Left ventricular volumes and ejection fraction calculated from quantitative electrocardiographic-gated Tc-99m-tetrofosmin myocardial SPECT

We compared the left ventricular (LV) end-diastolic volume (EDV), end-systo lic volume (ESV) and ejection fraction (LVEF) as calculated by Cedars autom ated quantitative gated SPECT (QGS) to those determined by first-pass radio nuclide angiography (FPRNA) and contrast left ventriculography (LVG) in a g roup of 21 patients (mean age 61.4 +/- 9.2 y). Methods: A total of 740 MBq Tc-99m-tetrofosmin was administered rapidly into the right cubital vein at rest, and FPRNA was performed using a multicrystal gamma camera. One hour a fter injection, QGS was performed with atemporal resolution of 10 frames pe r R-R interval. LVG was performed within 2 wk. Results: The EDV, ESV and LV EF calculated by QGS were highly reproducible (intraobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; interobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; P < 0.01) and were more consistent than those determin ed by FPRNA (intraobserver, r = 0.97, r = 0.95 and r = 0.93, respectively; interobserver, r = 0.86, r = 0.96 and r = 0.91, respectively; P < 0.01). Th ere was a good correlation between EDV, ESV and LVEF by FPRNA and those by LVG (r = 0.61, r = 0.72 and r = 0.91, respectively; P < 0.01), and there wa s an excellent correlation between QGS and LVG (r = 0.73, r = 0.83 and r = 0.87, respectively; P < 0.01). The mean EDV by QGS (100 +/- 11.3 mL) was si gnificantly lower than by FPRNA (132 +/- 16.8 mL) or LVG (130 +/- 8.1 mL), and the mean ESV by QGS (53.8 +/- 9.3 mL) was lower than by FPRNA (73.0 +/- 13.3 mL). Ejection fraction Values were highest by LVG (57.1% +/- 3.2%), t hen QGS (51.8% +/- 3.0%) and FPRNA (48.9% +/- 2.4%). Conclusion: QGS gave m ore reproducible results than FPRNA. LV volumes and LVEF calculated by QGS correlated well to those by LVG.