Quantitative Assessment of Coronary Perfusion Reserve on Normal and Abnormal Myocardium with TC-99m Hexamibi, Comparison with TI-201.

In 12 cases with normal coronary angiogram and 29 patients with abnormal coronary angiogram, 15 mCi Tc-99m hexamibi and 2 mCi Tl-201 were injected during exercise on separate days and planar imaging was applied. A second injection of 15 mCi of Tc-99m hexamibi was performed with the patients at rest one day later. Rest Tl-201 scintigraphy was performed 3 to 4 h later following exercise imaging without a second injection. Quantitative assessment of both Tc-99m hexamibi and Tl-201 were performed in 205 left ventricle segments and coronary perfusion reserve (cpr) of each segment was calculated on Tc-99m hexamibi and Tl-201 studies, from exercise to rest. There was good correlation for the cpr of normal or abnormal myocardium with two radiopharmaceuticals Myocardial defect uptake was nearly identical, yielding agreement in 93.8% of the myocardial segments in patients with coronary artery disease (CAD) and 88.3% of the myocardial segments in normal patients. We conclude that Tc-99m hexamibi is a sensitive myocardial flow marker. However, a second injection was needed to asses regional cpr within this protocol.