A comparison and validation of blood-pool imaging and ECG-gated SPET myocardial perfusion imaging to assess left ventricular ejection fraction

The aim of this study was to validate the accuracy of left ventricular ejection fraction (LVEF) obtained by quantitative gated single photon emission tomography (QGS) perfusion imaging in comparison with gated blood-pool imaging. Resting gated myocardial perfusion imaging was performed in 269 patients with suspected or known coronary artery disease, and followed by equilibrium nuclear cardiac blood-pool imaging in one week. The later was considered as the reference standard. The LVEF from both methods were analyzed. The LVEF were calculated with QGS using Cedars Cardiac Quantification software. We found that LVEF from QGS and blood-pool (Bp)-LVEF were highly correlated (r=0.819, <0.001). Taken into consideration that QGS-LVEF was significantly different from Bp-LVEF (mean ± SD: 57.77% ± 19.28% vs 54.23% ± 15.41%, P<0.05), data were further analyzed by grouping participants based on end-systolic ventricular volume (ESV). QGS-LVEF was not significantly different from Bp-LVEF in the group where that ESV was larger than 15m, (mean ± SD: 52.71% ± 16.11% vs 51.83% ± 15.33%, P>0.05), whereas when ESV was smaller than 15 mL, QGS-LVEF was significantly higher than Bp-LVEF (mean ± SD: 80.53% ± 7.01%vs 65.06% ± 10.37%, P<0.05). Our findings demonstrate that when ESV values are larger than 15 mL, QGS- LVEF could replace Bp-LVEF. However, when ESV value is smaller than 15 mL, LVEF should be assessed in combination with blood-pool imaging.