OBJECTIVE. The purpose of this study was to evaluate four previously validated MRI activity scoring systems for diagnosis and grading of Crohn disease (CD) in the terminal ileum against an endoscopic and histopathologic reference standard. SUBJECTS AND METHODS. Ethics approval and written informed consent were obtained. Subjects with known or suspected CD were prospectively recruited between December 2011 and August 2014. Each patient underwent MRI and ileocolonoscopy with terminal ileum biopsies. Four MRI scoring systems (Magnetic Resonance Index of Activity [MaRIA], Clermont score, London score, and Crohn disease MRI Index) and component features were applied by two observers and correlated to the Crohn disease endoscopic index of severity (CDEIS, 0-44) and histopathologic endoscopic acute inflammation score (0-6). Interobserver agreement (weighted kappa and intraclass correlation coefficient [ICC]) and diagnostic accuracy for active and ulcerating endoscopic or histopathologic disease were evaluated. RESULTS. Ninety-eight patients (median age, 32 years old; 55 women, 43 men) were included. All four scoring systems showed good interobserver agreement (ICC = 0.70-0.78), moderate-to-strong correlation to CDEIS (r = 0.57-0.67) and weak-to-moderate correlation to endoscopic acute inflammation score (r = 0.38-0.49). Scoring systems' diagnostic accuracy for active and ulcerating endoscopic disease ranged from 73% to 78% and 71% to 76%, respectively, whereas for active histopathologic disease accuracy ranged from 65% to 72%. Between the scoring systems, no significant differences were found for both observers regarding interobserver agreement, correlation coefficients, and diagnostic accuracy. CONCLUSION. All scoring systems were comparable in terms of interobserver agreement, correlation to the endoscopic and histopathologic reference standard, and diagnostic accuracy. The London score, MaRIA, and Clermont score have the additional benefit of having validated cutoff values for both active and ulcerating endoscopic disease.

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Purpose: The purpose of the study was to compare the performance of contrast-enhanced (CE)-MRI and diffusion-weighted imaging (DW)-MRI in grading Crohn’s disease activity of the terminal ileum. Methods: Three readers evaluated CE-MRI, DW-MRI, and their combinations (CE/DW-MRI and DW/CE-MRI, depending on which protocol was used at the start of evaluation). Disease severity grading scores were correlated to the Crohn’s Disease Endoscopic Index of Severity (CDEIS). Diagnostic accuracy, severity grading, and levels of confidence were compared between imaging protocols and interobserver agreement was calculated. Results: Sixty-one patients were included (30 female, median age 36). Diagnostic accuracy for active disease for CE-MRI, DW-MRI, CE/DW-MRI, and DW/CE-MRI ranged between 0.82 and 0.85, 0.75 and 0.83, 0.79 and 0.84, and 0.74 and 0.82, respectively. Severity grading correlation to CDEIS ranged between 0.70 and 0.74, 0.66 and 0.70, 0.69 and 0.75, and 0.67 and 0.74, respectively. For each reader, CE-MRI values were consistently higher than DW-MRI, albeit not significantly. Confidence levels for all readers were significantly higher for CE-MRI compared to DW-MRI (P < 0.001). Further increased confidence was seen when using combined imaging protocols. Conclusions: There was no significant difference of CE-MRI and DW-MRI in determining disease activity, but the higher confidence levels may favor CE-MRI. DW-MRI is a good alternative in cases with relative contraindications for the use of intravenous contrast medium.

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Rationale and Objectives: The objective of this study was to develop and validate a predictive magnetic resonance imaging (MRI) activity score for ileocolonic Crohn disease activity based on both subjective and semiautomatic MRI features. Materials and Methods: An MRI activity score (the “virtual gastrointestinal tract [VIGOR]” score) was developed from 27 validated magnetic resonance enterography datasets, including subjective radiologist observation of mural T2 signal and semiautomatic measurements of bowel wall thickness, excess volume, and dynamic contrast enhancement (initial slope of increase). A second subjective score was developed based on only radiologist observations. For validation, two observers applied both scores and three existing scores to a prospective dataset of 106 patients (59 women, median age 33) with known Crohn disease, using the endoscopic Crohn's Disease Endoscopic Index of Severity (CDEIS) as a reference standard. Results: The VIGOR score (17.1 × initial slope of increase + 0.2 × excess volume + 2.3 × mural T2) and other activity scores all had comparable correlation to the CDEIS scores (observer 1: r = 0.58 and 0.59, and observer 2: r = 0.34–0.40 and 0.43–0.51, respectively). The VIGOR score, however, improved interobserver agreement compared to the other activity scores (intraclass correlation coefficient = 0.81 vs 0.44–0.59). A diagnostic accuracy of 80%–81% was seen for the VIGOR score, similar to the other scores. Conclusions: The VIGOR score achieves comparable accuracy to conventional MRI activity scores, but with significantly improved reproducibility, favoring its use for disease monitoring and therapy evaluation.

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PURPOSE: To investigate the sensitivity and specificity of polyp detection and the image quality of computed tomographic (CT) colonography at different radiation dose levels and to study effective doses reported in literature on CT colonography. MATERIALS AND METHODS: CT colonography and colonoscopy were performed with 100 mAs in 50 consecutive patients at high risk for colorectal cancer; 50- and 30-mAs CT colonographic examinations were simulated with controlled addition of noise to raw transmission measurements. One radiologist randomly evaluated all original and simulated images for the presence of polyps and scored image quality. Differences in image quality were assessed with the Wilcoxon rank test. Scan protocols from the literature and recent (unpublished) updates were collected. RESULTS: In nine of 10 patients with polyps 5 mm in diameter or larger (sensitivity, 90%) and in seven of 17 patients with polyps smaller than 5 mm, polyps were correctly identified with CT colonography at all dose levels. Specificity for patients without polyps 5 mm or larger was 53%¿60% at all dose levels and for patients without any polyps was 26% (at 100 and 50 mAs) and 48% (at 30 mAs). Image quality decreased significantly as the dose level decreased. The median effective doses (supine and prone positions) calculated from protocols reported in the literature and updates were 7.8 and 8.8 mSv, respectively. CONCLUSION: Although image quality decreases significantly at 30 mAs (3.6 mSv), polyp detection remains unimpaired. The median dose for CT colonography at institutions that perform CT colonographic research is currently 8.8 mSv. Index terms: Colon neoplasms, CT, Colonoscopy@en