Comparison of the Cardiac MicroPET Images Obtained Using [(18)F]FPTP and [(13)N]NH3 in Rat Myocardial Infarction Models

The short half-life of current positron emission tomography (PET) cardiac tracers limits their widespread clinical use. We previously developed a (18)F-labeled phosphonium cation, [(18)F]FPTP, that demonstrated sharply defined myocardial defects in a corresponding infarcted myocardium. The aim of this study was to compare the image properties of PET scans obtained using [(18)F]FPTP with those obtained using [(13)N]NH3 in rat myocardial infarction models. Perfusion abnormality was analyzed in 17 segments of polar map images. The myocardium-to-liver and myocardium-to-lung ratios of [(18)F]FPTP were 10.48 and 2.65 times higher, respectively, than those of [(13)N]NH3 in images acquired 30 min after tracer injection. The myocardial defect size measured by [(18)F]FPTP correlated more closely with the hypoperfused area measured by quantitative 2,3,5-triphenyltetrazolium chloride staining (r = 0.89, P < 0.01) than did [(13)N]NH3 (r = 0.84, P < 0.01). [(18)F]FPTP might be useful as a replacement for the myocardial agent [(13)N]NH3 in cardiac PET/CT applications.