Echoendoscopic characterization of the human colon

PURPOSE: To characterize colon and rectum walls, pericolic and perirectal spaces, using endoscopic ultrasonography miniprobes. METHODS: Sixty individuals (50% males), aged 18-80, were included. Using 12 and 20 MHz endoscopic ultrasonography miniprobes, all different colon segments (ascending, transverse, descending, sigmoid) and rectum were evaluated according to the number and thickness of the different layers in intestinal wall, to the presence and (largest) diameter of vessels in the submucosa and of peri-intestinal nodes. RESULTS: The 20 MHz miniprobe identified a higher number of layers than the 12 MHz miniprobe, with medians of 7 and 5 respectively (p < 0.001). The rectal wall (p = 0.001), its muscularis propria (p < 0.001) and mucosa (p = 0.01) were significantly thicker than the different segments of the colon, which had no significant differences between them. Patients aged 41-60 presented thicker colonic wall and muscularis propria in descending (p = 0.001 and p = 0.004) and rectum (p = 0.01 and p = 0.01). Submucosal vessels were identified in 30% of individuals in descending and rectum, and in 12% in ascending. Adenopathies were observed in 9% of the colon segments and 5% in rectum. CONCLUSIONS: A higher frequency enabled the identification of a higher number of layers. Rectal wall is thicker than the one from all the segments of the colon and there are no differences between these, namely in the ascending colon. Moreover, periintestinal adenopathies were rarely identified but present in asymptomatic individuals. All together, these results describe for the first time features which are relevant during staging and therapeutic management of colonic lesions.