Sodium [¹⁸F]fluoride PET/CT in myocardial infarction.

Abstract

Sodium [(18)F]fluoride (Na[(18)F]F) positron emission tomography with integrated computed tomography (PET/CT) has not been used for imaging myocardial infarction (MI). Here, we aimed to investigate the Na[(18)F]F PET/CT features of MI in a rat model. MI was induced by coronary artery ligation in 8-week-old male Spraque-Dawley rats (300 ± 10 g) and confirmed by triphenyl tetrazolium chloride (TTC) staining. Na[(18)F]F PET/CT images were obtained using an animal-dedicated PET/CT scanner (NanoPET/CT, Mediso) in vivo and ex vivo. Uptake of Na[(18)F]F was quantitated using the standardized uptake value (SUV). Myocardial apoptosis was evaluated using histone-1 targeted peptide (ApoPep-1) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, while calcium accumulation was investigated using von Kossa's staining. Na[(18)F]F PET/CT was compared with (99m)Tc-methoxyisobutylisonitrile (MIBI) or (99m)Tc-hydroxymethylenediphosphonate (HMDP) single photon emission computed tomography/computed tomography (SPECT/CT) in rats with day 1 MI. The rats showed strong Na[(18)F]F uptake both in vivo and ex vivo; the maximal uptake occurred 1 day after MI (SUV ratio of infarct to lung = 4.56 ± 0.74, n = 7, P = 0.0183 vs the control). The Na[(18)F]F uptake area perfectly matched the apoptotic area, determined by ApoPep-1 uptake and TUNEL assay. However, calcification, assessed by von Kossa's staining, was absent in the infarct. Na[(18)F]F PET/CT showed an increased uptake at the perfusion deficit area in [(99m)Tc]MIBI SPECT/CT and an equivalent signal to [(99m)Tc]HMDP SPECT/CT in rats with day 1 MI. Na[(18)F]F PET/CT is a promising hot-spot imaging modality for MI.