Evaluation of left ventricular volumes and ejection fraction by gated SPECT and cardiac MRI in patients with dilated cardiomyopathy.

Abstract

The goal of this study was to evaluate the accuracy of gated single photon emission computed tomography (SPECT) in the assessment of left ventricular (LV) end-diastolic/end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) in patients with dilated cardiomyopathy, using cardiac magnetic resonance imaging (MRI) as the reference method. Furthermore, software-specific characteristics of Quantitative Gated SPECT (QGS), Emory Cardiac Toolbox (ECTB) and 4D-MSPECT were analysed. Thirty-six patients with dilated cardiomyopathy who underwent gated (99m)Tc-methoxyisobutylisonitrile SPECT and cardiac MRI were included. LV EDV, ESV and LVEF values of gated SPECT were calculated using QGS, ECTB and 4D-MSPECT. The correlation between the results of gated SPECT and cardiac MRI was excellent for EDV [R = 0.872 (QGS), R = 0.879 (ECTB), R = 0.869 (4D-MSPECT)], ESV [R = 0.908 (QGS), R = 0.897 (ECTB), R = 0.880 (4D-MSPECT)] and LVEF [R = 0.794 (QGS), R = 0.763 (ECTB), R = 0.710 (4D-MSPECT)]. EDV and ESV assessed by QGS did not differ significantly from those assessed by cardiac MRI (all p = NS), whereas EDV and ESV were overestimated by ECTB and 4D-MSPECT compared with cardiac MRI (all p < 0.05). LVEF was overestimated by QGS, ECTB and 4D-MSPECT compared with cardiac MRI (all p < 0.05). The correlation between gated SPECT and cardiac MRI is excellent for LV volume and LVEF values calculated by QGS, ECTB and 4D-MSPECT in patients with dilated cardiomyopathy. However, algorithm-varying over- or underestimation of LV volumes and LVEF should be accounted for in the clinical context.