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

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 ofLVEF and volumes by gated SPECT in patients withmultiple severe myocardial perfusion defects.Wesought to investigate the correlation betweenLVEFand volumes calculated by gated SPECTand 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 betweenCMRand SPECTwas 4 weeks.LVEF,EDV, and ESVwere derived automatically fromgated 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 coefficientswere calculated. Substantial correlationwas found betweenCMRand gated SPECTfor EDV: r=0.7, p 0.001.Moderate correlation between CMR and gated SPECT for LVEF: r=0.5, p 0.007 andESV r =0 .53, p 0.003. Conclusion: Our data showed that the gated SPECT correlates substantially with MRI for measurement ofEDVandmoderately forESVandLVEFin patients with multiple and severe perfusion defects. Thus, when accurate measurement is required, cardiac MRI is recommended.