Rectal wall thickness measured by ultrasound in chronic inflammatory diseases of the colon.

Rectal wall thickness was measured ultrasonically by means of a 7-MHz transducer. 2 mm in diameter. In eight autopsy cases differences between ultrasonic and slide gauge measurements varied from -0.7 mm to 0.2 mm, with a median of 0.05 mm. Patients studies were carried out in 19 control subjects, showing a median rectal wall thickness of 2.6 mm, in 33 patients with ulcerative colitis with a median wall thickness of 2.8 mm, and in 18 patients with colonic Crohn's disease with a median wall thickness of 3.2 mm. These differences were not statistically significant. Subgroups of ulcerative colitis patients showed increasing wall thickness with increasing clinical activity (p less than 0.02), with increasing proctoscopic changes (p less than 0.01), and with increasing histologic activity (p less than 0.05). Corresponding correlations could not be demonstrated within the group of colonic Crohn's disease. It is concluded that even though the method could not distinguish between patients with ulcerative colitis and Crohn's disease of the colon, further studies concerning application of the measuring principle in gastroenterological endoscopy are indicated.