ABSTRACT
Purpose To evaluate the correlation and consistency of left ventricular ejection fraction (LVEF) obtained by ECG-gated myocardial perfusion SPECT (GMPS) using four formulae (R0-R3) of ECToolbox software and findings on equilibrium radionuclide angiography (ERNA), and to determine the optimal diagnostic thresholds by using the four formulae. Materials and Methods A total of 38 patients with myocardial infarction and 65 patients with suspected coronary heart disease underwent both 99Tcm-MIBI rest GMPS and 99Tcm-RBC ERNA within a week. The LVEF values calculated by ECToolbox R0, R1, R2 and R3 were compared with those obtained by ERNA, and compared with ERNA results, the optimal diagnostic thresholds of the four formulae (R0-R3) were assessed by receiver operating characteristic (ROC) curves. Results The results calculated by the formulae (R0-R3) presented a significant positive correlation with that obtained by ERNA [mean LVEF value by ERNA (54.6±17.5)%, mean LVEF value by formulae R0-R3 (64.1±15.7)%, (56.3±15.1)%, (69.9±17.9)% and (56.7±13.6)%, respectively, r=0.899, 0.898, 0.890, 0.895; P<0.01]. All mean LVEF values calculated by the four formulae were higher than that by ERNA, and the difference was significant (P<0.05). LVEF≥50%obtained by ERNA was considered as normal diagnostic value, the optimal diagnostic thresholds of R0-R3 were 56.5%, 51.5%, 64.5% and 52.5%, respectively. Conclusion The results calculated by R0, R1, R2 and R3 in the ECToolbox software and that by ERNA show significant correlation and difference for the assessment of LVEF. Thus it is advisable to stick to one formula in the follow-up of each patient and select correspondent threshold in the clinical diagnosis.