Abstract 12212: Atherosclerotic Plaque Detection With a Fluorescence/Radionuclide Intravascular Imaging System for 18F-FDG and 6-NBDG
Objectives: Atherosclerosis is a progressive inflammatory condition that underlies coronary artery disease (CAD)—the leading cause of death in the USA. Thus, the overarching goal of this study includes (1) optimizing a dual-modality catheter-based intravascular imaging system that can visualize 18F-FDG and fluorescent glucose probes, (2) validating the system and quantifying sensitivity on ex vivo plaques.
Methods: A novel design implements a flexible fiber-optic catheter for both a diffuse optical fluorescence imaging system for fluorescent probes and a radioluminescence imaging system with a scintillator tip for radionuclide probes. The system includes an emission filter wheel placed between 35 mm and 8 mm fixed focal length lenses, which were subsequently connected to a CMOS camera and fiber holder, respectively. Both 18F-fluorodeoxyglucose (18F-FDG) and 6-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-6-Deoxyglucose (6-NBDG), radioluminescence and fluorescent glucose analogs, respectively, were studied. Mouse macrophage cells (RAW264.7) and murine macrophage-rich atherosclerotic carotid plaques were used for in vitro and ex vivo experiments, respectively. Confirmatory optical imaging was also performed (by IVIS-200).
Results: Our imaging system was able to successfully visualize both fluorescent and radioluminescent probes in macrophages and in atherosclerotic plaques.For 18F-FDG, the ligated left carotid artery exhibited 4.9х higher radioluminescence signals intensity compared to the non-ligated (negative control) right carotid artery (2.6х104 vs. 5.4х103 A.U., p = 0.008). Similarly, for 6-NBDG, the ligated left carotid artery emitted 4.3х brighter fluorescent signals than the control right carotid artery (1.6х102 vs. 3.8х101 A.U., p = 0.002). The higher uptake of both 18F-FDG and 6-NBDG in ligated left carotids was confirmed with the IVIS-200 system, with 2.5[[Unable to Display Character: –]]6.3х higher signal (p≤0.006 vs. right carotids).
Conclusions: This dual-modality catheter-based imaging systemwas sensitive to both 18F-FDG and 6-NBDG molecular probes taken up by murine atherosclerotic plaques. Both in vitro and ex vivo studies show that 6-NBDG is a promising fluorescent probe for detecting macrophage-rich atherosclerotic plaques.
- © 2013 by American Heart Association, Inc.