Accuracy of Humanitas Ultrasound Criteria in Assessing Disease Activity and Severity in Ulcerative Colitis: A Prospective Study

Background: Colonoscopy [CS] is the standard for assessing disease activity in ulcerative colitis [UC], although invasive and poorly tolerated. Bowel ultrasound [BUS] may be a valid alternative in UC patients; however, the comparative accuracy between BUS and CS is unknown. Methods: Consecutive patients with UC were prospectively assessed by CS and BUS. Colonic wall thickening [CWT > 3 mm], colonic wall flow at power Doppler [CWF], colonic wall pattern [CWP], and presence of lymph nodes evaluated at BUS were compared with CS. The endoscopic activity was assessed according to the Mayo endoscopic sub-score [0-3]. All BUS investigations were performed by two independent gastroenterologists and the kappa statistic for agreement was calculated. Ultrasonography-based criteria (Humanitas Ultrasound Criteria [HUC]) were developed. Results: A total of 53 UC patients [56% with left-sided colitis, 19% with pancolitis] were prospectively enrolled. Of these, 22 patients had mucosal healing [Mayo endoscopic sub-score 0-1] and 31 patients were in endoscopic activity. CWT, CWF, hypoechogenic CWP and the presence of lymph nodes significantly correlated with endoscopic activity [p < 0.05]. CWT [p = 0.01] and CWF [p = 0.09] were independent predictors for endoscopic activity. The HUC developed are: [i] the presence of a CWF and CWT > 3 mm; or [ii] the absence of a CWF and CWT > 4.43 mm. They showed high accuracy for the detection of disease activity [sensitivity 0.71, specificity 1.00]. The interobserver agreement for BUS was excellent [kappa 0.86]. Conclusions: BUS is a non-invasive, easy-to-use tool to manage UC patients in clinical practice. HUC were very accurate in assessing disease activity in UC patients.