Purpose or Case Report: Gadolinium deposition in normal tissues is an increasingly recognized consequence of intravenous gadolinium contrast agents. Children with inflammatory bowel disease (IBD) undergo frequent surveillance imaging with contrast enhanced MR enterography (MRE).
Purpose: To determine the benefit (if any) of IV contrast in evaluation of IBD by MRE.
Methods & Materials: This was a retrospective, IRB approved study. The radiology information system was searched to identify all children who had undergone MRE and endoscopy within 6 weeks of each other in 2016. Imaging studies were interpreted by 2 radiologists, blinded to all clinical information, in 2 sessions 6 weeks apart (session 1 pre-contrast MRE; session 2 pre/post contrast MRE). The pre- and pre/post contrast assessment of bowel inflammation was assessed with respect to endoscopy.
A logistic regression model was evaluated using receiver operating characteristics curves and expressed by c-statistics. The concordance of each assessment with endoscopy was compared by the c-statistics using the DeLong method. Agreement between the raters was evaluated using a Cohen’s or the weighted kappa statistics, as appropriate, and 95% confidence interval. A two-sided P-value < 0.05 was considered statistically significant. Descriptive statistics were used for assessment of IBD complications, with pre/post MRE as the reference standard.
Results: 52 children (46% female), mean age 13.2 (SD 3.42) years formed the study cohort. 77% (40/52) had evidence of inflammation on endoscopic biopsy. Pre/post contrast MRE showed no significant increase in the c-statistics compared to pre contrast MRE (Table 1). Intravenous contrast showed no significant change in interobserver agreement for assessment of inflammation in either the small (kappa 0.92 pre MRE, 0.88 pre/post MRE) or large bowel (kappa 0.83 pre MRE, 0.73 pre/post MRE). IV contrast had no significant impact on interobserver agreement for length of small bowel inflamed (kappa 0.90 pre MRE, 0.95 pre/post MRE). Assessment of IBD complications was improved with IV contrast, with 3/5 cases with perianal penetrating disease not recognised on pre MRE.
Conclusions: Routine administration of IV gadolinium has no impact on assessment of small or large bowel inflammation. However, there is potential for missing perianal penetrating disease using a non contrast protocol.