Detection of Crohn's disease by ultrasound.

The target appearance of grey scale ultrasound is thought to be a characteristic sign of gastrointestinal wall thickening. It consists of a strong echogenic center surrounded by a sonolucent rim. In a prospective controlled study, the sensitivity and specificity of the ultrasonic B-scan for Crohn's disease were investigated. Fifty-one patients with Crohn's disease and 124 control subjects were studied. Sensitivity and specificity of the ultrasonic target appearance for Crohn's disease were 76% and 88%, respectively. When additional ultrasonic signs of inflammatory bowel disease were considered, sensitivity and specificity rose to 84% and 91%, respectively. Both colon and ileum were affected in 85% of the true-positive and in 8% of the false-negative targets. The Crohn's disease activity index was 213 +/- 136 in patients with true-positive targets and 167 +/- 118 in patients with false-negative target appearances. Most false-positive target phenomena arose from gastrointestinal tumors. It is concluded that ultrasound is a suitable complementary method for the detection of Crohn's disease.