Comparison of cardiac magnetic resonance with gated SPECT for evaluation of left ventricular function and volumes in patients with severe and multiple myocardial perfusion defects

Abstract

Objectives Gated SPECT is an accurate technique for assessment of myocardial perfusion (MP), left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV). However recent studies have concluded that there are large discrepancies in assessment of LVEF and volumes by gated SPECT in patients with multiple severe myocardial perfusion defects. We sought to investigate the correlation between LVEF and volumes calculated by gated SPECT and cardiac magnetic resonance (CMR) in patients with severe multiple perfusion defects who are referred for CMR. Methods Twenty-nine patients (20 male and 9 female, mean age: 63 years ± 11) with multiple severe fixed perfusion defects (mean 5 ± 3 segments) were referred to undergo CMR. The average time between CMR and SPECT was 4 weeks. LVEF, EDV, and ESV were derived automatically from gated SPECT. In the CMR studies, the endocardial and epicardial borders were delineated manually in the short axis planes to calculate the LVEF and volumes. Results The different parameters were compared using linear regression, and correlation coefficients were calculated. Substantial correlation was found between CMR and gated SPECT for EDV: r = 0.7, p < 0.001. Moderate correlation between CMR and gated SPECT for LVEF: r = 0.5, p < 0.007 and ESV r =0 .53, p < 0.003. Conclusion Our data showed that the gated SPECT correlates substantially with MRI for measurement of EDV and moderately for ESV and LVEF in patients with multiple and severe perfusion defects. Thus, when accurate measurement is required, cardiac MRI is recommended.