Endorectal sonography.

Endorectal sonography is a technique that has been developed recently to visualize the rectal wall and perirectal tissues with a high degree of clarity. Studies utilizing endorectal sonography in the preoperative staging of rectal carcinoma have reported an accuracy of between 67 and 92% in the visualization of the depth of tumor invasion in the rectal wall. This surpasses the accuracy reported for digital exam and other preoperative imaging methods such as CT and MRI. Perirectal lymphadenopathy is also well visualized by this method and guided biopsy of perirectal nodes has been reported. Precise preoperative staging of rectal carcinoma by endorectal sonography is an important technique that can: (1) improve surgical planning, (2) provide prognosis in nonsurgical candidates, and (3) select patients suitable for local excision therapy.