Role of early ultrasound in detecting inflammatory intestinal disorders and identifying their anatomical location within the bowel

Background: Although bowel ultrasound is a widely accepted diagnostic tool in bowel diseases, its value as the primary imaging procedure in patients with symptoms/signs suggestive of inflammatory bowel disorders is still unclear. Aim: To investigate the accuracy of bowel ultrasound compared with barium X-ray studies, computed tomography, endoscopy and bowel surgery in the initial assessment of inflammatory bowel disorders. Methods: Four hundred and eighty-seven patients hospitalized consecutively for symptoms or signs suggestive of a bowel disorder between December 1999 and March 2002 were initially enrolled in the study. All patients underwent bowel ultrasound as the first imaging procedure within 36 h of admission; radiographic evaluations, endoscopy and/or surgery were then performed as appropriate and the results of these investigations were used as the gold standard. Results: Three hundred and thirty-six patients had pathological findings of the bowel detectable at ultrasound as the final diagnosis. The main organic disorders found were Crohn's disease (56%), ulcerative/indeterminate colitis (30%), bowel tumours (5%), appendicitis/diverticulitis (2%) and other inflammatory conditions (8%). The overall sensitivity and specificity of bowel ultrasound were 85% and 95%, respectively, whereas the positive and negative predictive values were 98% and 75%, respectively. Comparisons of ultrasound with X-ray or endoscopic results by disease localization showed that the diagnostic performance of ultrasound was higher for inflammatory conditions of the ileum and sigmoid/descending colon (sensitivity of 92% and 87%, respectively), whereas abnormalities localized in the rectum, duodenum and proximal jejunum were often missed by ultrasound. Conclusions: In expert hands, bowel ultrasound is highly predictive of inflammatory disease localized in the ileum or colon, and may well be used as the primary imaging method when Crohn's disease or ulcerative colitis is suspected on a clinical basis.