Abstract 313: A Novel Catheter-Based Radionuclide Imaging System to Characterize Atherosclerotic Plaque
Objectives: Atherosclerosis underlies coronary artery diseases—the leading cause of death in the United States and worldwide. In this study, we developed a novel catheter-based radionuclide imaging (CRI) system to image 18F-fluorodeoxyglucose (18F-FDG), a radionuclide, a marker of vascular inflammation, in murine carotid arteries and characterized the system for spatial resolution from multiple scintillating materials.
Methods: The catheter system includes 35 mm and 8 mm fixed focal length lenses, which are subsequently connected to a CMOS camera and fiber holder. The distal ferrule of an image bundle is terminated with a wide-angle lens. The novelty of this system is a scintillating balloon with a crystal tip in the front of the wide angle lens to image light from the decay of 18F-FDG emission signal. The scintillating balloon is fabricated from 1mL of silicone RTV catalyst mixed with 1 mL base and 50 mg/mL calcium fluoride doped with Europium (CaF2:Eu). To identify the optimal scintillating materials with respect to resolution, we calculated modulation transfer function (MTF) of Yttrium Aluminum Garnet doped with Cerium (YAG:Ce), anthracene, and CaF2:Eu phosphors using a thin line optical phantom (Fig. 1a-1b). Macrophage-rich FVB murine atherosclerotic carotid plaque model (n = 4) was used in ex vivo experiments. Confirmatory imaging was also performed by an external optical imaging system (IVIS-200).
Results: Analysis of the different phosphors (Fig 1b) showed that CaF2:Eu enabled the best resolution of 1.2μm. The CRI system visualized 18F-FDG in atherosclerotic plaques (Fig. 1d). The ligated left carotid (LR) artery exhibited 4.9х higher 18F-FDG signal intensity compared to the non-ligated right carotid (negative control) artery (2.6х104 ±1.4х103 vs. 5.4х103 ±1.3х103, A.U., p = 0.008) and confirmed with IVIS-200 (Fig. 1d).
Conclusions: This CRI system enables high-resolution and sensitive detection of 18F-FDG uptake by murine atherosclerotic plaques.
Author Disclosures: R. Zaman: None. H. Kosuge: None. C. Carpenter: None. G. Pratx: None. C. Sun: None. L. Xing: None. M. McConnell: Other; Modest; Stanford Department of Medicine has a MRI research agreement with GE Healthcare.
This research has received full or partial funding support from the American Heart Association.
- © 2014 by American Heart Association, Inc.