[Preoperative clinical evaluations of rectal cancer using rectal echo, X-ray CT and MR-CT]

In order to evaluate the depth of invasion and to determine the stage of rectal cancer, we have recently performed intra-rectal echo, X-ray CT and MR-CT preoperatively. Conventional approaches such as barium enema X-ray and colonofiberscope are not satisfactory to determine the depth of invasion of tumor and to detect adjacent metastatic lymphnodes. Intra-rectal echo can reveal rectal wall layers fairly well, which can be divided into five layers. Using this technique, we are able to determine the depth of invasion of rectal cancer. X-ray CT can demonstrate all the intra-pelvic organs and metastatic lymphnodes surrounding rectal tumor. Invasion to the neighboring organs such as urinary bladder, prostate, seminal vesicle and uterus can also be evaluated preoperatively. MR-CT is also helpful to determine the stage of rectal cancer before operations. Though the images of MR-CT are not so sharp, multi-directional slices of X-ray photographs can be taken by MR-CT and so furthermore evaluations of rectal tumor invasion and adjacent metastatic lymphnodes are possible. In addition, IR-image of MR-CT demonstrates the tumor site dramatically. In conclusion, using these three techniques we can evaluate preoperative clinical stages of rectal cancer and the best operative method can be determined preoperatively.