Assessment of left ventricular diastolic function with electrocardiography-gated myocardial perfusion SPECT: Comparison with multigated equilibrium radionuclide angiography

Background. Technetium-labeled myocardial! perfusion tracers allow the simu ltaneous assessment of myocardial perfusion and left ventricular function b y electrocardiography (ECG)-gated myocardial perfusion single photon emissi on computed tomography (SPECT). This study evaluates left ventricular systo lic and diastolic function by ECG-gated SPECT with the use of higher framin g (32 frames per cardiac cycle) data acquisition. Methods and Results. After receiving an injection of technetium 99m tetrofo smin, 48 patients with cardiac diseases were examined by ECG-gated myocardi al perfusion SPECT with a 3-headed gamma camera. During gated data collecti on, 32 frames per cardiac cycle were acquired over 360 degrees in 60 steps, each of which consisted of 60 beats. Immediately thereafter, the 32 frames taken at each projection angle were combined into 16-frame and 8-frame dat a sets. Left ventricular end-diastolic volume (LVEDV, in milliliters), left ventricular end-systolic volume (LVESV, in milliliters), and left ventricu lar ejection fraction (LVEF, percentage) were automatically calculated from the 32-frame, 16-frame, and 8-frame gated data sets. Left ventricular time -volume curves from the 3 data sets were generated by Fourier curve fitting analysis with the use of 3 harmonies, and then peak filling rate (PFR, per second) was measured. Twenty-nine patients also underwent multigated equil ibrium radionuclide angiography (ERNA) to determine the LVEF and PFR. Combi ning the 32-frame data into 16-frame and 8-frame data sets from the 48 pati ents generated a smaller LVEDV and a larger LVESV, and LVEF was significant ly lower in accordance with the decreasing number of frames. Compared with ERNA studies (n=29), the Bland-Altman method showed underestimated LVEFs an d larger 95% limits of agreement in lower framing gated SPECT. Conclusions. Left ventricular functional parameters obtained from 32-frame gated SPECT correlated closely with those determined by ERNA studies. ECG-g ated SPECT with 32-frame data can provide comprehensive information with wh ich to evaluate many types of cardiac diseases.