Determining the site and causes of colonic obstruction with sonography.

Abstract

We studied the value of sonography in determining the site and cause of colonic obstruction. Sonographic findings in 26 patients with known (n = 21) or suspected (n = 5) colonic obstruction on the basis of clinical findings and abdominal radiographs were correlated with radiologic and surgical findings. Colonic obstruction was proved in all with findings from surgery (n = 18) or from barium enema and CT (n = 8). Causes of the obstructions included colorectal cancer (n = 13), ileocolic intussusception (n = 11), transverse colonic adhesion (n = 1), and sigmoid volvulus (n = 1). Sonographic criterion of obstruction was the demonstration of a continuous distension of colonic loop with an abrupt transition to an empty distal colon. The value of sonography in terms of indicating the level and cause of colonic obstruction was evaluated. The location of colonic obstruction was established by using sonography in 22 (85%) of 26 cases, and the cause of obstruction was identified in 21 (81%) cases. Sonography depicted a mass (n = 5) or a segmental wall thickening (n = 5) in cases of colon cancer, and a target or doughnut sign in cases of ileocecal intussusception (n = 11). Sonography failed to depict the cause of obstruction in three cases of colon cancer and one case each of adhesion and sigmoid volvulus. Our experience suggests that sonography is useful for examining patients with colonic obstruction to determine the level and cause of the obstruction.