Integrin αvβ3 is overexpressed in both neovasculature and glioma cells. We aimed to evaluate (68)gallium-BNOTA-PRGD2 ((68)Ga-PRGD2) as a new reagent for noninvasive integrin αvβ3 imaging in glioma patients. With informed consent, 12 patients with suspicious brain glioma, as diagnosed by enhanced magnetic resonance imaging (MRI) scanning, were enrolled to undergo (68)Ga-PRGD2 PET/CT and (18)F-FDG PET/CT scans before surgery. The preoperative images were compared and correlated with the pathologically determined WHO grade. Next, the expression of integrin αvβ3, CD34, and Ki-67 were determined by immunohistochemical staining of the resected brain tumor tissue. Our findings demonstrated that (68)Ga-PRGD2 specifically accumulated in the brain tumors that were rich of integrin αvβ3 and other neovasculature markers, but not in the brain parenchyma other than the choroid plexus. Therefore, (68)Ga-PRGD2 PET/CT was able to evaluate the glioma demarcation more specifically than (18)F-FDG PET/CT. The maximum standardized uptake values (SUVmax) of (68)Ga-PRGD2, rather than those of (18)F-FDG, were significantly correlated with the glioma grading. The maximum tumor-to-brain ratios (TBRmax) of both tracers were significantly correlated with glioma grading, whereas (68)Ga-PRGD2 seemed to be more superior to (18)F-FDG in differentiating high-grade glioma (HGG) from low-grade glioma (LGG). Moreover, (68)Ga-PRGD2 PET/CT showed different accumulation patterns for HGG of WHO grades III and IV. This is the first noninvasive integrin imaging study, to the best of our knowledge, conducted in preoperative patients with different grades of glioma, and it preliminarily indicated the effectiveness of this novel method for evaluating glioma grading and demarcation.
Keywords: 68Ga; PET/CT; glioma; integrin αvβ3.