Microvascular studies in human radiation bowel disease.

The microvasculature was investigated in the normal bowel (n = 43 patients) and in radiation bowel disease (n = 18 patients). Tissue samples obtained from postoperative colectomy specimens in which the intramural vessels had been perfused with barium sulphate suspension were examined. Microradiography was used to study vascular pattern which was abnormal in radiation bowel disease. A recently described radiograph fluorescence system was used to estimate barium concentration, and hence microvascular volume. The radiation group showed a highly significant reduction in barium concentration (p less than 0.001), when compared with the normal group. This reduction was diffuse in samples from 15 patients who had received combined intracavity and external radiotherapy, but localised in two patients who had received intracavity treatment only. It is concluded that microvascular compromise is an important factor in the natural history of radiation bowel disease.