To evaluate the correlation between Matts' endoscopic grades in ulcerative colitis (UC) and colonic wall structure, we used
a miniature ultrasonic probe system (MUS) to study 51 MUS images obtained from 39 patients with active ulcerative colitis and
22 images from 22 controls. We found, first, that the mucosal (M), submucal (SM), and muscularis propria layers (MP) of
the colonic wall were significantly thicker in patients with ulcerative colitis (1.35±0.52 mm, 1. 48±0.48 mm, and 0.91±0.35
mm, respectively) than they were in the controls (0.52±0.17 mm, 0.83±0.40 mm, and 0.60±0.26 mm, respectively).
Second, when classified using Matts' endoscopic grades in 51 ulcerative colitis lesions, colonic wall thickness in MUS images was
slightly thicker in Matts' grades 3(13 cases)and 4(10 cases) (3.81±0.93 mm and 4.31±1.4 mm, respectively) than in Matts'
grade 2(28 cases; 3.36±0.73 mm). Third, rates of irregularity at the M/SM borderline were higher in Matts' grades 3 and
4 than in Matts' grade 2. No correlation between rate of irregularity at the SM/MP borderline and Matts' endoscopic grade was
found, however. MUS is therefore considered useful in the evaluation, diagnosis , and grading of severity of ulcerative colitis.