Comparison of Somatostatin Receptor 2-Targeting PET Tracers in the Detection of Mouse Atherosclerotic Plaques

Purpose Rupture-prone atherosclerotic plaques are characterized by accumulation of macrophages, which have shown to express somatostatin type 2 receptors. We aimed to investigate whether somatostatin receptor-targeting positron emission tomography (PET) tracers, [ 68 Ga]DOTANOC, [ 18 F]FDR-NOC, and [ 68 Ga]DOTATATE, can detect inflamed atherosclerotic plaques. Procedures Atherosclerotic IGF-II/LDLR −/− ApoB 100/100 mice were studied in vivo and ex vivo for tracer uptake into atherosclerotic plaques. Furthermore, [ 68 Ga]DOTANOC and [ 68 Ga]DOTATATE were compared in a head-to-head setting for in vivo PET/X-ray computed tomography (CT) imaging characteristics. Results Ex vivo uptake of [ 68 Ga]DOTANOC and [ 68 Ga]DOTATATE in the aorta was higher in atherosclerotic mice compared to control C57Bl/6N mice, while the aortic uptake of [ 18 F]FDR-NOC showed no genotype difference. Unlike [ 18 F]FDR-NOC, [ 68 Ga]DOTANOC and [ 68 Ga]DOTATATE showed preferential binding to atherosclerotic plaques with plaque-to-wall ratio of 1.7 ± 0.3 and 2.1 ± 0.5, respectively. However, the aortic uptake and aorta-to-blood ratio of [ 68 Ga]DOTANOC were higher compared to [ 68 Ga]DOTATATE in in vivo PET/CT imaging. Conclusion Our results demonstrate superior applicability for [ 68 Ga]DOTANOC and [ 68 Ga]DOTATATE in the detection of atherosclerotic plaques compared to [ 18 F]FDR-NOC.