Intestinal infarction was produced in 10 dogs by means of microsphere embolization. Intravenous and intra-arterial injections of 99mTc-pyrophosphate were then administered and in vivo and in vitro scintigrams obtained. Positive in vitro images of the infarctions were seen for all the dogs and positive in vivo radionuclide accumulation was seen for all the dogs which had intra-arterial injections. Only 1 of the 4 dogs with intravenous injection showed positive in vivo imaging of the infarction.