CT findings in the perirectal area following radiation therapy.

The perirectal computed tomography findings of 26 patients who had received radiation therapy for pelvic malignancies are described. They include a widening of the presacral space, increase in the perirectal fat, thickening of the perirectal fibrous tissue, and visualization of a fibrotic connection between the sacrum and rectum. The etiology of these findings is discussed, as well as the differential diagnosis.