MYOCARDIAL TOMOGRAPHY WITH TECHNETIUM-99M-TETROFOSMIN DURING INTRAVENOUS-INFUSION OF ADENOSINE-TRIPHOSPHATE

The purpose of this study was to determine the biodistribution of Tc-9 9m-tetrofosmin during intravenous infusion of adenosine triphosphate ( ATP) and to evaluate the potential diagnostic value of myocardial tomo graphy with Tc-99m-tetrofosmin during ATP infusion for the detection o f coronary artery disease. Methods: Myocardial Tc-99m-tetrofosmin imag ing with ATP infusion and coronary arteriography were performed on 65 patients with suspected coronary artery disease, ATP was infused intra venously at a rate of 0.16 mg/kg/min for 5 min, and 370 MBq of Tc-99m- tetrofosmin was injected 3 min after the start of ATP infusion. Myocar dial SPECT imags were obtained 60 min later. Then, 740 MBq of Tc-99m-t etrofosmin was administered at rest, and myocardial SPECT was repeated . Regional uptakes of Tc-99m-tetrofosmin were scored from 4, normal, t o 0, no activity. Serial 5-min planar images were obtained in the ante rior projection at 15, 30, 45 and 60 min after the Tc-99m-tetrofosmin injection in 10 patients, Heart-to-lung and heart-to-liver count ratio s were defined from the serial planar images. Results: Adverse effects of ATP infusion were mild and transient, A heart-to-lung ratio after ATP infusion was high even at 15 min (3.40 +/- 0.33) and gradually inc reased with time. A heart-to-liver ratio after ATP was 0.53 +/- 0.40 a t 15 min and increased with time. A heart-to-liver ratio reached 0.99 +/- 0.25 (p < 0.01) after 45 min and 1.32 +/- 0.36 (p < 0.01) after 60 min, The sensitivity and specificity for detecting coronary artery di sease by myocardial SPECT with ATP were 89% (39/44) and 86% (18/21), r espectively. Conclusion: This study shows the favorable biodistributio n of Tc-99m-tetrofosmin after intravenous infusion of ATP, A one-day i maging protocol of Tc-99m-tetrofosmin tomography with ATP is feasible and has high diagnostic accuracy for coronary artery disease.