Quantitative planar imaging of glucose metabolic activity in myocardial segments with exercise thallium-201 perfusion defects in patients with myocardial infarction: comparison with late (24-hour) redistribution thallium imaging for detection of reversible ischemia.

Exercise thallium-201 24-hour redistribution imaging and myocardial glucose metabolism with F-18-deoxyglucose were used to identify reversible ischemia in 30 patients with previous myocardial infarction. Metabolic images were obtained using a planar gamma camera fitted with a rotating tungsten collimator. Of 184 exercise thallium perfusion defects, late redistribution occurred in 88. Metabolic evidence for reversibility (metabolism-perfusion mismatch) was identified in 91% of these 24-hour reversible segments. However, 72% of the segments with fixed perfusion defects also had residual ischemia by F-18-deoxyglucose. Out of 26 fixed severe thallium defects, 69% had F-18-deoxyglucose evidence for residual ischemia. A subset of 14 patients underwent serial exercise thallium scintigraphy or gated equilibrium radionuclide angiography after revascularization or medical therapy. Out of 46 fixed thallium defects in these patients, 30 demonstrated serial scintigraphic improvement. F-18-deoxyglucose-thallium mismatch was present in 81% of these segments, but was absent in the majority of the unimproved segments. Thus quantitative planar imaging of myocardial glucose metabolism with F-18-deoxyglucose using a well-collimated gamma camera can detect clinically important reversible ischemia in segments with fixed thallium defects at late redistribution imaging.