Intestinal ultrasound as non-invasive method in assessment of ulcerative colitis activity

Background: Intestinal ultrasound (IUS) has become an essential, non-invasive tool for evaluating gastrointestinal involvement in inflammatory bowel disease (IBD), particularly ulcerative colitis (UC). With advancements in ultrasound technology, its diagnostic accuracy has significantly improved. This study aimed to assess UC activity using a novel ultrasound-based activity index, using endoscopic findings as the reference standard. Methods: Fifty patients with confirmed UC were enrolled from the Internal Medicine Department at Benha University Hospital in Egypt. They were categorized into two groups: 25 patients in remission (inactive UC) and 25 with active disease. All participants underwent clinical evaluation, colonoscopy, laboratory investigations, and intestinal ultrasound examination. Results: Bowel wall thickness (BWT) and the UC intestinal ultrasound severity index (UC-IUS) were significantly elevated in active UC patients compared to those in remission (P < 0.001). Disruption of wall layer stratification (P = 0.015) and abnormal haustrations (P = 0.002) were also more prominent in active cases. BWT was a significant predictor of disease severity. For severe UC, a BWT >3 mm yielded an AUC of 0.739 (P = 0.001), with 83.33% sensitivity and 92% negative predictive value (NPV). For moderate UC, a cutoff >2.5 mm showed an AUC of 0.822 (P < 0.001), with 90.91% sensitivity and 95.5% NPV. Conclusions: IUS is a reliable and non-invasive method for assessing disease activity in UC. BWT, in particular, demonstrates strong potential as a marker for disease severity and could guide treatment decisions effectively.