Objective: In this study, the feasibility and kinetic characteristics of the (68)Ga-NOTA-RGD, a recently developed RGD peptide agent, were investigated for atherosclerosis imaging in comparison with (18)FDG.
Methods: ApoE(-/-) mice were fed a high-fat diet for more than 20 weeks. To evaluate the feasibility, tissue uptakes of (68)Ga-NOTA-RGD and (18)FDG in the major organs were measured and compared between ApoE(-/-) and control mice. Animal PET imaging was also performed and relative uptake values in the thoracic aorta were compared between ApoE(-/-) and control mice. In humans, the kinetic characteristics and feasibility of (68)Ga-NOTA-RGD PET were assessed in 4 patients with known coronary artery disease.
Results: In the tissue uptake study, the thoracic aorta showed higher uptake in ApoE(-/-) than in control mice with both (68)Ga-NOTA-RGD and (18)FDG (P < 0.001). On PET scans, the relative uptake values of the thoracic aorta were significantly higher in ApoE(-/-) with both (68)Ga-NOTA-RGD (P = 0.024) and (18)FDG (P = 0.038). In human PET, the appropriateness of reversible binding model and Logan plotting was clearly demonstrated. The aorta-to-jugular ratios were measured up to 1.25 and showed a tendency to correlate with the serum high-sensitivity C-reactive protein level (r = 0.899, P = 0.102).
Conclusions: (68)Ga-NOTA-RGD has potential as an in vivo atherosclerosis imaging agent. However, the lower imaging contrast and sensitivity of (68)Ga-NOTA-RGD PET compared with (18)FDG PET may be a limitation for clinical application.