Comparison of transabdominal ultrasound with quantitative power Doppler and colonoscopic findings for the evaluation of colonic inflammation in active ulcerative colitis

BACKGROUND Transabdominal ultrasound is a promising technique to evaluate inflammatory bowel disease. Several studies have demonstrated a relationship between ultrasound findings and colonic inflammation. However, the applicability of transabdominal ultrasound in patients with ulcerative colitis (UC) has not been elucidated. The aim of this study was to clarify the relationship between the transabdominal ultrasound findings and endoscopic activity in patients with UC. METHODS Patients with active and underwent transabdominal ultrasound and colonoscopy were enrolled in this retrospective single-center analysis. Blood flow in the bowel wall was evaluated by power Doppler ultrasound. Both the thickness and stratification of the bowel wall were assessed by B-mode ultrasound imaging. The endpoints were the correlations between the ultrasound appearances (i.e., blood flow, thickness, and stratification of the bowel wall) and endoscopic activity (endoscopic Mayo Score). RESULTS There were 34 lesions in 26 patients evaluated. Blood flow and thickness of the bowel wall were positively significantly correlated with the endoscopic Mayo Scores (r=0.43, p=0.011 and r=0.503, p=0.002, respectively). According to the bowel stratification, the endoscopic Mayo Scores were significantly higher in unclear and diminished bowel wall stratifications than in the clear bowel wall stratifications (p<0.001 and p<0.001, respectively). When focusing on the endoscopic Mayo Scores of three lesions, blood flow was lower in ulcer lesions with a diameter of ≥10mm than in those with a diameter of <10mm. CONCLUSION All transabdominal ultrasound findings of bowel blood flow, wall thickness, and wall stratification reflected colonic inflammation.