Faculty Bibliography

OBJECTIVES/OBJECTIVE:To assess the inter-reader variability in response assessment for HCC treated with radioembolization (TARE) compared with 3D quantitative criteria (qEASL); and to evaluate their role in prediction of pathological necrosis and clinical outcomes. MATERIALS AND METHODS/METHODS:57 patients with 77 HCCs who underwent TARE were included. Five radiologists recorded multiple imaging features and assigned mRECIST/LIRADS Treatment Response (TR) categories on post-treatment MRI at 4-6 weeks and 6-9 months after TARE. qEASL categories were assigned by a separate reader. Inter-reader variability between LIRADS TR/mRECIST/qEASL were evaluated and hazards regression was used in predicting clinical outcomes. RESULTS:Inter-reader agreement was fair for mRECIST (K = 0.43 and 0.34 at first and second follow-up respectively); moderate for LIRADS TR (K = 0.48 and 0.53 at first and second follow-up respectively). Inter-criterion agreement was moderate to substantial (r = 0.41-0.65 and r = 0.54-0.60 at first and second follow-up) for mRECIST-qEASL. LIRADS TR correlated well with qEASL for all readers at both follow-ups (K = 0.45-0.78; K = 0.39-0.77 for first and second follow-up). qEASL was the most accurate in predicting Tumor-Free Survival (TFS) on first (HR 2.23 [1.44-3.46], p < 0.001) and second (HR 1.69 [1.15-2.48], p = 0.008) follow-up. LIRADS TR was the most accurate in predicting histopathological necrosis (8 patients underwent liver transplantation and 1 patient underwent tumor resection during the period of the study). CONCLUSIONS:HCC response assessment following TARE is challenging, resulting in poor to moderate inter-reader agreement for mRECIST, and moderate inter-reader agreement for LIRADS TR response assessment criteria. qEASL outperformed mRECIST criteria for early identification of responders and predicting TFS, suggesting an advantage in volumetric tumor response assessment. LIRADS TR outperformed other criteria in predicting pathological necrosis.

PURPOSE/OBJECTIVE:To evaluate the effect of English proficiency on abdominal MRI imaging quality. METHODS:Three equal-sized cohorts of patients undergoing 3T abdominal MRI were identified based on English proficiency as documented in the EMR: Primary language of English; English as a second language (ESL)/no translator needed; or ESL, translator needed (42 patients per cohort for total study size of 126 patients). Three radiologists independently used a 1-5 Likert scale to assess respiratory motion and image quality on turbo spin-echo T2WI and post-contrast T1WI. Groups were compared using Kruskal-Wallis tests. RESULTS:For T2WI respiratory motion, all three readers scored the Translator group significantly worse than the English and ESL/no-Translator groups (mean scores across readers of 2.98 vs. 3.58 and 3.51; p values < 0.001-0.008). For T2WI overall image quality, all three readers also scored the Translator group significantly worse than the English and ESL/no-Translator groups (2.77 vs. 3.28 and 3.31; p values 0.002-0.005). For T1WI respiratory motion, mean scores were not significantly different between groups (English: 4.14, ESL/no-Translator: 4.02, Translator: 3.94; p values 0.398-0.597). For T1WI overall image quality, mean scores also were not significantly different (4.09, 3.99, and 3.95, respectively; p values 0.369-0.831). CONCLUSION/CONCLUSIONS:Abdominal MR examinations show significantly worse T2WI respiratory motion and overall image quality when requiring a translator, even compared with non-translator exams in non-English primary language patients. Strategies are warranted to improve coordination among MR technologists, translators, and non-English speaking patients undergoing abdominal MR, to ensure robust image quality in this vulnerable patient population.

Endometriosis is a common gynecologic disorder characterized by the presence of ectopic endometrial tissue outside the endometrial cavity. Magnetic Resonance Imaging (MRI) has become a mainstay for diagnosis and staging of this disease. In the literature, significant heterogeneity exists in the descriptions of imaging findings and anatomic sites of involvement. The Society of Abdominal Radiology's Endometriosis Disease-Focused Panel presents this consensus document to establish an MRI lexicon for endometriosis MRI evaluation and anatomic localization.

Endometriosis is a common entity causing chronic pain and infertility in women. The gold standard method for diagnosis is diagnostic laparoscopy, which is invasive and costly. MRI has shown promise in its ability to diagnose endometriosis and its efficacy for preoperative planning. The Society of Abdominal Radiology established a Disease-Focused Panel (DFP) to improve patient care for patients with endometriosis. In this article, the DFP performs a literature review and uses its own experience to provide technical recommendations on optimizing MRI Pelvis for the evaluation of endometriosis.

PURPOSE/OBJECTIVE:To survey Society of Abdominal Radiology Crohn's Disease (CD) Disease-Focused Panel (DFP) members to understand state-of-the-art CT/MR enterography (CTE/MRE) protocols and variability between institutions. METHODS:This study was determined by an institutional review board to be "exempt" research. The survey consisted of 70 questions about CTE/MRE patient preparation, administration of contrast materials, imaging techniques, and other protocol details. The survey was administered to DFP members using SurveyMonkey® (Surveymonkey.com). Descriptive statistical analyses were performed. RESULTS:Responses were received from 16 DFP institutions (3 non-USA, 2 pediatric); 15 (94%) were academic/university-based. 10 (63%) Institutions image most CD patients with MRE; 4 (25%) use CTE and MRE equally. Hypoperistaltic medication is given for MRE at 13 (81%) institutions versus only 2 (13%) institutions for CTE. Most institutions have a technologist or nurse monitor oral contrast material drinking (n = 12 for CTE, 75%; n = 11 for MRE, 69%). 2 (13%) institutions use only dual-energy capable scanners for CTE, while 9 (56%) use either a single-energy or dual-energy scanner based on availability. Axial CTE images are reconstructed at 2-3 mm thickness at 8 (50%) institutions, > 3 mm at 5 (31%), and < 2 mm at 3 (19%) institutions. 13 (81%) institutions perform MRE on either 1.5 or 3T scanners without preference. All institutions perform MRE multiphase postcontrast imaging (median = 4 phases), ranging from 20 to 600 s after contrast material injection. CONCLUSION/CONCLUSIONS:CTE and MRE protocol knowledge from DFP institutions can help radiology practices optimize/standardize protocols, potentially improving image quality and patient outcomes, permitting objective comparisons between examinations, and facilitating research.

Representatives from the Society of Abdominal Radiology Crohn's Disease-Focused Panel, the Society for Pediatric Radiology, the American Gastroenterological Association, and other international experts recently reported consensus recommendations for standardized nomenclature for the interpretation and reporting of CT enterography and MR enterography findings of small bowel Crohn disease. The consensus recommendations included CT enterography and MR enterography bowel wall findings that are associated with Crohn disease, findings that occur with penetrating Crohn disease, and changes that occur in the mesentery related to Crohn disease. Also included were recommended radiology report impression statements that summarize the findings of small bowel Crohn disease at CT enterography and MR enterography. This article, authored by the Society of Abdominal Radiology Crohn's Disease-Focused Panel, illustrates the imaging findings and recommended radiology report impression statements described in the consensus recommendations with examples of CT enterography and MR enterography images. Additional interpretation guidelines for reporting CT enterography and MR enterography examinations are also presented. The recommended standardized nomenclature can be used to generate radiology report dictations that will help guide medical and surgical management for patients with small bowel Crohn disease. Online supplemental material is available for this article.^©RSNA, 2020.

PURPOSE/OBJECTIVE:To propose a highly accelerated, high-resolution dynamic contrast-enhanced MRI (DCE-MRI) technique called GRASP-Pro (golden-angle radial sparse parallel imaging with imProved performance) through a joint sparsity and self-calibrating subspace constraint with automated selection of contrast phases. METHODS:GRASP-Pro reconstruction enforces a combination of an explicit low-rank subspace-constraint and a temporal sparsity constraint. The temporal basis used to construct the subspace is learned from an intermediate reconstruction step using the low-resolution portion of radial k-space, which eliminates the need for generating the basis using auxiliary data or a physical signal model. A convolutional neural network was trained to generate the contrast enhancement curve in the artery, from which clinically relevant contrast phases are automatically selected for evaluation. The performance of GRASP-Pro was demonstrated for high spatiotemporal resolution DCE-MRI of the prostate and was compared against standard GRASP in terms of overall image quality, image sharpness, and residual streaks and/or noise level. RESULTS:Compared to GRASP, GRASP-Pro reconstructed dynamic images with enhanced sharpness, less residual streaks and/or noise, and finer delineation of the prostate without prolonging reconstruction time. The image quality improvement reached statistical significance (P < 0.05) in all the assessment categories. The neural network successfully generated contrast enhancement curves in the artery, and corresponding peak enhancement indexes correlated well with that from the manual selection. CONCLUSION/CONCLUSIONS:GRASP-Pro is a promising method for rapid and continuous DCE-MRI. It enables superior reconstruction performance over standard GRASP and allows reliable generation of artery enhancement curve to guide the selection of desired contrast phases for improving the efficiency of GRASP MRI workflow.

BACKGROUND:Evaluation of prostate MRI relies on diffusion-weighted imaging (DWI), commonly distorted by susceptibility artifacts, thereby creating a need for approaches to correct such distortion. PURPOSE/OBJECTIVE:To compare geometric distortion on prostate MRI between standard DWI and a geometric distortion correction method for DWI described as static distortion correction DWI (SDC DWI). STUDY TYPE/METHODS:Retrospective case study. POPULATION/METHODS:Thirty patients (ages 31-81 years) undergoing prostate MRI. SEQUENCE/UNASSIGNED:-field map to estimate geometric distortions. ASSESSMENT/RESULTS:WI) as an anatomic standard. Pixel shifts and apparent diffusion coefficient (ADC) values were compared between prostate contours applied to the SDC DWI and standard DWI sequences. Detailed characterization of the impact of SDC DWI was performed in three representative patients. STATISTICAL TESTS/UNASSIGNED:One-way analysis of variance (ANOVA) test, Spearman correlation test, and Bland-Altman plots were calculated. RESULTS:= 0.21). DATA CONCLUSION/UNASSIGNED:SDC DWI appears to correct for susceptibility-related pixel shifts in the prostate compared with standard DWI, which may have value for assessing prostate lesions obscured by geometric warping. Level of Evidence 4 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2019.

BACKGROUND:Quantifying the biomechanical properties of pancreatic tumors could potentially help with assessment of tumor aggressiveness, prognosis, and prediction of therapy response. PURPOSE/OBJECTIVE:To quantify respiratory-induced deformation in the pancreas and pancreatic lesions using XD-GRASP (eXtra-Dimensional Golden-angle RAdial Sparse Parallel), MRI. STUDY TYPE/METHODS:W) imaging were studied. SUBJECTS/METHODS:Thirty-two patients (12 male and 20 female) including nine with pancreatic lesions constituted our study cohort. FIELD STRENGTH/SEQUENCE/UNASSIGNED:WI contrast-enhanced gradient echo radial free-breathing acquisition. ASSESSMENT/RESULTS:Using the XD-GRASP imaging technique, the acquired free-breathing radial data were sorted and binned into 10 consecutive respiratory motion states that were jointly reconstructed. 3D deformation fields along the respiratory dimension were computed using an optical flow method and were analyzed in the pancreas. STATISTICAL TESTS/UNASSIGNED:The Wilcoxon signed-rank test was used to assess the difference in average displacement across pancreatic regions, while the Wilcoxon rank-sum test was used for displacement differences between patients with and without tumors. The interclass correlation coefficient (ICC) was computed to assess consistency between observers for each image quality measure. RESULTS:There was a significantly larger displacement in the pancreatic tail compared with the head (8.2 ± 3.7 mm > 5.8 ± 2.4 mm; P < 0.001) and body regions (8.2 ± 3.7 mm > 6.6 ± 2.9 mm; P < 0.001). Furthermore, there was reduced normalized average displacement in patients with pancreatic lesions compared with subjects without lesions (0.33 ± 0.1 < 0.69 ± 0.26, P < 0.001 for the head; 0.30 ± 0.1 < 0.84 ± 0.31, P < 0.001 for the body; and 0.44 ± 0.31 < 1.08 ± 0.53, P < 0.001 for the tail, respectively). DATA CONCLUSION/UNASSIGNED:Free-breathing respiratory motion-sorted XD-GRASP MRI has the potential to noninvasively characterize the biomechanical properties of the pancreas by quantifying breathing-induced mechanical displacement. LEVEL OF EVIDENCE/METHODS:4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019.