REST MYOCARDIAL PERFUSION METABOLISM IMAGING USING SIMULTANEOUS DUAL-ISOTOPE ACQUISITION SPECT WITH TECHNETIUM-99M-MIBI/FLUORINE-18-FDG/

The purpose of this study was to develop a dual-isotope simultaneous a cquisition (DISA) protocol using a multihead SPECT camera equipped wit h an ultrahigh-energy (UHE) collimator to evaluate simultaneously rest cardiac perfusion and metabolism with Tc-99m-MIBI/(18)FDG. Methods: P hysical measurements were first performed with phantoms to develop the acquisition protocol. Fifteen patients underwent DISA-SPECT with Tc-9 9m-MIBI/(18)FDG to validate the protocol. To evaluate the quality of t he Tc-99m-MIBI images acquired with the UHE collimator, four patients underwent a resting Tc-99m-MIBI scan acquired with a high-resolution, low-energy collimator prior to DISA-SPECT. Results: With a window of 2 0% for both photopeaks and a Tc-99m/F-18 concentration ratio of 3.2:1, the spillover from F-18 into the Tc-99m window is 6% of the counts in the window for normal subjects. Phantom images clearly demonstrated d efects measuring 2 x 1 and 2 x 0.5 cm. Technetium-gsm-MIBI images obta ined with the UHE and high-resolution collimators provided similar dia gnostic information. Using a stenosis of >70% as criteria to diagnose coronary artery disease, DISA-SPECT had a sensitivity of 100% and a po sitive predictive value of 93%. Conclusion: Simultaneous evaluation of rest myocardial perfusion/metabolism with a multihead SPECT camera eq uipped with an UHE collimator is possible using Tc-99m-MIBI/(18)FDG Wi th a dual-isotope simultaneous acquisition protocol.