The differentiation between Ulcerative Colitis (UC) and Crohn’s Disease (CD) is an important issue for choosing the appropriate medical approach. Endoscopic Ultrasonography (EUS) has been used to distinguish different layers of the gastrointestinal wall. We performed this study to evaluate the accuracy of EUS compared to colonoscopy.

This is a prospective, single blinded diagnostic accuracy study, on 70 patients (UC, 30 CD and 10 healthy controls). After obtaining informed consent, patients underwent a complete work up and were referred to an endosonographist who was blind to the diagnosis. Thickness of mucosa, submucosa and whole wall (TWT) of mid sigmoid colon were measured.

Our study revealed sensitivity of 100% and specificity of 92.3% for EUS to differentiate UC and CD comparing to standard diagnostic tests. Mean mucosal thickness in patients with UC was significantly greater than patients with CD, while, mean sub-mucosal thickness was significantly greater in patients with CD (P<0.001). The sensitivity and Specificity of mean mucosal thickness for differentiating UC form CD and Controls were 92.3% and 88.6% with Cutoff point of 1.1 mm (p<0.001). Moreover, Sensitivity and Specificity of mean submucosal thickness for differentiating CD from UC and Controls were 100% and 86.1% with Cutoff point of 1.08 mm (P<001).

EUS can be used as an efficient and non-invasive modality with acceptable accuracy vs standard tests to differentiate Crohn’s disease and Ulcerative Colitis. However, its accuracy is highly dependent on the experience of the technician.