Evaluation of echographic diagnosis of rectal cancer using intrarectal ultrasonic examination.
Ultrasonic examinations conducted in order to diagnose the depth of invasion and local lymph node metastases of rectal cancer. The intrarectal approach was performed preoperatively in 99 patients with rectal cancer, using either an Olympus-Aloka ultrasonic endoscopeTM (7.5 MHz) or other probes (Aloka, 7.5 MHz, 5 MHz). Through this method, intrapelvic organs were detected clearly, and hypoechoic findings due to tumors were detected in all patients. The normal rectal wall was echogenically divided into five layers, the third layer being the submucosal and the fourth layer being the proper muscle layer. In some cases, the proper muscle layer was divided into three layers in the echogram. In 79 of 88 patients, the diagnosis of depth of invasion, classified into three groups, was possible. Metastatic lymph nodes were shown as a hypoechoic round mass. In 52 of 71 patients proven to have local lymph node metastases in surgical specimens, lymph node metastases were diagnosed preoperatively. Thus, intrarectal ultrasonography provides valuable information concerning the choice of operating methods for rectal cancer.