Contrast-Free Imaging Can Spot Postop Crohn's Recurrence

By Reuters Staff

June 28, 2021

NEW YORK (Reuters Health) - For the diagnosis of postoperative recurrence of Crohn's disease (CD) at the anastomotic site, diffusion-weighted magnetic resonance enterography (DW-MRE) is on par with contrast-enhanced (CE) MRE, report radiologists from France.

"DW-MRE may replace CE-MRE for the postoperative evaluation of ileocolonic resection in patients with CD, when intravenous administration of gadolinium-based contrast agents (GBCA) is contraindicated," write Dr. Christine Hoeffel and colleagues with Reims University Hospital in the journal Diagnostic and Interventional Imaging.

"These results need to be confirmed by large and prospective studies but could lead to a restricted use of GBCA administration in patients with CD," they add.

They studied 40 patients (mean age, 38; 21 men) who underwent ileal resection for Crohn's disease.

MRE exams were blindly analyzed independently by one senior and one junior radiologist for the presence of small-bowel postoperative recurrence at the anastomotic site.

During the first reading session, T2-, steady-state- and DW-MRE images were reviewed (DW-MRE, or set 1). One month later, during a second reading session, T2-, steady-state- and CE-MRE images were reviewed (CE-MRE, or set 2). Lastly, all sequences were analyzed altogether (set 3).

Fifteen of the 40 (37.5%) patients had endoscopic postoperative recurrence at the anastomotic site.

Sensitivity for the diagnosis of postoperative recurrence was 73% for the senior radiologist and 67% for the junior radiologist using set 1 and 80% for both readers using set 2.

There was no significant difference in sensitivity between reading set 1 and reading set 2, for either the senior or junior radiologist.

Specificity was 96% for both readers in set 1 and set 2.

The area under the receiver operator characteristic curve (AUC) was 0.93 using set 3 versus 0.89 using set 1 and 0.89 with set 2.

No significant differences in AUC were found between set 1 or 2 and set 3, nor between set 1 and 2, the authors report.

Accuracies were 88% and 85% for DW-MRE for the senior and junior radiologists, respectively; 90% for CE-MRE for both readers; and 93% and 88% for the senior and junior radiologist, respectively, with set 3.

"Our study suggests that MRE using DWI may be an alternative to the classical protocol including CE T1-weighted MRE sequences for the diagnosis of endoscopic postoperative recurrence after surgery for CD, even for a junior radiologist," Dr. Hoeffel and colleagues say.

"Our study also indicates that adding DWI to standard CE-MRE does not significantly increase performances for the detection of CD-related endoscopic recurrence after surgery," they note.

While the performances of DW-MRE may seem "rather disappointing," with a sensitivity of only 67% for the junior reader and 73% for the senior reader, specificities were 96% for both readers, they point out.

"Although it may be difficult to directly compare performances across studies, as the endoscopic definition of recurrence is still a matter of debate, our results compare favorably to those of the literature," they note.

The study had no specific funding and the authors have no relevant disclosures.

SOURCE: Diagnostic and Interventional Imaging, online June 18, 2021