Imaging of Integrin αβ Expression Using Ga-RGD Positron Emission Tomography in Pediatric Cerebral Infarct

Enhanced expression of integrin α v β 3 is commonly used as a biomarker for angiogenesis, which is one of the key pathophysiologic processes in cerebral infarct. Integrin α v β 3 can be imaged with arginine-glycine-aspartic acid (RGD) peptide agents. In this study, characteristics of positron emission tomography (PET) using a 68 Ga-labeled RGD were investigated in pediatric cerebral infarct. Pediatric patients with moyamoya disease underwent 68 Ga-RGD PET in a research protocol for neovascularization evaluation. In these patients, 17 cerebral infarct lesions of 10 patients were included in the analysis. On 68 Ga-RGD PET, the infarct lesion to contralateral brain ratio (LCR) of the infarct lesion was measured and analyzed with regard to postinfarct time interval (PTI) and perfusion single-photon emission computed tomography (SPECT) findings. An increase in 68 Ga-RGD uptake was observed in cerebral infarct, particularly in recent lesions. The LCR was significantly higher in the recent than in the chronic lesions, and a significant correlation existed between the LCR and PTI. Additionally, the LCR was significantly higher in the lesions with hyperperfusion on SPECT. This study, as the first human study using an RGD agent for in vivo cerebral infarct imaging, demonstrated that 68 Ga-RGD PET has a potential for molecular imaging of integrin α v β 3 expression in cerebral infarct as a biomarker of angiogenesis.