Myocardial uptake of a (99m)Tc-nitroheterocycle in a swine model of occlusion and reperfusion.
The purpose of this study was to evaluate the window for scan positivity of the radiolabeled nitroheterocycle (99m)Tc-BRU-59-21 in the peri-ischemic period using a swine model of occlusion and reperfusion.


METHODS
A balloon catheter was placed in the left anterior descending coronary artery in each of 19 domestic swine. Blood flow and hemodynamic measurements were made at baseline, during occlusion, and at 15 and 180 min after reperfusion. A dose of approximately 925 MBq (99m)Tc-BRU-59-21 was injected before a brief (6 min) period of coronary occlusion at the following times: 15 min (n = 2), 5 min (n = 2), and 2.2 min (n = 5). In 5 experiments the dose was injected 15 min after reperfusion. Animals underwent SPECT imaging 3 h later. Animals were then killed, and hearts were removed, sliced, stained with triphenyl tetrazolium chloride, and imaged on the detector.


RESULTS
The risk region became ischemic during occlusion on the basis of severe reduction in blood flow and lactate production, but necrosis occurred in only 3 experiments. Focal tracer uptake was seen in the risk region in animals injected 5 and 2.2 min before occlusion but not in animals injected 15 min before occlusion and 15 min after reperfusion.


CONCLUSIONS
The window for scan positivity for (99m)Tc-BRU-59-21 injected in the peri-ischemic period is short using this model of balloon occlusion and reperfusion in swine.
Division of Cardiology, Rhode Island Hospital, Providence 02903, USA.
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LL
Johnson
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Schofield
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Donahay
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Mastrofrancesco
D000818:Animals; D003326:Coronary Circulation; D006439:Hemodynamics; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism; D009593:Nitroimidazoles / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013552:Swine; D015899:Tomography, Emission-Computed, Single-Photon
D009593:Nitroimidazoles; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C411943:technetium Tc 99m-BRU-59-21