Endoscopic ultrasonography in the evaluation of colon and rectal disease.

Endosonography of the colon has until recently been limited to examination of the rectum. Rigid and flexible instruments are currently available which allow for detailed images of the rectal wall. Comparative studies suggest that endosonography may be more accurate than computed tomography in the preoperative staging of rectal carcinoma. Recently, an ultrasound colonoscope has been developed which allows for visual examination, biopsy, and endosonography throughout the colon. Experience with this technique is limited and its role in the evaluation of colonic disease has not yet been determined. Further comparative trials are needed to more fully define the role of endosonography in the diagnosis of colorectal disease.