Microangiographic pattern in the small intestine of the cat after irradiation.

The microangiographic pattern in the experimentally irradiated small intestine of the cat was studied with two different techniques: infusion of Micropac and X-ray exposure on Kodak spectroscopic plates, and infusion of India ink and clearing the tissue as described by Spalteholtz. Bowels were irradiated with 10 to 30 Gy and examined from 4 days up to 4 months after irradiation. During the acute gastrointestinal radiation injury the mucosa was denuded and the microangiographic pattern strongly divergent from normal. After regeneration the vascular pattern depended on the dose given. After up to 15 Gy the vascular pattern looked quite normal even after 4 months. After higher doses and poor mucosal regeneration the vascular pattern did not return to normal. With 30 Gy no regeneration of the mucosal vascular pattern took place. Decreased vascularity was observed in all layers of the bowel. Variation in luminal width and obstruction of vessels were more frequent with higher doses.