title: Indocyanine green enables near-infrared fluorescence imaging of lipid-rich, inflamed atherosclerotic plaques.
abstract: New high-resolution molecular and structural imaging strategies are needed to visualize high-risk plaques that are likely to cause acute myocardial infarction, because current diagnostic methods do not reliably identify at-risk subjects. Although molecular imaging agents are available for low-resolution detection of atherosclerosis in large arteries, a lack of imaging agents coupled to high-resolution modalities has limited molecular imaging of atherosclerosis in the smaller coronary arteries. Here, we have demonstrated that indocyanine green (ICG), a Food and Drug Administration-approved near-infrared fluorescence (NIRF)-emitting compound, targets atheromas within 20 min of injection and provides sufficient signal enhancement for in vivo detection of lipid-rich, inflamed, coronary-sized plaques in atherosclerotic rabbits. In vivo NIRF sensing was achieved with an intravascular wire in the aorta, a vessel of comparable caliber to human coronary arteries. Ex vivo fluorescence reflectance imaging showed high plaque target-to-background ratios in atheroma-bearing rabbits injected with ICG compared to atheroma-bearing rabbits injected with saline. In vitro studies using human macrophages established that ICG preferentially targets lipid-loaded macrophages. In an early clinical study of human atheroma specimens from four patients, we found that ICG colocalized with plaque macrophages and lipids. The atheroma-targeting capability of ICG has the potential to accelerate the clinical development of NIRF molecular imaging of high-risk plaques in humans.
authors: Center for Molecular Imaging Research, Massachusetts General Hospital, Boston, MA 02114, USA.
authors: Claudio
authors: C
authors: Vinegoni
authors: Ion
authors: I
authors: Botnaru
authors: Elena
authors: E
authors: Aikawa
authors: Marcella A
authors: MA
authors: Calfon
authors: Yoshiko
authors: Y
authors: Iwamoto
authors: Eduardo J
authors: EJ
authors: Folco
authors: Vasilis
authors: V
authors: Ntziachristos
authors: Ralph
authors: R
authors: Weissleder
authors: Peter
authors: P
authors: Libby
authors: Farouc A
authors: FA
authors: Jaffer
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