Comparison between 99mTc-sestamibi gated myocardial perfusion SPECT and echocardiography in assessment of left ventricular volumes and ejection fraction--effect of perfusion defect and small heart.

BACKGROUND

Agreement between gated myocardial perfusion SPECT (GSPECT) and echocardiography (ECHO) in the calculation of left ventricular end-diastolic volume (EDV), end-systolic volume (ESV) and LVEF was assessed. Effect of perfusion defect and small hearts on this agreement was obtained. Because ECHO is a routine and widely used noninvasive modality for this purpose, we chose this technique for comparison with GSPECT.

MATERIAL AND METHODS

In a prospective study, 50 consecutive patients (age = 59.7 ± 10.64 years) underwent rest Tc99m-sestamibi GSPECT and 2-D ECHO. The LVEF, EDV and ESV were calculated using QGS (Quantitative Gated SPECT) software.

RESULTS

Fourteen (28%) patients had perfusion defect in rest phase tomograms, while 36 (72%) had no perfusion defect. There was a significant correlation between two modalities in calculation of EDV, ESV and LVEF (all: p < 0.001, Pearson's correlation coefficients: r = 0.764, 0.831 and 0.813, respectively). A good correlation was noticed even in small hearts or in patients with or without previous myocardial infarction. There was a significant difference between GSPECT and ECHO in patients with no perfusion defect as well as in patients with small heart (ESV < 25 ml). On the other hand, no remarkable difference was noticed between two techniques in the presence of perfusion defect or in patients with ESV ≥ 25 ml.

CONCLUSION

There was a good agreement between EDV, ESV and LVEF derived from GSPECT and ECHO. There was a significant difference between two modalities in small hearts and in patients without perfusion defect, although in larger ventricles or in the presence of myocardial infarction no remarkable difference between two modalities was noticed.