Faculty Bibliography

The significant advances in magnetic resonance imaging (MRI) hardware and software, sequence design, and postprocessing methods have made diffusion-weighted imaging (DWI) an important part of body MRI protocols and have fueled extensive research on quantitative diffusion outside the brain, particularly in the oncologic setting. In this review, we summarize the most up-to-date information on DWI acquisition and clinical applications outside the brain, as discussed in an ISMRM-sponsored symposium held in April 2015. We first introduce recent advances in acquisition, processing, and quality control; then review scientific evidence in major organ systems; and finally describe future directions. J. Magn. Reson. Imaging 2016.

Purpose To determine the interobserver reproducibility of the Prostate Imaging Reporting and Data System (PI-RADS) version 2 lexicon. Materials and Methods This retrospective HIPAA-compliant study was institutional review board-approved. Six radiologists from six separate institutions, all experienced in prostate magnetic resonance (MR) imaging, assessed prostate MR imaging examinations performed at a single center by using the PI-RADS lexicon. Readers were provided screen captures that denoted the location of one specific lesion per case. Analysis entailed two sessions (40 and 80 examinations per session) and an intersession training period for individualized feedback and group discussion. Percent agreement (fraction of pairwise reader combinations with concordant readings) was compared between sessions. kappa coefficients were computed. Results No substantial difference in interobserver agreement was observed between sessions, and the sessions were subsequently pooled. Agreement for PI-RADS score of 4 or greater was 0.593 in peripheral zone (PZ) and 0.509 in transition zone (TZ). In PZ, reproducibility was moderate to substantial for features related to diffusion-weighted imaging (kappa = 0.535-0.619); fair to moderate for features related to dynamic contrast material-enhanced (DCE) imaging (kappa = 0.266-0.439); and fair for definite extraprostatic extension on T2-weighted images (kappa = 0.289). In TZ, reproducibility for features related to lesion texture and margins on T2-weighted images ranged from 0.136 (moderately hypointense) to 0.529 (encapsulation). Among 63 lesions that underwent targeted biopsy, classification as PI-RADS score of 4 or greater by a majority of readers yielded tumor with a Gleason score of 3+4 or greater in 45.9% (17 of 37), without missing any tumor with a Gleason score of 3+4 or greater. Conclusion Experienced radiologists achieved moderate reproducibility for PI-RADS version 2, and neither required nor benefitted from a training session. Agreement tended to be better in PZ than TZ, although was weak for DCE in PZ. The findings may help guide future PI-RADS lexicon updates. (c) RSNA, 2016 Online supplemental material is available for this article.

PURPOSE: The purpose of the article is to characterize the diagnostic errors in abdominopelvic CT interpretation through review of radiology report addenda. METHODS: We searched abdominopelvic CT reports for the word "addendum" over a nearly seven-year period. Addenda were reviewed to identify those reporting a diagnostic error. Cases were characterized by a spectrum of features. RESULTS: 709 addenda describing 785 diagnostic errors were identified, representing approximately 0.5% of searched reports. 84.1% were a new finding, 5.1% an upgrade in severity of an originally reported finding, 3.9% a downgrade in severity, and 6.9% other modification. The most common anatomic sites, as well as the most common missed abnormality per site, were vasculature (9.8%, atherosclerosis/thrombus), abdominal wall (8.3%, ventral hernia), bone [7.4%, osseous lesion (not clearly benign)], kidney [6.9%, renal lesion (not clearly benign)], liver (6.1%, steatosis), and ureter (5.1%, calculus). Of 209 addenda providing a reason for the change, 30.6% related to comparison with prior imaging, 22.5% additional surgical history, 13.4% referrer request for re-review, 8.6% additional signs, symptoms, or lab abnormality, 8.6% additional known diagnosis, 5.7% attention to patient gender, 5.3% multi-planar reconstructions, and 5.3% consultation with other radiologist. CONCLUSION: Missed findings rather than misinterpretations of detected abnormalities were the most common reason for abdominopelvic CT report addenda. Awareness of the most common misses by anatomic location may help guide quality assurance initiatives. A wide variety of contributing factors were identified. Informatics and workflow optimization may be warranted to facilitate radiologists' access to all available patient-related data, as well as communication with other physicians, and thereby help reduce diagnostic errors.

PURPOSE: The aim of this study was to report the investigators' preliminary experience in the implementation of a "virtual consult" (VC) system enabling consultations between radiologists and referring physicians in physically remote locations throughout their enterprise. METHODS: Referrers and radiologists directly access the VC through the electronic medical record and PACS, respectively. Referrers may click a VC link associated with any examination report to instant message the appropriate subspecialist radiologist, who receives an alert allowing automatic loading of the examination. The radiologist and referrer may then discuss the examination via instant messaging as well as launch a real-time screen-share of the radiologist's PACS display, with the option for either participant to control the display. Radiologists' and referrers' feedback was evaluated after the institution's first 110 VC sessions. RESULTS: Referrers' most common specialties were emergency medicine (27.3%) and internal medicine (13.6%); radiologists' most common subspecialties were abdominal (33.6%) and thoracic (16.4%) imaging. Screen-shares lasted on average 12 +/- 16 minutes. From 80% to 90% of referrers agreed that the VC was easy to use, improved their understanding of the radiology report, affected patient management, and enhanced radiologists' role. Referrers found the VC to be particularly useful when traditional consultation was difficult because of location or time constraints or when seeking a quick response to a targeted question. Radiologists recognized referrers' positive response to the VC, although they tended to view the VC as disruptive to normal workflow. CONCLUSIONS: The VC addresses a key challenge in the current era of digital radiology practice and provides added value to referrers, though continued radiologists' workflow optimization is warranted.

RATIONALE AND OBJECTIVES: This study aimed to characterize associations between availability of imaging services and intensity of teaching among US hospitals. MATERIALS AND METHODS: Using the American Hospital Association Annual Survey Database, we studied information regarding the availability of imaging services at general hospitals nationwide in 2007 (4102 hospitals) and in 2012 (3876). Teaching intensity was categorized as Council of Teaching Hospitals (COTH) member, non-COTH teaching hospital (non-COTH member with affiliated medical school and/or residency), and nonteaching hospital. Availability in hospitals of reported basic and advanced imaging modalities, as well as beds, number of employed physicians, and case mix index, was analyzed. Univariable and multivariable trends were assessed. RESULTS: All 15 assessed modalities showed significant increases in availability with increasing hospital teaching intensity (P < 0.001). Modalities showing the largest differences between COTH and nonteaching hospitals in 2012 were image-guided radiation therapy (78% vs. 14%), positron emission tomography/computed tomography (74% vs. 17%), and single-photon emission computed tomography (88% vs. 35%). The gap between COTH and nonteaching hospitals increased from 43% in 2007 to 57% in 2012 for positron emission tomography/computed tomography, and from 34% to 48% for virtual colonoscopy. COTH status was a significant predictor, independent of beds and employed physicians, for 10 modalities (P < 0.001-0.038). Greater case mix index was significantly associated with availability of advanced, although not basic, modalities. CONCLUSIONS: Availability of imaging services increased with greater hospital teaching intensity. Differences were most pronounced and sustained over time for advanced modalities. Our findings reflect the greater advanced imaging resources necessary to support the complexity of care rendered at teaching hospitals. This differential must be considered when exploring adjustments to teaching hospitals' funding levels.

OBJECTIVE: Our study aimed to retrospectively evaluate the utility of volumetric histogram-based diffusion metrics in differentiating benign from malignant endometrial abnormalities. METHODS: A total of 54 patients underwent pelvic magnetic resonance imaging with diffusion-weighted imaging before endometrial tissue diagnosis. Two radiologists placed volumes of interest on the apparent diffusion coefficient (ADC) map encompassing the entire endometrium and focal endometrial lesions. The mean ADC, percentile ADC values, kurtosis, skewness, and entropy of ADC were compared between benign and malignant abnormalities. RESULTS: In premenopausal patients, significant independent predictors of malignancy were whole-endometrium analysis for R1, 10th to 25th ADC percentile (P = 0.012); whole-endometrium analysis for R2, mean ADC (P = 0.001) and skewness (P = 0.004); focal lesion analysis for R1, skewness (P = 0.045); focal lesion analysis for R2, 10th to 25th ADC percentile (P