Value of endoscopic ultrasound in prediction of dysplasia in ulcerative colitis

Ulcerative colitis (UC) is one of the most common forms of chronic inflammatory bowel disease. Its diagnosis is based on history, clinical, radiological, laboratory, endoscopic, and histological examinations. Endoscopic ultrasound (EUS) is a highly accurate diagnostic endoscopic and radiological modality for assessing of rectal pathology. However, EUS data remain scarce for patients with UC. The aim of this study was to assess the correlation between EUS indices and clinical, endoscopic, and histological scores of inflammation in UC and to evaluate the usefulness of EUS in assessing the activity and dysplasia of UC. A total of 57 patients with UC were cross-sectionally evaluated based on clinical (Truelove score), laboratory [complete blood count (CBC), c reactive protein (CRP), erythrocte sedementaion rate (ESR), and fecal calprotectin], and endoscopic (Mayo score) parameters. The patients were divided into three groups: mild UC, moderate UC, and severe UC. They were subjected to EUS at 10, 20, and 30cm from the anal verge to assess the correlation between severity of UC and histopathological examination results. Total wall thickness (TWT) at 10cm from the anal verge was positively and highly significantly correlated to histopathological severity in comparison with 20 and 30 cm from anal verge (P=0.001). TWT at 10 cm by EUS was a significant predictor of the histopathological severity of UC (P=0.007). For TWT of the colon at 10 cm from the anal verge, significant discrimination (P=0.02) between severe UC and mild to moderate UC could be achieved by utilizing a cutoff of 3.5 mm with sensitivity of 60.5% and specificity of 85.7%. In addition, highly significant (P=0.006) discrimination of mucosal dysplasia in UC could be achieved using TWT cutoff of 5.05mm at 10cm from the anus with sensitivity of 75% and specificity of 94.3%. For EUS at 10cm from the anal verge, TWT cutoff of 3.5mm can assess histopathological severity of UC, and TWT cutoff of 5.05 mm can predict dysplasia in UC.