Transrectal US as an adjunct in the diagnosis of rectal and extrarectal tumors.

Transrectal ultrasound (US; also called endosonography) was used to evaluate known or suspected rectal and perirectal masses. Thirty-one patients were examined with commercially available endosonographic probes. Those who obtained and interpreted the sonograms had no knowledge of other diagnostic studies, which included digital rectal and sigmoidoscopic examinations, conventional US, and computed tomography (CT). All but one patient underwent surgical exploration for diagnoses that included rectal cancers, perirectal abscesses, presacral endometriosis, intramural dermoid of the rectum, and intramural venous angioma. Transrectal US was able to image all masses situated within 12 cm of the anus. Malignant infiltration of perirectal fat and perirectal node involvement were detected at least as accurately with US as with CT, suggesting that this technique is a cost-effective, reliable adjunct for staging rectal cancers.