99mTc-pyrophosphate imaging in experimental mesenteric infarction: relationship of tracer uptake to the degree of ischemic injury.

Four-hour balloon occlusion of the cranial mesenteric artery in 13 dogs produced a spectrum of widespread ischemic injury to the small bowel ranging from superficial mucosal infarction to transmural infarction. Twenty-four hours after the beginning of balloon occlusion, 15 mCl of 99mTc-pyrophosphate was injected into the cranial mesenteric artery in 8 dogs and into a peripheral vein in 5. Gamma camera imaging of the abdomen followed three hours later. Four of 8 dogs injected intra-arterially showed positive images with full-thickness mucosal or transmural infarction. The 4 intravenously injected dogs with positive images had transmural infarction. Only minimal ischemic injury with superficial mucosal infarction was found in the 5 dogs with negative images. Tracer uptake per gram infarcted tissue was highest after intra-arterial injection. It was concluded that 99mTc-pyrophosphate allows external imaging of extensive intestinal infarctions after both intra-arterial and intravenous injection.