Transabdominal ultrasound for standardized measurement of bowel wall thickness in normal children and those with Crohn's disease.

BACKGROUND The intestinal wall can be visualized using high resolution transabdominal ultrasound (TUS). TTUS measurement of the bowel wall thickness has been described in adults but data are lacking in children. The purpose of this prospective study was to sonographically investigate bowel wall thickness in healthy children and children with Crohn's disease. MATERIAL AND METHODS TUS (5-15 MHz) of the intestine was performed in 58 healthy children (age range 3 to 16 years) and in 30 children with Crohn's disease (age range 8 to 17 years). The following regions were assessed and bowel wall thickness measured: terminal ileum, cecum, right flexure, and sigmoid colon. In patients with Crohn's disease, the involved region was additionally assessed regarding length of involved segment and sonographic signs of transmural inflammation and fistula. RESULTS TUS allowed adequate measurement of bowel wall thickness in all 58 healthy children (100%) and in all 30 Crohn's disease patients (100%). The bowel wall thickness significantly differed between groups. Bowel wall thickness (mean +/- SD) in all segments was less then 2 mm in all healthy children (1.0+/-0.1 mm terminal ileum, 1.1+/-0.1 mm cecum, 1.1+/-0.1 mm right flexure, and 1.3+/-0.1 mm sigmoid colon). In Crohn's disease patients, bowel wall thickness was ≥ 3 mm in the ileocecal region and was significantly increased (5.1+/-1.9 mm) compared to the healthy children. The mean length of involved segment was 15+/-6.5 cm [5 - 30 cm]. Additional findings in Crohn's disease patients were: transmural inflamation (3/30), interenteric fistula (3/30), gastrocolic fistula (1/30) and vesicoenteric fistula (1/30). CONCLUSIONS Similar to adults, normal bowel wall thickness in children is always less than 2 mm. In all patients with Crohn's disease, increased bowel wall thickness could be detected. TUS is a helpful tool in the diagnosis and assessment of activity and complications in Crohn's disease.