MR enterography radiologic ulcers in newly diagnosed ileal Crohn disease in children: frequency, inter-radiologist agreement, and clinical correlation.

BACKGROUND

Radiologic ulcers are increasingly recognized as an imaging finding of bowel wall active inflammation in Crohn disease (CD).

OBJECTIVE

To determine the frequency of ulcers at MR enterography (MRE) in children with newly diagnosed ileal CD, assess agreement between radiologists, and evaluate if their presence correlates with other imaging and clinical features of intestinal active inflammation.

MATERIALS AND METHODS

This retrospective study included 108 consecutive pediatric patients (ages 6-18 years) with newly diagnosed ileal CD that underwent clinical MRE prior to treatment initiation between January 2021 and December 2022. MRE examinations were independently reviewed by three pediatric radiologists who indicated the presence vs. absence of ulcers, ulcer severity (categorical depth), and ulcer extent (categorical number of ulcers). Maximum bowel wall thickness and length of disease were measured and averaged across readers. Patient demographics and clinical inflammatory markers were documented from electronic health records. Inter-radiologist agreement was assessed using Fleiss' kappa (k) statistics. Student's t-test was used to compare continuous variables.

RESULTS

Mean patient age was 13.9 years (67 [62%] boys). Radiologic ulcers were recorded in 64/108 (59.3%) cases by reader 1, 70/108 (64.8%) cases by reader 2, and 49/108 (45.4%) cases by reader 3 (k = 0.36). Based on majority consensus, radiologic ulcers were present in 60/108 (55.6%) participants. Inter-radiologist agreement for ulcer severity was k = 0.23, while ulcer extent was k = 0.66. There were significant differences in C-reactive protein, erythrocyte sedimentation rate, fecal calprotectin, albumin, maximum bowel wall thickness, and length of disease between patients without and with radiologic ulcers (P < 0.05). The sensitivity and specificity of MRE for detecting endoscopic ulcers were 66.7% (95% CI, 52.1-79.2%) and 69.2% (95% CI, 48.2-85.7%), respectively.

CONCLUSION

Radiologic ulcers are visible in children with newly diagnosed ileal CD, although inter-radiologist agreement is only fair. The presence of ulcers is associated with clinical laboratory inflammatory markers as well as other MRE findings of disease activity and is an additional imaging finding that can be used to evaluate intestinal inflammation.