title: Assessment of Activity of Crohn Disease by Diffusion-Weighted Magnetic Resonance Imaging.
abstract: To assess the diagnostic efficacy of diffusion-weighted MR imaging (DWI) for evaluating inflammatory activity in patients with Crohn's disease (CD). A total of 47 CD patients underwent MR enterography (MRE) and DWI using 3 b values of 50, 400, and 800 s/mm. Apparent diffusion coefficients (ADCs) of inflamed and normal bowel wall were calculated. The conventional MRE findings and DWI signal intensities were qualitatively scored from 0 to 3. The correlation between Crohn disease activity index (CDAI) and both ADCs and magnetic resonance imaging scores was analyzed. Receiver-operating characteristic curve analysis was used to determine the diagnostic accuracy of CD activity. Of the 47 patients, 25 were active CD (CDAI≥150) and 22 were inactive (CDAI<150). Diffusion-weighted MR imaging and MRE + DWI scores of active CD were significantly higher than that of inactive CD (both P < 0.001). Apparent diffusion coefficients in inflamed segments of active CD were lower than that of inactive CD (P < 0.001). The DWI scores (r = 0.74, P < 0.001), ADCs (r = -0.71, P < 0.001), MRE scores (r = 0.54, P < 0.001), and MRE + DWI scores (r = 0.66, P < 0.001) were all correlated with CDAI. The areas under the receiver-operating characteristics curves for ADCs, DWI scores, MRE scores, and MRE + DWI scores ranged from 0.83 to 0.98. The threshold ADC value of 1.17 × 10 mm/s allowed differentiation of active from inactive CD with 100% sensitivity and 88% specificity. Diffusion-weighted MR imaging and ADC correlated with CD activity, and had excellent diagnostic accuracy for differentiating active from inactive CD.
authors.affiliation: From the Department of Radiology, (X-HL, C-HS, X-SJ, Z-PL); Department of Gastroenterology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China (RM, M-HC); Department of Radiology, UT Southwestern Medical Center, Dallas, TX (Z-WZ); and Department of Radiology, Conde de S. Januario Central Hospital, Macau, China (MHP).
authors.forename: Xue-Hua
authors.initials: XH
authors.lastname: Li
authors.forename: Can-Hui
authors.initials: CH
authors.lastname: Sun
authors.forename: Ren
authors.initials: R
authors.lastname: Mao
authors.forename: Zhong-Wei
authors.initials: ZW
authors.lastname: Zhang
authors.forename: Xiao-Song
authors.initials: XS
authors.lastname: Jiang
authors.forename: Margaret H
authors.initials: MH
authors.lastname: Pui
authors.forename: Min-Hu
authors.initials: MH
authors.lastname: Chen
authors.forename: Zi-Ping
authors.initials: ZP
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003106:Colon / Q000473:pathology*; D003424:Crohn Disease / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007082:Ileum / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D055815:Young Adult