Sonographic evaluation of inflammatory bowel disease: a prospective, blinded, comparative study

Children with inflammatory bowel disease (IBD) undergo invasive and repeated investigations, including contrast radiology and endoscopy.

To assess transabdominal sonography of the colon and distal ileum compared to colonoscopy and barium radiology in known or suspected IBD.

A prospectively recruited cohort of 44 children (median age 12 years, range 3.5-16.5 years; 24 males) underwent transabdominal sonography prior to colonoscopy (n=33) or barium follow-through (n=25). Diagnoses were: Crohn disease (n=25), ulcerative colitis (n=12), indeterminate colitis (n=1), normal (n=6).

Bowel wall thickness (BWT) and endoscopic severity were compared in 153 colonic segments. No difference was found between normal and mildly affected segments. BWT was less in normal bowel than moderate (P<0.001) or severe (P<0.001) lesions. Where BWT was >2.9 mm, sensitivity for moderate/severe disease was 48%, specificity 93%, positive predictive value 83% (likelihood ratio 7). Barium radiology showed terminal ileum abnormality in ten patients (40%). Where ileal BWT was >2.5 mm, comparative sensitivity was 75%, specificity 92%, positive predictive value 88% (likelihood ratio 9). Superior mesenteric artery Doppler did not correlate with disease severity.

Increased BWT has good positive predictive value for moderate/severe disease in the colon proximal to the rectum (>3 mm), and terminal ileum (>2.5 mm). BWT below this cannot exclude moderate/severe mucosal lesions.