Evaluation of intestinal ultrasound for disease activity assessment in patients with inflammatory bowel disease: A cross-sectional study at a tertiary centre in Malaysia

Abstract

Background: The use of intestinal ultrasound (IUS) in the management of inflammatory bowel disease (IBD) is emerging. We aim to determine the performance of IUS in the assessment of disease activity in IBD.

Methods: This is a prospective cross-sectional study of IUS performed on IBD patients in a tertiary centre. IUS parameters including intestinal wall thickness, loss of wall stratification, mesenteric fibrofatty proliferation, and increased vascularity were compared with endoscopic and clinical activity indices.

Results: Among the 51 patients, 58.8% were male, with a mean age of 41 years. Fifty-seven percent had underlying ulcerative colitis with mean disease duration of 8.4 years. Against ileocolonoscopy, IUS had a sensitivity of 67% (95% confidence interval (CI): 41-86) for detecting endoscopically active disease. It had high specificity of 97% (95% CI: 82-99) with positive and negative predictive values of 92% and 84%, respectively. Against clinical activity index, IUS had a sensitivity of 70% (95% CI: 35-92) and specificity of 85% (95% CI: 70-94) for detecting moderate to severe disease. Among individual IUS parameters, presence of bowel wall thickening (>3 mm) had the highest sensitivity (72%) for detecting endoscopically active disease. For per-bowel segment analysis, IUS (bowel wall thickening) was able to achieve 100% sensitivity and 95% specificity when examining the transverse colon.

Conclusions: IUS has moderate sensitivity with excellent specificity in detecting active disease in IBD. IUS is most sensitive in detecting a disease at transverse colon. IUS can be employed as an adjunct in the assessment of IBD.

Keywords: Clinical activity index; endoscopic activity index; ileocolonoscopy; inflammatory bowel disease; intestinal ultrasound.

Figure 1

Intestinal ultrasound images show (a) thickened bowel wall with loss of bowel wall stratification (white arrow) with (b) increased bowel wall vascularity, (c) enlarged lymph node (black arrow) and increased mesenteric echogenicity indicating mesenteric fibrofatty proliferation (star) as well as (d) narrowing or stenosis of the bowel lumen (white arrow) with mild thickened bowel

Figure 2

False negative case example of a 43-year-old with history of Ulcerative Colitis (UC) shows (a) increased fat thickness but no mesenteric echogenicity with normal bowel wall thickness that measures 3 mm at transverse colon. (b) IUS images at descending colon shows mild thickened bowel (at upper limit of normal thickness) with no loss of stratification; thus, concluded as no active disease on ultrasound (c) Axial CT abdomen taken a day after shows mild thickened bowel wall of the transverse colon as well as collapsed and mildly thickened descending colon (white arrows in d). There is mild mesenteric fat streakiness. This patient had clinically active disease of UC at the time of imaging