Objective: Echocardiography (echo) has been considered as a standard for evaluating LV function in clinical practice. With the application of ECG-gated technology, myocardial perfusion SPECT can provide information not only for myocardial perfusion but also for ventricular function. The purpose of this study is to compare ejection fraction (EF), end-diastolic volume (EDV) and end-systolic volume (ESV) assessed by echo and Tl-201 gated SPECT (GSPECT).
Methods: Sixty-four consecutive patients with suspected or known coronary artery disease were enrolled in this study. All pataients underwent both echo and GSPECT. The gated SPECT data was processed by a commercially software (QGS 4.0). EF, EDV and ESV assessed by these two modalities were compared.
Results: The correlation of echo and GSPECT was good for EF and ESV (r=0.81, p<0.0001; and r=0.88, p< 0.0001), and was modest for EDV (r=0.60, p<0.0001). There was no significant difference for EF assessed by echo and GSPECT (63.6+-13.3 and 62.5+-15.0, p=0.23). The EDV and ESV assessed by GSPECT were significantly smaller than those by echo (66.6+-31.3 and 106.3+-44.0, p<0.0001; 28.4+-27.9 and 40.2+-29.4, p<0.0001). The difference of estimated EF between echo and GSPECT is 4.9+-8.2 for ESV by GSPECT >20 ml, but is -2.0+-8.2 for ESV <20 ml (p<0.001).
Conclusions: There were modest to good correlations for the functional parameters assessed by echo and GSPECT. EF by echo and GSPECT seemed to be interchangeable, but EDV and ESV by GSPECT were significnatly underestimated. EF by GSPECT tended to be underestimated for larger volumes on GSPECT, but overestimated for smaller volumes.