Preoperative evaluation of rectal carcinoma invasion using transrectal ultrasonography: preliminary experience of 30 patients.

Transrectal ultrasonography was used to examine and to preoperatively evaluate rectal carcinoma invasion in 30 patients. Satisfactory sonography pictures were obtained in 23 patients. Four stages of tumor invasion were identified in our study. The sensitivity of preoperative evaluation in this study was 91%. In order to verify the correspondence between the ultrasonographic findings and the actual histo-anatomic condition of rectum, 10 resected rectal specimens were studied by in vitro ultrasonography. We conclude that the appearance of the muscularis propria layer of rectum as a homogeneous hypoechogenic band can be stably defined with transrectal ultrasonography and is crucial for accurate evaluation of cancer invasion. Although lymph node enlargement was shown as hypoechogenic nodules on the sonographic pictures, the existence of cancer metastasis could not be differentiated in this study.