Nieun Seo MD, Presenter: Nothing to Disclose

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

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

Yedaun Lee MD, Abstract Co-Author: Nothing to Disclose

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

Hyun Kwon Ha MD, Abstract Co-Author: Nothing to Disclose

To prospectively determine whether MR enterography (MRE) performed with diffusion-weighted imaging (DWI) and without intravenous contrast is diagnostically noninferior to conventional contrast-enhanced (CE) MRE for evaluating Crohn’s disease (CD).

Fifty adults suspicious of CD prospectively underwent clinical assessment, MRE, and ileocolonoscopy within 1 week and 44 patients finally diagnosed with CD (M:F, 34:10; 26.9±6.1 years) were analyzed. Conventional CE-MRE and DWI at b=900 s/mm² were performed. Unenhanced DWI-MRE (i.e. T2-weighted sequences + DWI) and CE-MRE (i.e. T2-weighted sequences + dynamic CE T1-weighted sequences) were reviewed in separate sessions with proper blinding, a washout period, and randomization. A total of 172 small bowel segments representing the entire spectrum from normalcy to severe inflammation in CD as seen on CE-MRE were chosen for the review. The primary endpoint was the proportional agreement between two MRE methods in diagnosing active bowel inflammation, with the noninferiority margin of 85% of agreement. Secondary analyses were performed about the agreement in interpreting penetrating diseases and regarding the MRE accuracy in the terminal ileum for diagnosing all severities of inflammation and for deep ulcers using the endoscopic findings as the reference standard.

The agreement between unenhanced DWI-MRE and CE-MRE in interpreting active bowel inflammation was 92.4% (159/172; one-sided 95% CI, >88.4%). Therefore, the noninferiority of DWI-MRE to CE-MRE was established. Of 8 segments with penetrating diseases shown on CE-MRE, DWI-MRE interpreted 6 segments concordantly, characterized 1 abscess discordantly as phlegmon, and neglected 1 sinus tract. In the 41 terminal ilea with endoscopic reference standard, unenhanced DWI-MRE and CE-MRE did not reveal significant differences in the sensitivity for diagnosing all severities of inflammation (94% [32/34] vs. 97% [33/34]; P=1) or for diagnosing deep ulcers (95% [20/21] for both; P=1).   

DWI-MRE was noninferior to CE-MRE in diagnosing bowel inflammation but showed more considerable discordance with CE-MRE in diagnosing penetrating diseases.

DWI-MRE may substitute CE-MRE for evaluating bowel inflammation in CD patients who are contraindicated for the use of intravenous contrast and are not suspicious of having penetrating diseases. 

Seo, N, Park, S, Kim, K, Lee, Y, Kang, B, Ha, H, MR Enterography with Diffusion-weighted Imaging to Substitute Intravenous Contrast for Evaluating Crohn’s Disease: A Noninferiority Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007973.html