Yedaun Lee MD, Presenter: Nothing to Disclose

Seong Ho Park MD, Abstract Co-Author: Research Consultant, INFINITT Healthcare Co, Ltd Research Grant, DONGKOOK Pharmaceutical Co, Ltd Research Grant, General Electric Company

Kyung Jo Kim, Abstract Co-Author: Nothing to Disclose

Bo-Kyeong Kang MD, Abstract Co-Author: Nothing to Disclose

So Yeon Kim, Abstract Co-Author: Nothing to Disclose

Seung Soo Lee MD, Abstract Co-Author: Nothing to Disclose

To prospectively determine the performance of diffusion-weighted (DW) MR enterography (MRE) for evaluating bowel inflammation of Crohn’s disease

17 men and 5 women with Crohn’s disease (mean age, 29.5 years) underwent conventional contrast-enhanced (CE) MRE and DW-MRE at b=900 s/mm² on a 3T system and ileocolonoscopy as the reference standard within 1-week interval. For precise location-by-location match between MRE and endoscopy, the terminal ileum, cecum and ascending colon, and rectum were only analyzed. CE-MRE and DW-MRE were reviewed independently blinded to each other except that the bowel segments to evaluate were pre-marked on DW-MRE by a third person given the lack of anatomical details on DW images. Hyperintensity of the bowel wall on DW-MRE comparable to the signal of mesenteric lymph nodes or the spleen (in the absence of lymph nodes); and presence of mural hyperenhancement, stratification, or T2 hyperintensity, perienteric infiltration, or comb sign on CE-MRE were considered positive findings. Endoscopic findings were stratified into 4 groups: normal or healed lesion (i.e. inactive) and three degrees of bowel inflammation including erythema/edema only, aphthoid lesions only, and overt ulcers. The sensitivity and specificity of DW-MRE and CE-MRE were compared.

A total of 64 bowel segments (22 with ulcers, 14 with aphthoid lesions, 2 with erythema/edema, and 26 inactive) were included. DW-MRE sensitivity was 86.4 (19/22), 57.1 (8/14), and 0% (0/2) for ulcers, aphthoid lesions, and erythema/edema, respectively, while the sensitivity of CE-MRE was 90.9 (20/22),14.3 (2/14), and 0% (0/2), respectively, demonstrating no significant difference for ulcers albeit higher sensitivity in DW-MRE for all active lesions (71.1vs. 57.9%). DW-MRE specificity (46.2% [12/26]) was significantly lower compared with CE-MRE (100% [26/26]). False-positive DW-MRE results occurred mostly in the colon (13/14) and was largely associated with undistended bowel (11/14).

DW-MRE was more sensitive than CE-MRE for non-ulcerative active bowel lesions but was less specific for excluding active inflammation, generating a high rate of false positives presumably related to undistended bowel.

DW-MRE sensitively shows the bowel inflammation of Crohn’s disease; however, its propensity for false positivity and the high accuracy of CE-MRE obscures the real clinical benefit of DW-MRE.

Lee, Y, Park, S, Kim, K, Kang, B, Kim, S, Lee, S, Diffusion-weighted MR Enterography for Evaluating Crohn’s Disease Activity: A Blinded Prospective Study of Diagnostic Performance Using Stratified Endoscopic Severity as the Reference Standard.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13016382.html