Assessment of left ventricular ejection fraction measured by quantitative gated SPECT

Purpose: The purpose of this study was to evaluate the reliability of left ventricular ejection fraction (LVEF) measured by quantitative gated SPECT (QGS). We compared the efficacy of LVEF assessment among Tc-99m tetrofosmin gated SPECT imaging, contrast left ventriculography (LVG), and first-pass radionuclide angiography (FP). Patients: One-hundred and seven patients with ischemic heart disease underwent QGS and LVG simultaneously within 3 months, and 92 of the 107 patients also underwent FP at the same time. Results: QGS progressively overestimated LVEF at the lower range of end-systolic volume (ESV), especially in patients with small hearts. Moreover, the QGS technique systemically tended to underestimate LVEF in comparison with LVG. However, linear regression analysis demonstrated a good correlation between the LVEF values measured by QGS and those measured by both LVG (p<0.0001) and FP (p<0.0001). Conclusion: Although QGS has a tendency to overestimate LVEF in patients with small hearts, and to systemically underestimate LVEF compared with LVG, this technique is still a reliable clinical tool for measurement of LVEF.