Abstract
1094
Objectives Ga-68-RGD is a recently introduced molecular imaging agent for angiogenesis imaging, labeled with a generator-produced radioisotope Ga-68. We evaluated the feasibility and characteristics of 68Ga-RGD PET as myocardial infarction (MI) imaging.
Methods 7-week old six Sprague-Dawley rats were used as subjects. Permanent left anterior descending artery (LAD) occlusion surgery was performed on three rats as MI group. The others underwent sham operation as control group. Ga-68-RGD PET imaging was performed on 1 d, 1 wk and 2 wk after operation for all subjects. Myocardial perfusion PET using Ga-68-BAPEN and myocardial FDG PET were also obtained as perfusion and metabolism imaging to confirm MI. Quantitative analysis were performed by measuring lesion-to-normal ratio (LNR) by drawing region of interest on LAD territory and normal myocardium on 68Ga-RGD images.
Results In MI group, increased Ga-68-RGD uptakes were observed in LAD territory of myocardium from 1 d to 2 wk after surgery. In this territory, perfusion and metabolic defects were confirmed by 68Ga-BAPEN and FDG PET images on visual estimation. On the contrary, no significant uptake abnormality of Ga-68-RGD, Ga-68-BAPEN and FDG was seen in control group. In quantitative analysis, LNR of occlusion group was significantly higher than that of control group at all the time points, and gradually decreased with time: 1.86±0.05 vs. 1.38±0.08 at 1 d, 1.83±0.10 vs. 1.24±0.36 at 1 wk, 1.65±0.18 vs. 1.17±0.19 at 2 wk.
Conclusions Ga-68-RGD PET is feasible for MI imaging which imply angiogenesis and possible fibrosis or regeneration. Pathophysiological significance and prognostic value of Ga-68-RGD PET require further investigation