Intestinal Ultrasound to Assess Ulcerative Colitis Disease Activity in Children: External Validation and Comparison of 2 Intestinal Ultrasound Activity Indices

Abstract

Background: There is currently no consensus on the definition of an abnormal intestinal ultrasound (IUS) for children with ulcerative colitis (UC). This cross-sectional study aimed to externally validate and compare 2 existing IUS indices in children with UC.

Methods: Children undergoing colonoscopy for UC assessment underwent IUS the day before colonoscopy, assessed with the Mayo endoscopic subscore. The UC-IUS index and the Civitelli index were compared with the Mayo endoscopic score in the ascending, transverse, and descending colon. The area under the receiver-operating characteristic curve for detecting a Mayo endoscopic score ≥2 of both scores was compared and sensitivity and specificity were calculated.

Results: A total of 35 UC patients were included (median age 15 years, 39% female). The area under the receiver-operating characteristic curve was higher for the UC-IUS index in the ascending colon (0.82 [95% confidence interval (CI), 0.67-0.97] vs 0.76 [95% CI, 0.59-0.93]; P = .046) and transverse colon (0.88 [95% CI, 0.76-1.00] vs 0.77 [95% CI, 0.60-0.93]; P = .01). In the descending colon, there was no difference (0.84 [95% CI, 0.70-0.99] vs 0.84 [95% CI, 0.70-0.98]). The optimal cutoff for the UC-IUS was <1 point to rule out a Mayo endoscopic score ≥2 (sensitivity: 88%, 100%, and 90% in the ascending, transverse, and descending colon, respectively) and a Mayo endoscopic score ≥2 could be detected using a cutoff of >1 (specificity: 84%, 83%, and 87%, respectively). For the Civitelli index, in our cohort, the optimal cutoff was <1 to rule out a Mayo endoscopic score ≥2 (sensitivity 75%, 65%, and 80%, respectively) and a cutoff >1 to detect a Mayo endoscopic score ≥2 (specificity 89%, 89%, and 93%, respectively).

Conclusions: In this cohort, the UC-IUS index performed better than the Civitelli index. The UC-IUS index had both a high sensitivity and specificity in this cohort, when using 1 point as cutoff for a Mayo endoscopic score ≥2.

Keywords: disease monitoring; intestinal ultrasound; pediatric ulcerative colitis; validation.