The use of intraperitoneal xenon for early diagnosis of acute mesenteric ischemia

We evaluated the technique of intraperitoneal use of xenon Xe 133, previously described for the diagnosis of early intestinal strangulation obstruction in rats and dogs, for the recognition of acute mesenteric vascular occlusion in these animals. ¹³³Xe was injected intraperitoneally into five groups of six rats: control, sham operation, superior mesenteric artery (SMA) ligation, superior mesenteric vein ligation, and portal vein ligation. Residual γ-activity was monitored by external counting and camera imaging. At 30 minutes after injection, the activity was significantly higher in the rats from the three groups with vascular ligation than in the control and sham operation animals (P < 0.001). γ-Camera images reflected these findings, with positive images only in the rats that underwent vascular ligation. 'Blinded' readings of the 30 sets of scans confirmed the diagnostic accuracy of the images. Results were essentially the same in a second series of experiments in eight control dogs and six dogs with balloon occlusion of the SMA. Concentrations of isotope in ischemic intestine ranged from 10³ to 10⁵ times the levels in adjacent normal bowel. These levels and the positive images appeared early, prior to the development of tissue necrosis. The intraperitoneal use of ¹³³Xe therefore continues to show promise for the recognition of patients with early intestinal ischemia.