Abstract 12853: [ 64 Cu]Cu-DOTATATE is Superior to [ 68 Ga]Ga-NODAGA-E[c(RGDyK)]2 (RGD) PET/CT Imaging In Detection and Quantification of Atherosclerosis: A Retrospective Analysis of a Phase 2 Trial Cohort

Abstract

Introduction: Inflammation and angiogenesis are central to development of atherosclerosis. [ 64 Cu]Cu-DOTATATE and [ 68 Ga]Ga-NODAGA-E[c(RGDyK)]2 (RGD) are PET tracers that can non-invasively visualize somatostatin receptor subtype 2 (SSTR 2 ) and α v β 3 integrin expression that represent inflammation and angiogenesis respectively. Hypothesis: Whether an imaging tracer of inflammation can be compared with a tracer of angiogenesis for detection and quantification of the atherosclerotic process in patients from a Phase II cancer trial cohort. Methods: A cohort of patients from Phase II trial were divided in three groups as controls (N=7), at risk (N=6) & diseased (N=7). PET/CT scans with two different tracers were performed in all subjects. The scans were retrospectively analyzed, and tracer uptake (mean of maximum target-to-background ratios (mTBRmax)) were determined in 6 arterial segments. In addition, plaques from patients (N=7) undergoing carotid endarterectomy (CEA) were studied with autoradiography and immunohistochemistry. Results: [ 64 Cu]Cu-DOTATATE uptake in the disease group was significantly higher compared to the control group in the abdominal aorta (4.4 vs 2.1, p=0.02), thoracic aorta (3.0 vs 2.2, p=0.02), aortic arch (2.8 vs 2.2, p=0.03), left carotid artery (2.2 vs 1.3, p=0.02) and the average of all six aortic segments (2.7 vs 2.0, p=0.01) whereas all aortic segments in the disease group showed a higher but a non-significant difference compared to the control group with RGD uptake. A moderate correlation was found between the mean aortic uptake of [ 64 Cu]Cu-DOTATATE & RGD (r=0.41, p=0.01) in patients from the disease group. SSTR 2 and α v β 3 expression was confirmed on ex vivo plaques along with tracer binding. Conclusions: An in vivo imaging marker of inflammation was superior to a marker of angiogenesis in discriminating levels of atherosclerosis. The two markers were weakly correlated in patients with known cardiovascular disease.