Optimization of SPECT Measurement of Myocardial Blood Flow with Corrections for Attenuation, Motion, and Blood Binding Compared with PET.

Myocardial blood flow (MBF) and myocardial flow reserve (MFR) measured with PET have clinical value. SPECT cameras with solid-state detectors can obtain dynamic images for measurement of MBF and MFR. In this study, SPECT measurements of MBF made using Tc-99m-tetrofosmin were compared with PET in the same patients. Methods: Thirty-one patients underwent PET MBF rest-stress studies performed with Rb-82 or N-13-ammonia within 1 mo of their SPECT study. Dynamic rest-stress measurements were made using a SPECT camera. Kinetic parameters were calculated using a 1-tissue-compartment model and converted to MBF and MFR. Processing with and without corrections for attenuation (+AC and -AC), patient body motion (+MC and -MC), and binding of the tracer to red blood cells (+BB and -BB) was evaluated. Results: Both +BB and +MC improved the accuracy and precision of global SPECT MBF compared with PET MBF, resulting in an average difference of 0.06 +/- 0.37 mL/min/g. Global MBF and detection of abnormal MFR were not significantly improved with +AC. Global SPECT MFR with +MC and +BB had an area under the receiver-operating curve of 0.90 (+AC) to 0.95 (-AC) for detecting abnormal PET MFR less than 2.0. Regional analysis produced similar results with an area under the receiver-operating curve of 0.84 (+AC) to 0.87 (-AC). Conclusion: Solid-state SPECT provides global MBF and MFR measurements that differ from PET by 2% +/- 32% (MBF) and 2% +/- 28% (MFR).