Infrared imaging contribution for intestinal ischemia detection in wound healing

PURPOSE: To study thermal variations obtained through infrared image in rats, and to evaluate the relationship between intestinal ischemic time and histopathological findings. METHODS: Thirty Wistar rats were operated after distribution in 5 groups with different times of ischemia. Thermograms were obtained by using a infrared camera. The surgical technique has been standardized for all groups: abdominal cavity opening by a 5cm length incision in the midline, abdominal wall plans section and cavity exposure, and exteriorization of the intestine. In group I (control), it was proceeded only laparotomy without superior mesenteric artery ligature. After first thermogram done, incision was closed with continuing suture. In each rat in groups II, III, IV and V, the superior mesenteric artery was located at its origin on abdominal aorta, dissected and occluded with a vascular microclamp, subjecting the intestine to ischemia in variable times. RESULTS: Rats submitted to a 30 minutes ischemia presented reactive hyperemia, thermal differential of 1.8°C and normal pathological examination. The 1 hour ischemia produced reactive hyperemia with ischemic areas, thermal differential of 1.0°C and injuries at villosities' tips. However, the 90 minutes ischemia had not shown reactive hyperemia with large ischemic areas, thermal differential of -1.0°C and injury in the upper third of the villosities. The 2 hours ischemia demonstrated a severe ischemia, thermal differential of -2.0°C and injury throughout the all villosities' extension. CONCLUSION: It has been possible studying thermal variations through infrared image in rats, showing correlation between thermal response in thermograms, ischemic time and histopathological findings.