[Endorectal ultrasonography]

Endorectal ultrasonography is a diagnostic technique that can provide clear image of the rectal wall and the pararectal tissues. The examination is rapid, well tolerated by the patient and accurate. Indications for this investigation include preoperative staging of rectal tumors, surveillance of rectal cancer, and evaluation of pararectal masses. Endoanal ultrasonography provides an image of the anal sphincter muscles and the perianal tissues. Indications for this examination include the evaluation of incontinence, anal fistulas, anal carcinoma and anal pain. A detailed discussion of the image interpretation follows.