Evaluation of left ventricular volumes and ejection fraction by 99mTc-MIBI gated SPECT and 18F-FDG gated PET in patients with prior myocardial infarction.

BACKGROUND: This study aimed to compare the accuracy of gated-SPECT (GSPECT) and gated-PET (GPET) in the assessment of left ventricular (LV) end-diastolic volumes (EDVs), end-systolic volumes (ESVs) and LV ejection fractions (LVEFs) among patients with prior myocardial infarction (MI). METHODS: One hundred and sixty-eight consecutive patients with MI who underwent GSPECT and GPET were included. Of them, 76 patients underwent CMR in addition to the two imaging modalities. The measurements of LV volumes and LVEF were performed using Quantitative Gated SPECT (QGS), Emory Cardiac Toolbox (ECTB), and 4D-MSPECT (4DM). RESULTS: The correlation between GPET, GSPECT, and CMR were excellent for LV EDV (r = 0.855 to 0.914), ESV (r = 0.852 to 0.949), and LVEF (r = 0.618 to 0.820), as calculated from QGS, ECTB, and 4DM. In addition, subgroup analysis revealed that EDV, ESV, and LVEF measured by GPET were accurate in patients with different extents of total perfusion defect (TPD), viable myocardium, and perfusion/metabolic mismatch. Furthermore, multivariate regression analysis identified that mismatch score was associated with the difference in EDV (P < 0.05) measurements between GPET and CMR. CONCLUSIONS: In patients with MI, LV volumes and LVEF scores measured by both GSPECT and GPET imaging were comparable to those determined by CMR, but should not be interchangeable in individual patients.

The feasibility of 18F-FDG gated positron emission tomography (PET) for left ventricular dyssynchrony assessment in comparison with 99mTc-MIBI gated single-photon emission computed tomography (SPECT) among patients with prior myocardial infarction.

Background: Phase analysis by 99mTc-MIBI gated single-photon emission computed tomography (GSPECT) has been considered to be an adequate method in the validation of left ventricular (LV) dyssynchrony. Compared with GSPECT, prior myocardial infarction patients with myocardial perfusion defects but myocardial viability usually show preserved uptake of 18F-FDG, and extensive myocardium is detected by 18F-FDG gated positron emission tomography (GPET). Thus, theoretically, it should be more accurate. The aim of this study was to investigate the feasibility of GPET for LV dyssynchrony assessment in comparison with GSPECT among infarction patients. Methods: A total of 146 patients with infarction underwent 2 consecutive days of GSPECT and GPET examinations. Quantitative gated SPECT-derived LV phase analysis was applied to GPET and GSPECT data to assess the presence of LV dyssynchrony via histogram bandwidth (BW) and phase standard deviation (SD). The correlation and agreement of BW and SD between GSPECT and GPET were examined. Factors (i.e., total perfusion defect, scar and mismatch) related to the discrepancies of LV dyssynchrony (i.e., BW and SD) in GPET and GSPECT were assessed by univariate and multivariate regression analysis. Results: A moderate correlation between GPET and GSPECT was found in the measurements of BW (r=0.554) and SD (r=0.537). Bland-Altman analysis revealed that GPET overestimated both BW and SD (20.5° and 9.5°, respectively). In addition, the BW and SD measured by GPET were still overestimated after subgroup analysis. Between GPET and GSPECT, multivariate regression analysis revealed that total perfusion defects were related to the difference in BW measurement (P<0.001), and mismatch was associated with the difference in SD measurement (P<0.01). Conclusions: In patients with infarction, GPET moderately correlated with GSPECT in assessing LV dyssynchrony. GPET overestimated both BW and SD, so these analyses should not be interchangeable in individual patients.