Gated cardiac 13N-NH3 PET for assessment of left ventricular volumes, mass, and ejection fraction: comparison with electrocardiography-gated 18F-FDG PET.
The purpose of this study was to evaluate myocardial electrocardiography (ECG)-gated 13N-ammonia (13N-NH3) PET for the assessment of cardiac end-diastolic volume (EDV), cardiac end-systolic volume (ESV), left ventricular (LV) myocardial mass (LVMM), and LV ejection fraction (LVEF) with gated 18F-FDG PET as a reference method.


METHODS
ECG-gated 13N-NH3 and 18F-FDG scans were performed for 27 patients (23 men and 4 women; mean+/-SD age, 55+/-15 y) for the evaluation of myocardial perfusion and viability. For both 13N-NH3 and 18F-FDG studies, a model-based image analysis tool was used to estimate endocardial and epicardial borders of the left ventricle on a set of short-axis images and to calculate values for EDV, ESV, LVEF, and LVMM.


RESULTS
The LV volumes determined by 13N-NH3 and 18F-FDG were 108+/-60 mL and 106+/-63 mL for ESV and 175+/-71 mL and 169+/-73 mL for EDV, respectively. The LVEFs determined by 13N-NH3 and 18F-FDG were 42%+/-13% and 41%+/-13%, respectively. The LVMMs determined by 13N-NH3 and 18F-FDG were 179+/-40 g and 183+/-43 g, respectively. All P values were not significant, as determined by paired t tests. A significant correlation was observed between 13N-NH3 imaging and 18F-FDG imaging for the calculation of ESV (r=0.97, SEE=14.1, P<0.0001), EDV (r=0.98, SEE=15.4, P<0.0001), LVEF (r=0.9, SEE=5.6, P<0.0001), and LVMM (r=0.93, SEE=15.5, P<0.0001).


CONCLUSIONS
Model-based analysis of ECG-gated 13N-NH3 PET images is accurate in determining LV volumes, LVMM, and LVEF. Therefore, ECG-gated 13N-NH3 can be used for the simultaneous assessment of myocardial perfusion, LV geometry, and contractile function.
Khorsand
Aliasghar
A
Department of Cardiology, Medical University of Vienna, Vienna, Austria. aliasghar.khorsand@meduniwien.ac.at
Graf
Senta
S
Eidherr
Harald
H
Wadsak
Wolfgang
W
Kletter
Kurt
K
Sochor
Heinz
H
Schuster
Ernst
E
Porenta
Gerold
G
D000328:Adult; D000368:Aged; D000641:Ammonia; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000473:pathology; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology*; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009590:Nitrogen Radioisotopes; D049268:Positron-Emission Tomography / Q000379:methods*; D012044:Regression Analysis; D013318:Stroke Volume; D013997:Time Factors
D009590:Nitrogen Radioisotopes; D019788:Fluorodeoxyglucose F18; D000641:Ammonia