Comparison of hydrocolonic sonograpy accuracy in preoperative staging between colon and rectal cancer

Figure 1 Normal images of five-layered colorectal wall architec-tures at each site. A: Distended rectum by instilling 1 000-2 000 mL warm saline inserted with a balloon catheter, B: rectum, C: sigmoid colon, D: descending colon, E: transverse colon, F: ascending colon. The first hyperechoic layer and the 2^nd hypoechoic lesion were mucosa, the 3^rd hyperechoic layer was submucosa, the 4^th hypoechic lesion was muscularis propria, and the 5^th outer echogenic layer was serosa (from inner to outer of the lumen).