Estimation of myocardial perfusion and viability using simultaneous Tc-99m-tetrofosmin-FDG collimated SPECT

This study was designed to elucidate the usefulness of crosstalk correction for dual-isotope simultaneous acquisition (DISA) with Tc-99m-tetrofosmin a nd FDG in estimating myocardial perfusion and viability. Methods: Eighteen patients with coronary artery disease were studied. First, SPECT was perfor med with a low-energy high-resolution collimator after a single injection o f Tc-99m-tetrofosmin (single Tc-99m-tetrofosmin). Second, PET and DISA with an ultra-high-energy collimator were performed after glucose loading and a n injection of FDG. DISA was designed to operate with simultaneous 3-channe l acquisition, and weighted scatter correction of crosstalk from the F-18 p hotopeak to the Tc-99m photopeak was performed by modification of an existi ng dual window technique. The FDG SPECT images were compared with the image s obtained by PET. Both crosstalk-corrected and uncorrected Tc-99m-tetrofos min images were generated and compared with the single Tc-99m-tetrofosmin i mages. Results: Regional percentage uptake of FDG agreed well between DISA and PET. However, regional percentage uptake of Tc-99m-tetrofosmin was gene rally higher on the uncorrected Tc-99m-tetrofosmin images than on the singl e Tc-99m-tetrofosmin images, especially in areas of low flow (percentage co unt of Tc-99m-tetrofosmin greater than or equal to 50%). The crosstalk corr ection contributed to improving the agreement between regional percentage u ptakes and significantly improved the detectability of myocardial perfusion -metabolism mismatching. Conclusion: With 3-channel acquisition and weighte d-scatter correction of crosstalk from the F-18 photopeak to the (TC)-T-99m photopeak, DISA with Tc-99m-tetrofosmin and FDG is feasible for assessing regional myocardial perfusion and viability.