Clinical Application Of Radionuclide Imaging In Cardiovascular Disease

PartⅠPhase analysis by gated F-18FDG PET/CT for left ventricular dyssynchrony assessment:comparison with gated Tc-99m sestamibi SPECTPurpose:To investigate the value of gated F-18FDG PET/CT on left ventricular (LV) dyssynchrony assessment in comparison with gated Tc-99m sestamibi SPECT in patients with coronary artery disease (CAD).Methods:The data of100consecutive CAD patients who underwent both gated myocardial Tc-99m sestamibi SPECT and F-18FDG PET/CT imaging were analyzed. Phase standard deviation (SD) and histogram bandwidth (BW) were derived from phase analysis using Cedars software package. The correlation and agreement of SD and BW between Tc-99m sestamibi SPECT and F-18FDG PET/CT were examined. Myocardial viability and the site of latest activation assessed by the two imaging methods were compared as well.Results:A moderate correlation for SD (r=0.58, p<0.0001) and BW (r=0.60, p<0.0001) was found between gated SPECT and gated F-18FDG PET/CT. Bland-Altman analysis revealed an overestimation of SD and BW (6.4°±14.3°and22.0°±■46.8°) by gated F-18FDG PET/CT. Multivariate logistic regression analysis identified that significant LV remodeling on SPECT imaging, LV functional parameters and F-18FDG uptake ratio of myocardium to blood pool (SUVM/B) were associated with the overestimation. Myocardial SPECT and F-18FDG PET/CT had a67.1%identity in determining the latest activation site and5.2%more viable myocardium was detected by18F-FDG PET/CT than SPECT.Conclusion:Gated F-18FDG PET/CT moderately correlated with gated Tc-99m sestamibi SPECT in assessing LV dyssynchrony. Gated F-18FDG PET/CT phase analysis should be cautiously applied in CAD patients with significant LV remodeling on SPECT imaging, severe LV functional impairment or poor myocardial F-18FDG uptake. Part ⅡPrognostic significance of left ventricular dyssynchrony by phase analysis of gated SPECT in medically treated patients with dilated cardiomyopathyPurpose:The study aimed to investigate the value of clinical variables and rest gated single photon emission computed tomography (SPECT) in predicting cardiac deaths in medically treated dilated cardiomyopathy (DCM) patients.Methods:This is a retrospective study. Fifty-six consecutive hospitalized DCM patients who underwent rest gated SPECT myocardial perfusion imaging (MPI) were initially recruited. Patients were further excluded for receiving heart transplantation, cardiac resynchronization treatment (CRT) and non-cardiac death during follow-up. The remaining48medically treated DCM patients were selected into the final analysis. Phase analysis of gated SPECT was conducted to identify LV dyssynchrony. Cardiac death during follow-up was considered as the only endpoint. Univariate and multivariate Cox proportional hazards regression analysis were performed to identify the independent predictors of cardiac death. Kaplan-Meier cumulative survival analysis with stratification was performed, and survival curves were compared by Log-rank test.Results:The mean age was47.5±15.8years (range,15-76y) and85.4%were men. The mean LV ejection fraction (LVEF) was22.2±7.7%. During the follow-up period (22.7±5.1months),12(25.0%) cardiac deaths occurred. Compared to survivors, patients with cardiac death had lower body mass index (BMI, P=0.010), higher percent of prolonged QRS duration (QRSD, P=0.043) and severe LV dyssynchrony (P=0.002). Multivariate Cox analysis demonstrated that severe LV dyssynchrony (hazard ratio=9.607,95%confidential interval,95%CI2.064-44.713, P=0.004) and BMI (hazard ratio=0.851,95%CI0.732-0.989, P=0.036) were predictive of cardiac death.Conclusion:Left ventricular dyssynchrony assessed by phase analysis of gated SPECT and BMI are predictive of cardiac death in medically treated DCM patients. Part IIIGated F-18FDG PET for assessment of left ventricular volumes and ejection fraction using QGS and4D-MSPECT in patients with heart failure:comparison with cardiac MRIPurpose:Ventricular function is a powerful predictor of survival in patients with heart failure (HF). However, so far, studies on gated F-18FDG PET for assessment of the cardiac function are fairly rare. The aim of this study is to prospectively compare gated F-18FDG PET and cardiac MRI for assessment of ventricular volume and ejection fraction (EF) in patients with HF.Methods:Eighty-nine patients with diagnosed HF who underwent both gated F-18FDG PET/CT and cardiac MRI within3days were included. Left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and EF were obtained from gated F-18FDG PET/CT using Quantitative Gated SPECT (QGS) and4D-MSPECT software, respectively.Results:LV EDV and ESV measured by QGS were significantly lower than those of cardiac MRI (both P<0.0001), whereas the corresponding values of LV EDV for4D-MSPECT showed no statistical significance (P=0.595) and LV ESV showed an underestimation in borderline significance in comparison with cardiac MRI (P=0.047, respectively). LV EF measured by QGS showed no statistical significance in comparison with cardiac MRI (P=0.95) whereas the corresponding values for4D-MSPECT were lower than those of cardiac MRI (P<0.0001). The correlations of LV EDV, ESV and EF between gated F-18FDG PET/CT and cardiac MRI were excellent for both QGS (R=0.92,0.92and0.76, respectively) and4D-MSPECT (R=0.93,0.94and0.75, respectively). Bland-Altman analysis revealed significant systemic error that LV EDV (-27.9±37.0mL; bias significantly different from0, P=0.004) and ESV (-18.6±33.8mL; bias significantly different from0,P=0.01) were underestimated by QGS.Conclusion:For patients with HF, despite gated F-18FDG PET/CT correlated well with cardiac MRI in assessment of ventricular volumes and EF, variability between the two techniques did exist. Hence, in comparison with cardiac MRI, the two imaging techniques should not be used interchangeably and LV volumes and LV EF by gated F-18FDG PET/CT should be cautiously interpreted.