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).

Figure 2 Images of HUS corresponding with their histological stage A: A round mass originated from submucosal (SM) layer in the descending colon, its histological stage was SM (T1). B: A round mass with deformed PM layer (T2) in transverse colon, its histological stage was PM (T2). C: A large endoluminal polypoid mass penetrating the wall and extending to pericolic fat layer. HUS judged stage was T3, its histological stage was T3. D: A carcinoma with serosal infiltration extending into pericolic adjacent tissue in descending colon. HUS judged stage was T4, its histological stage was T4.

Figure 3 Images of HUS not corresponding with their histological stage. A: Sigmoid colon cancer; HUS judged as PM cancer (T2), but histology revealed pericolic fat infiltrated by tumor cells (T3). B: Transverse colon cancer; HUS judged as PM cancer (T2), but histology revealed intact PM layer and tumor cells infiltrated only SM layer (T1).