was scored for edge artifact, FS homogeneity, metal artifact and visualization of pathology. RESULTS 34 DFS sequences (11 lumbar, 7 thoracic & 7 cervical spine, 3 joints, 3 pelvis and 3 necks) were scanned. T2 and T1 DFS scored better or equivalent to T2FS and T1FS in 97% and 100% of cases (P<0.0001) respectively. IR was superior or equivalent to T2 DFS in 96% (P<0.0001). Compared to routine sequences, edge artifact and metal artifact and field inhomogeneities were reduced on T1 and T2 DFS but worse when T2 DFS was compared to IR (P<0.011). Lesion detection evaluation was limited by the fact that not all exams had abnormal lesions. CONCLUSION DFS has potential to improve imaging of implanted hardware, on both 1.5T and 3T. It may also improve diagnostic confidence, possibly obviating additional or invasive procedures. Further work is needed to better define the parameters prior to commercial release. CLINICAL RELEVANCE/APPLICATION DFS markedly improves FS image quality in T2 & post contrast T1 sequences without altering the expected signal characteristics of anatomy or pathology
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
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    ABSTRACT: Background RTOG 0625/ACRIN 6677 is a multicenter, randomized, phase II trial of bevacizumab with irinotecan or temozolomide in recurrent glioblastoma (GBM). This study investigated whether early posttreatment progression on FLAIR or postcontrast MRI assessed by central reading predicts overall survival (OS). Methods Of 123 enrolled patients, 107 had baseline and at least 1 posttreatment MRI. Two central neuroradiologists serially measured bidimensional (2D) and volumetric (3D) enhancement on postcontrast T1-weighted images and volume of FLAIR hyperintensity. Progression status on all posttreatment MRIs was determined using Macdonald and RANO imaging threshold criteria, with a third neuroradiologist adjudicating discrepancies of both progression occurrence and timing. For each MRI pulse sequence, Kaplan-Meier survival estimates and log-rank test were used to compare OS between cases with or without radiologic progression. Results Radiologic progression occurred after 2 chemotherapy cycles (8 weeks) in 9 of 97 (9%), 9 of 73 (12%), and 11 of 98 (11%) 2D-T1, 3D-T1, and FLAIR cases, respectively, and 34 of 80 (43%), 21 of 58 (36%), and 37 of 79 (47%) corresponding cases after 4 cycles (16 weeks). Median OS among patients progressing at 8 or 16 weeks was significantly less than that among nonprogressors, as determined on 2D-T1 (114 vs 278 days and 214 vs 426 days, respectively; P < .0001 for both) and 3D-T1 (117 vs 306 days [P < .0001] and 223 vs 448 days [P = .0003], respectively) but not on FLAIR (201 vs 276 days [P = .38] and 303 vs 321 days [P = .13], respectively). Conclusion Early progression on 2D-T1 and 3D-T1, but not FLAIR MRI, after 8 and 16 weeks of anti-vascular endothelial growth factor therapy has highly significant prognostic value for OS in recurrent GBM.
    Neuro-Oncology 07/2013; 15(7):945-954. · 6.18 Impact Factor
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    ABSTRACT: Background The prognosis for patients with recurrent glioblastoma remains poor. The purpose of this study was to assess the potential role of MR spectroscopy as an early indicator of response to anti-angiogenic therapy.Methods Thirteen patients with recurrent glioblastoma were enrolled in RTOG 0625/ACRIN 6677, a prospective multicenter trial in which bevacizumab was used in combination with either temozolomide or irinotecan. Patients were scanned prior to treatment and at specific timepoints during the treatment regimen. Postcontrast T1-weighted MRI was used to assess 6-month progression-free survival. Spectra from the enhancing tumor and peritumoral regions were defined on the postcontrast T1-weighted images. Changes in the concentration ratios of n-acetylaspartate/creatine (NAA/Cr), choline-containing compounds (Cho)/Cr, and NAA/Cho were quantified in comparison with pretreatment values.ResultsNAA/Cho levels increased and Cho/Cr levels decreased within enhancing tumor at 2 weeks relative to pretreatment levels (P = .048 and P = .016, respectively), suggesting a possible antitumor effect of bevacizumab with cytotoxic chemotherapy. Nine of the 13 patients were alive and progression free at 6 months. Analysis of receiver operating characteristic curves for NAA/Cho changes in tumor at 8 weeks revealed higher levels in patients progression free at 6 months (area under the curve = 0.85), suggesting that NAA/Cho is associated with treatment response. Similar results were observed for receiver operating characteristic curve analyses against 1-year survival. In addition, decreased Cho/Cr and increased NAA/Cr and NAA/Cho in tumor periphery at 16 weeks posttreatment were associated with both 6-month progression-free survival and 1-year survival.Conclusion Changes in NAA and Cho by MR spectroscopy may potentially be useful as imaging biomarkers in assessing response to anti-angiogenic treatment.
    Neuro-Oncology 05/2013; · 6.18 Impact Factor
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    ABSTRACT: PURPOSE RTOG 0625/ACRIN 6677 is a multi-center randomized phase II trial of bevacizumab (an anti-VEGF antibody) with irinotecan or temozolomide in recurrent GBM. The frequency of pseudoresponse in patients receiving VEGF blockade has raised concerns that radiologic response may not predict overall survival (OS). This study aimed to determine if progression on FLAIR or post-Gd 2D-T1 or 3D-T1 MRI after 2 or 4 anti-VEGF chemotherapy cycles (8 or 16 weeks) is predictive of OS. METHOD AND MATERIALS Of 123 enrolled patients (71 men, 52 women; ages 23-87 years, median 56), 107 had baseline and at least one post-treatment MRI (after every 2 treatment cycles or 8-week blocks). Two central readers serially measured bidimensional (2D) and volumetric (3D) enhancement on post-Gd T1-weighted images, and 3D FLAIR hyperintensity. Progression status on all post-treatment MRIs was determined using Macdonald criteria, with adjudication of discrepancies by a third reader. All readers had neuroradiology CAQ and were carefully trained and tested to reduce reader variance. Survival and censorship were defined with respect to enrollment date. Kaplan-Meier survival estimates and log-rank test were used to compare the overall survival for cases with or without radiologic progression. RESULTS Overall adjudication rates for time of progression were 43% (n=45) for 2D-T1, 42% (n=32) for 3D-T1, and 39% (n=42) for FLAIR. Excluding patients missing relevant scans or with precedent death, there was radiologic progression at 8 weeks in 9/97 (9%), 9/73 (12%), and 11/98 (11%) evaluable 2D-T1, 3D-T1, and FLAIR cases, respectively, and in 34/80 (43%), 21/58 (36%), and 37/79 (47%) corresponding cases at 16 weeks. The median OS (days) for patients with progression at 8 or 16 weeks was significantly less than that for patients without progression on 2D-T1 (114 vs. 278 and 214 vs. 426, p<0.0001 for both) and 3D-T1 (117 vs. 306, p<0.0001 and 223 vs. 448, p=0.0003), but not FLAIR (201 vs. 276, p=0.38 and 303 vs. 321, p=0.13). CONCLUSION Early progression on post-Gd 2D-T1 and 3D-T1, but not FLAIR MRI after 2 and 4 cycles (8 and 16 weeks) of anti-VEGF therapy has highly significant prognostic value for OS. Funded by NCI U01-CA080098 and U01-CA079778. CLINICAL RELEVANCE/APPLICATION Early post-therapy progressive 2D-T1 and 3D-T1 enhancement may be a useful MRI biomarker for the failure of anti-VEGF therapy, permitting a timely switch to alternative trials when necessary.
    Radiological Society of North America 2012 Scientific Assembly and Annual Meeting; 11/2012
  • Yair Safriel, Brian M. Dale
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    ABSTRACT: PURPOSE The presence of blood products may make it difficult to discern contrast enhancement on Gadolinium contrast enhanced (CE) T1 sequences (T1C+) of the brain. We propose to evaluate whether CE Susceptibility Weighted Imaging (CE SWI) is technically feasible and if it can be helpful in hemorrhagic intracranial conditions. METHOD AND MATERIALS All patients who undergo a CE brain MRI in our institution have a CE SWI sequence performed routinely. We retrospectively selected 19 random scans where patients had a significant finding diagnosed (mass, hemorrhage, infarct or abscess). A set of pre contrast T1 & T1C+ as well as CE SWI sequences were available on all cases. We compared the visualization of enhancement and hemorrhage on the T1 set and SWI. We also compared if differentiating enhancement on the background of hemorrhage was better discerned on the T1 set or the CE SWI. All diagnoses were confirmed with either biopsy or adequate follow up. RESULTS 19 scans were performed on 18 patients (10 males & 8 females). 1 patient was scanned twice, before surgery and after removal of a lymphoma. Performing CE SWI post contrast administration did not result in quality issues in any exam. There were 6 grade IV gliomas, 3 lymphomas, 2 cases of cerebral amyloid angiopathy (1 with a coexistent infarct), 2 additional infarcts (1 with coexistent Moya-Moya), 1 bland hypertensive hemorrhage, one melanoma metastasis, 1 ependymoma, one Norcadia abscess and 1 AVM. In 3 scans there was no hemorrhage and in 4, no enhancement on any sequences. The T1 sets demonstrated only fair agreement with CE SWI for detecting hemorrhage (kappa=0.39, p=0.033, sensitivity=60%, specificity=100%). CE SWI was superior or equal to T1 set in the discrimination of enhancement within hemorrhage in 17 scans and the T1 set superior in 2 scans (p=0.004). The CE SWI demonstrated very good agreement with the T1 sets for detecting enhancement (kappa=0.83, p<0.001, sensitivity=94%, specificity=100%). CONCLUSION CE SWI scans can be successfully performed after the administration of contrast. CE SWI is superior to a T1 set in detecting hemorrhages and identifying enhancement within a hemorrhagic background. There are, however, situations where the T1 set was superior to the SWI sequence. CLINICAL RELEVANCE/APPLICATION CE SWI can detect lesions camouflaged by hemorrhage that would be otherwise obscured.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 12/2011
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    ABSTRACT: PURPOSE To evaluate demographic and imaging findings that predict near term response to Epidural Steroid Injections (ESI) measured in a controlled environment. In this initial analysis we evaluated response to ESI in single level vs. multilevel spinal stenosis, the effect of facet degeneration without & with spinal stenosis, response in spinal stenosis caused by herniation vs. multifactorial spondylosis and the effect of herniation size. We also compared interlaminar (IL) injections given above vs. at the level of maximal stenosis and compared relief for transforaminal (TF) injections relative to stenosis. METHOD AND MATERIALS We randomly extracted records of patients who had lumbar ESI’s from 2004 -2009 and a MRI. Relief was evaluated using a numeric rating scale in a controlled environment. Text records were converted to numeric values with an computerized parser. The parser segmented injection type, volumes, response, herniation size & location and the degree of central, subarticular and foraminal stenosis at each level between T12-L1 and L5-S1. Segments which the parser could not resolve were reviewed manually. The data was analyzed by our Six Sigma team using a combination of multiple statistical tests. RESULTS 3001 patients had 4378 injections in 11 centers. Subjects over 65 years old had better response than other age groups (p=.002) independent of herniation size or number of levels with stenosis. TF injections had better results than IL injections (p=.000) with L5-S1 injection yielding best relief (p=.002). Younger patients tended to receive TF rather than IL injections. Despite that, patients over 65 still showed better response. TF injections given at or below the level of maximal stenosis (LMS) provided marginally better relief than above the LMS (p=.053). MRI availability prior to the procedure was marginally associated with better relief (p=.072). There degree of central stenosis, coexistent facet disease, herniation size or single versus multilevel disease did not influence relief. CONCLUSION Initial analysis of this multicenter, large, population based cohort shows significant relief in the over 65 age group and in TF injections. We are presently analyzing additional outcome and technical end-points. CLINICAL RELEVANCE/APPLICATION It is necessary to identify factors that predict response to epidural steroid injections (ESI) so as to allow individual patients to receive appropriate, cost effective care.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 11/2010
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    ABSTRACT: PURPOSE Bevacizumab, an anti-VEGF antibody, was recently approved by the FDA for recurrent glioblastoma (GBM), the first successful use of a targeted therapy in malignant glioma. Central radiology review of brain MRI was key in the approval. However, the two radiology reviewers disagreed about progression - 25% increase in size in T1-weighted (T1w) enhancement - in ~50% of MRI scans. Furthermore, since VEGF blockade might diminish tumor enhancement despite tumor growth concern, T2-weighted imaging (T2w) may be more informative in assessing tumor progression. We undertook central radiological review in a multicenter clinical trial to address these two issues. METHOD AND MATERIALS RTOG 0625 / ACRIN 6677 is a randomized Phase II trial of bevacizumab with either irinotecan or dose-dense temozolomide in recurrent GBM. Central radiology review was performed using WHO-style bidimensional radiographic assessment of progression, serial 3D volume (both on T1w post contrast images), and 3D volume of T2w images. Two readers and an adjudicator (all CAQ’d neuroradiologists) were carefully trained and tested to reduce reader variance. The six month progression-free survival (PFS-6) rate and adjudication rate was calculated for 2D, 3D-T1, and 3D-T2 separately and together. RESULTS Central review has been completed to date on 51 cases of 123 patients enrolled. Adjudication rates were 33% for 2D (n=48), 29% for 3D-T1 (n=34), and 33% for 3D-T2 (n=43), substantially lower than the published figure of 44 to 47% in previous bevacizumab trials, suggesting the benefits of training. PFS-6 was similar for all three methods: 2D: 33%; 3D-T1: 32%; 3D-T2: 26%. However, combining the methods led to increased rates of progression: using T2 or T1 imaging, progression occurred in 8/42 cases for 2D T1 imaging (PFS-6=12%, p=0.005) and 5/29 cases for 3D-T1 imaging (PFS-6=14%, p=0.025). Combining all three (n=28) led to PFS-6 of 7% (p=0.046 vs 2D alone, p=0.008 vs 3D T1 alone). CONCLUSION Addition of T2 imaging increases progression rates in recurrent GBM patients being treated with anti-VEGF therapy. Funded by the National Cancer Institute through grant U01-CA80098. CLINICAL RELEVANCE/APPLICATION Monitoring of T2 imaging increases the detection rate of GBM progression after treatment with anti-VEGF agents. The clinical relevance of this needs further study.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 11/2010
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    Yair Safriel, Roberto Ang, Muhammed Ali
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    ABSTRACT: Introduction. To review the safety and efficacy of gadolinium in spine pain management procedures in patients at high risk for a contrast reaction and who are not suitable candidates for the use of standard non-ionic contrast. Methods. We reviewed records over a 61-month period of all image-guided spinal pain management procedures where patients had allergies making them unsuitable candidates for standard non-ionic contrast and where gadolinium was used to confirm needle tip placement prior to injection of medication. Results. Three hundred and four outpatients underwent 527 procedures. A spinal needle was used in all but 41 procedures. Gadolinium was visualized using portable C-arm fluoroscopy in vivo allowing for confirmation of needle tip location. The gadolinium dose ranged from 0.2 to 10 ml per level. The highest dose received by one patient was 15.83 ml intradiscally during a three-level discogram. Three hundred and one patients were discharged without complication or known delayed complications. One patient had documented intrathecal injection but without sequelae and 2 patients who underwent cervical procedures experienced seizures requiring admission to the intensive care unit. Both the latter patients were discharged without any further complications. Conclusion. Based on our experience we recommend using gadolinium judiciously for needle tip confirmation. We feel more confident using gadolinium in the lumbar spine and in cervical nerve blocks. Gadolinium should probably not be used as an injectate volume expander. The indications for gadolinium use in cervical needle-guided spine procedures are less clear and use of a blunt-tipped needle should be considered.
    CardioVascular and Interventional Radiology 07/2009; · 2.09 Impact Factor
  • Yair Safriel, Olga Alex Lopatina
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    ABSTRACT: PURPOSE Cervical interlaminar epidural steroid injections (CIESI) can generally be safely performed at C7-T1 or, rarely at C6-7. This is due to the small epidural space and the subsequent danger of intrathecal injection above that. Yet in many patients it is difficult or impossible to visualize the small needles used on lateral fluoroscopy due to shoulders and other tissues. To overcome this limitation, we evaluated the safety and utility of an oblique fluoroscopically guided technique for outpatient CIESI that obviates the need for lateral fluoroscopy. METHOD AND MATERIALS 172 patients underwent fluoroscopically guided CIESI using a posterior oblique approach. The patients were placed prone with a support under the forehead or chest so as to ensure that the neck was either neutral or slightly flexed. The C-arm was then rotated approximately 5 degrees towards the operator and approximately 5 degrees caudate. A trajectory leading to the apex of the interlaminar space was marked on the skin. A needle was then advanced under fluoroscopic control and its progress monitored in the AP projection and in a projection approximately 25 degrees from midline obliqued away from the operator. Once the needle tip was near the spinolaminar line, test injections with radio-opaque contrast were performed until epidural opcification obtained. Midline needle placement was also documented on the AP projection. Epidurography was performed on all patients. All clinically significant complications other than skin discoloration or temporary local symptoms related to needle passage were recorded. RESULTS There were no cases where the injectate was either outside the epidural space or intrathecal. There were no immediate complications. All patients were discharged uneventfully without delayed reported complications. All patients had needle tip imaged at all times in two planes without the need for lateral fluoroscopy. 25G Quinke needles were used in 78 cases, 22G Quinke needles in 4 cases and 22G Whitacre needles in 90 cases. There were 165 C7-T1 procedures, five C6-7 procedures and one each at C5-6 and T1-T2. CONCLUSION The oblique CIESI approach described is safe & reliable and is now routinely used in the authors practice. CLINICAL RELEVANCE/APPLICATION This technique allows safe & reliable needle placement in the epidural space in patients of all sizes without added time or risk. It will allow many more patients to successfully undergo CIESI.
    Radiological Society of North America 2008 Scientific Assembly and Annual Meeting; 12/2008
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    Yair Safriel, Frank Hull
    The Yale journal of biology and medicine 06/2005; 78(3):157-71.
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    ABSTRACT: West Nile virus (WNV) infection is an ongoing seasonal epidemic. We correlated the MR imaging findings with the clinical presentations and outcomes of WNV infection. We reviewed 14 brain and three spinal MR images: nonenhanced and contrast-enhanced T1-weighted images (T1WIs) and T2-weighted images (T2WIs), nonenhanced fluid-attenuated inversion recovery (FLAIR) images (11 patients) and enhanced FLAIR images (three patients), with diffusion-weighted (DW) images and apparent diffusion coefficient maps. WNV infection was diagnosed by means of enzyme-linked immunosorbent assay with a plaque reduction neutralization test. We also correlated the MR findings with the clinical presentation, course, and outcome to determine their prognostic importance. MR imaging findings included: 1) normal (five patients); 2) DW imaging-only abnormalities in the white matter, corona radiata, and internal capsule (four patients); 3) hyperintensity on FLAIR images and T2WIs in the lobar gray and white matter, cerebellum, basal ganglia, thalamus and internal capsule, pons and midbrain (three patients); 4) meningeal involvement (two patients); and 5) spinal cord, cauda equina, and nerve root involvement (three patients). All patients with finding 1 and all but one with finding 2 recovered completely. Two patients with finding 3 died. Those with finding 4 or 5 had residual neurologic deficits that were severe or moderate to severe, respectively. Patients with normal MR images or abnormalities on only DW images had the best prognosis, while those with abnormal signal intensity on T2WI and FLAIR images had the worst outcomes. No definite predilection for any specific area of the brain parenchyma was noted.
    American Journal of Neuroradiology 03/2005; 26(2):289-97. · 3.17 Impact Factor
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    ABSTRACT: PURPOSE Digital subtraction of cerebral magnetic resonance (MR) images has benefited where lesional T1 shortening masks potential enhancement. Similar benefits may be obtained when imaging the spine, shown only on one report of the post operative spine. We will illustrate the clinical utility of complex digital subtraction when imaging the spine with MR. METHOD AND MATERIALS Over the course of a 6 month period, complex digital subtraction was used in routine clinical cases where enhancement was potentially masked by other findings. Post processing was done offline at the MR console (General Electric, Milwaukee, WI) by the technologist. All sequences were reviewed by three neuroradiologists, as part of routine practice. RESULTS In all, 13 spinal MR exams were reviewed from 12 patients. Lesions within the canal were studied, including primary spinal tumor, hemorrhage within the cord, dural based inflammatory, and metastatic processes. Post operative changes, trauma, and extent of disease in the vertebral bodies were also evaluated. Imaging where there was no fat saturation also potentially hindered T1 shortening from contrast, lending such cases to subtraction. CONCLUSIONS Our study demonstrates the necessity for subtracting MR images of the spine in order to accurately assess for enhancement. This was most pronounced when evaluating for extramedullary enhancement as well as vertebral body disease. Complex digital subtraction will save time by excluding fat suppressed imaging, while allowing for accurate assessment for enhancement.
    Radiological Society of North America 2004 Scientific Assembly and Annual Meeting; 11/2004
  • Journal of Vascular and Interventional Radiology 02/2004; 15(1 Pt 1):7-12. · 2.00 Impact Factor
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    ABSTRACT: The purpose of this study was to determine whether the presence of hematuria or its absence can predict the presence or absence of urinary calculi as determined by computed tomography (CT) scan in patients presenting to the ED with acute abdominal colic. We reviewed the urine analysis and CT scans of all patients presenting to the ED over a 12-month period with acute colic and a clinical suspicion of urinary calculi. Urine samples were drawn on arrival in the ED before CT scanning. Two hundred seventy-seven patients were included in the study. The prevalence of urinary stones as detected by CT was 57.4%. The positive predictive value, negative predictive value, and accuracy for hematuria as a marker for stone disease was 60.9%, 72.4%, and 62.1%, respectively. A total of 3.24% of patients had some degree of obstruction, all of whom had hematuria. The absence of hematuria is not a reliable exclusion criterion for urinary calculi. The detection of urinary stones without hematuria does not imply obstruction.
    American Journal of Emergency Medicine 11/2003; 21(6):492-3. · 1.70 Impact Factor
  • Academic Radiology 06/2003; 10(5):565-6. · 1.91 Impact Factor
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    ABSTRACT: Traditionally giant splenic artery aneurysms have been treated by surgery. We present the first case report of a patient with a giant splenic artery aneurysm that was successfully treated exclusively by transcatheter technique with only proximal embolization. Potentially, this technique makes more patients eligible for endovascular therapy and reduces operative time.
    International Journal of Angiology 01/2003; 12(3):209-210.
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    ABSTRACT: Computed tomography (CT) is the accepted frontline imaging modality for blunt abdominopelvic trauma. However, urethral injuries are traditionally diagnosed with retrograde urethrography. The CT appearances of urethral injuries and the signs associated with posterior urethral injuries are not well described in the literature. CT scans of patients with pelvic fractures and urethrographically proved posterior urethral injuries were evaluated. CT scans of patients with similar pelvic fractures who did not have urethral injuries were also evaluated. The CT findings of elevation of the prostatic apex, extravasation of urinary tract contrast material above the urogenital diaphragm (UGD), and extravasation of urinary tract contrast material below the UGD were specific for type I, II, and III urethral injuries, respectively. If extraperitoneal bladder rupture is present along with periurethral extravasation of contrast material, the possibility of type IV and IVA urethral injuries should be considered. In addition, the CT findings of distortion or obscuration of the UGD fat plane, hematoma of the ischiocavernosus muscle, distortion or obscuration of the prostatic contour, distortion or obscuration of the bulbocavernosus muscle, and hematoma of the obturator internus muscle were more common in patients with pelvic fractures and associated urethral injuries than in patients with uncomplicated pelvic fractures.
    Radiographics 01/2003; 23(4):951-63; discussion 963-6. · 2.79 Impact Factor
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    ABSTRACT: A case report with a review of the literature is presented demonstrating the imaging findings of a patient with recent onset, progressive spinal cord compression at T6 caused by a giant arachnoid cyst that was successfully treated. To present the imaging findings of a giant anterior cervicothoracic intradural arachnoid cyst using several methods before and after treatment. This case demonstrates the imaging findings of the largest described anterior cervical arachnoid cyst straddling the cervicothoracic junction. It presented with spinal cord compression in a 26-year-old diagnosed by MRI and successfully treated surgically. The patient experienced progressive left-sided sensory and motor deficits below T6. Pain and temperature sensation were decreased. Reflexes were increased in both lower extremities with clonus. Preoperative MRI was followed by laminectomy and cyst fenestration with subsequent postoperative myelogram and CT. Imaging confirmed the presence of a giant arachnoid cyst straddling the cervicothoracic junction. Postoperative imaging documented relief of spinal cord compression. Symptoms improved progressively after surgery. By the time of discharge all residual neurologic deficits had resolved. Anterior arachnoid cysts straddling the cervicothoracic junction have yet to be reported, and arachnoid cysts involving the cervical region are extremely rare. Imaging demonstrated the cyst and its response to treatment. This patient responded well to surgery and was discharged without neurologic sequelae.
    Spine 09/2002; 27(15):E366-8. · 2.16 Impact Factor
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    ABSTRACT: CT pulmonary angiography is now often the first-line investigation for pulmonary emboli. When these studies are performed after hours in teaching hospitals, they are often initially interpreted by trainees. It is of great significance whether the interpretations of trainees and certified radiologists with regard to the presence of pulmonary emboli on CT pulmonary angiograms correspond, because of the morbidity and mortality of both the condition and its treatment. Twenty-five consecutive CT pulmonary angiograms (CTPAs) of hospitalized patients were viewed at lung and soft tissue windows both on a workstation and on hard copies, at the observers' discretion. Each CTPA was divided into 28 arterial zones based on pulmonary anatomy (including the subsegmental arteries), giving a total of 700 arterial zones, and analyzed retrospectively and independently by two cross-sectional imaging specialists and four residents. Each arterial segment was rated with regard to pulmonary embolus as either high, intermediate, or low probability or not visualized. The kappa (Kappa) test, which tests for interobserver agreement, was used for statistical analysis. At the time of the scan all patients were hospitalized for underlying conditions. Of the 25 patients studied, 9 were referred from the ICU, 7 experienced severe acute shortness of breath and respiratory failure, 5 were post-partum women, 2 had had a recent stroke, 1 patient had antithrombin III deficiency, and 1 had a diagnosis of breast cancer. The incidence of pulmonary emboli was 44%. For the main pulmonary arteries interobserver agreement was good (Kappa=0.61) and for the segmental pulmonary arteries it was fair (Kappa=0.26). For the subsegmental arteries interobserver agreement was poor (Kappa=0.16). The zones where interobserver agreement was greatest (Kappa>0.4) were the left main, left lower lobe, and the right main pulmonary arteries. Interobserver agreement was poorest (Kappa<0.05) in the left interlobar, left lower lobe lateral basal segment, right lower lobe superior segment, and left lower lobe superior segment branches. None of the patients expired due to pulmonary emboli. Most life-threatening pulmonary emboli requiring urgent treatment are the more central emboli. This study demonstrates that trainees and certified radiologists can make similar conclusions regarding these central pulmonary emboli in hospitalized patients and that preliminary interpretations by trainees should not therefore adversely affect patient care.
    Emergency Radiology 04/2002; 9(1):55-9.
  • Yair Safriel, Harry Zinn
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    ABSTRACT: To determine the overall sensitivity and specificity for CT pulmonary angiography (CTPA) in the diagnosis of pulmonary emboli (PE) using a meta-analysis of the published literature. A Medline search was constructed to include all English language publications indexed in the Index Medicus from 1990 to 2000, which included the terms CT, PE and pulmonary angiography. Studies selected were designed principally to compare CTPA in the overall detection of PE as confirmed by an abnormal fluoroscopic pulmonary angiogram or a high probability V:Q scan. Results were corrected for the patient sample size in the respective studies prior to pooling the data. In the absence of an accepted technique for calculating a ROC curve in the meta-analysis of imaging studies, a previously untested theoretical technique was used to obtain a composite ROC curve. Twelve studies of CTPA comprising a total of 1250 patients were analyzed. The overall sensitivity and specificity for CTPA after correction for study size was 74.1% and 89.5% with a range of 57-100% and 68-100%, respectively, for the detection of PE. No trend was detected with respect to the year of publication or sample size. CTPA has acceptable sensitivity and specificity with a strong ROC curve making it a good first line investigation for PE.
    Clinical Imaging 01/2002; 26(2):101-5. · 0.65 Impact Factor

Publication Stats

163 Citations
40.48 Total Impact Points


  • 2003–2009
    • Yale-New Haven Hospital
      New Haven, Connecticut, United States
  • 2002–2003
    • Yale University
      • Section of Nephrology
      New Haven, CT, United States
    • City University of New York - Brooklyn College
      Brooklyn, New York, United States
    • State University of New York Downstate Medical Center
      • Department of Radiology
      Brooklyn, NY, United States