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Reliability of left ventricular ejection fraction calculated with gated myocardial perfusion single photon emission computed tomography in patients with extensive perfusion defect

IntroductionGated myocardial perfusion scintigraphy (g-MPS) provides functional information on the left ventricle (LV) apart from the perfusion status. Computer algorithm-based LV ejection fraction (EF) calculated from resting g-MPS has been found to be reliable in patients with normal perfusion. However, its role in patients with extensive perfusion defects is not clear. AimTo find the reliability of LVEF calculated from resting g-MPS in patients with extensive perfusion defects (>25% of LV myocardium) and to correlate this with echocardiography and multigated radionuclide ventriculography (RNV). Materials and methodsThirty patients with fixed perfusion defect of size greater than or equal to 25% of LV myocardium on rest g-MPS study were included. EF was calculated using three software packages: Emory Cardiac Toolbox, Myometrix, and quantitative gated single photon emission computed tomography (SPECT)/quantitative perfusion SPECT. The patients underwent RNV (gold standard) and echocardiography within a week of the g-MPS. Agreement among the EF values obtained by different methods was determined using Bland–Altman analysis. Correlation among the EF values was measured using Spearman's rank correlation. ResultsThirty patients (23 male; seven female; mean age 51 years, range 32–70 years) were included prospectively. The average size of perfusion defect was 38% of the LV myocardium (range 25–56% of LV). The average ejection fraction values were 33% for Emory Cardiac Toolbox (range 11–50%), 31% for Myometrix (range 18–46%), and 33% for quantitative gated SPECT/quantitative perfusion SPECT (range 17–49%). The mean EF on echocardiography was 37% (range 22–60%), whereas that of RNV was 33% (range 10–50%). The data were normally distributed. There was statistically significant positive agreement between algorithm-based EF measurements to the gold standard RNV. ConclusionThis study suggests that EF calculations, from g-MPS SPECT data using different software, have high agreement with the gold standard RNV even in patients with extensive perfusion defects.