Angiogenesis imaging in myocardial infarction using ⁶⁸Ga-NOTA- RGD PET: Characterization and application to therapeutic efficacy monitoring in rats

OBJECTIVE: ⁶⁸Ga-NOTA-RGD PET is a newly developed molecular imaging for angiogenesis. In this study, ⁶⁸Ga-NOTA-RGD PET was used to investigate imaging characteristics in a rat myocardial infarction (MI) model and to monitor the efficacy of an angiogenesis induction therapy. MATERIALS AND METHODS: ⁶⁸Ga-NOTA-RGD PET was performed serially in rats with MI or sham operation, and myocardial uptake was analyzed with respect to time duration and tissue characteristics. Subsequently, Ga-NOTA-RGD PET was serially performed for therapeutic efficacy monitoring in MI-induced rats, which were treated with basic fibroblast growth factor (bFGF) injection or saline injection. Image findings were compared with the final change in MI lesion. RESULTS: ⁶⁸Ga-NOTA-RGD uptake was significantly increased in MI lesion and gradually decreased over time. ⁶⁸Ga-NOTA-RGD uptake in the infarcted tissue corresponded with vascular endothelial growth factor expression and macrophage accumulation. In monitoring of therapeutic efficacy, the lesion uptake in the bFGF-injected group was significantly higher than that of the saline-injected and sham-operated groups on the first day. However, no significant differences were observed between bFGF and saline-injected groups at subsequent time points, corresponding to the final infarct size change. CONCLUSION: ⁶⁸Ga-NOTA-RGD PET would be a useful angiogenesis imaging modality in MI for assessment of pathophysiology or monitoring of therapeutic efficacy.