INDIUM 111 OXINE-LABELED LEUKOCYTES FOR EARLY DIAGNOSIS OF ISCHEMIC ENTEROCOLITIS

The feasibility of the use of indium 111 oxine-labeled autologous leukocytes for the diagnosis of ischemic enterocolitis in vivo was examined in an experimental model of ischemia in dogs. A 30-cm segment of small intestine was devascularized by ligating the arteries and veins from the last arcade in 7 dogs. A sham operation was performed in 3 control dogs. 111In oxine-labeled autologous white blood cells were infused 3.5 hours after operation. Anterior and lateral nuclear scanning was performed at 6 and 24 hours postinfusion with a gamma camera equipped with a low-energy magnifying multihold collimator. The animals were killed after 24 hours. The gross and microscopic appearance of the bowel was evaluated. The radioactivity in the serial specimens of the bowel was measured. In vivo scans were positive (ie, increased uptake in the bowel loop) in all dogs with intestinal ischemia at 6 and 24 hours. No significant uptake was noted in control dogs. Rectilinear scan of the bowel removed at autopsy showed a correlation between the area of infarction and tracer accumulation. In addition, there was a progressive decrease in uptake of 111In oxine from the center of the ischemic lesions to the periphery. Forty percent of the total radioactivity was measured at the center of the lesion, whereas only 6.5% was present at 22.5 cm from the center. Thus the ratio between the ischemic and normal tissue was 10:1 (range, 6.5 to 16). These studies demonstrate that 111In oxine-labeled autologous white blood cells can be used for the diagnosis of ischemic enterocolitis. Further evaluation of the usefulness in carefully controlled circumstances in newborn infants with necrotizing enterocolitis is required. © 1991.