Imaging Atherosclerotic Plaque Inflammation by Fluorodeoxyglucose With Positron Emission Tomography

Abstract

Inflammation is a determinant of atherosclerotic plaque rupture, the event leading to most myocardial infarctions and strokes. Although conventional imaging techniques identify the site and severity of luminal stenosis, the inflammatory status of the plaque is not addressed. Positron emission tomography imaging of atherosclerosis using the metabolic marker fluorodeoxyglucose allows quantification of arterial inflammation across multiple vessels. This review sets out the background and current and potential future applications of this emerging biomarker of cardiovascular risk, along with its limitations.

The Immune System in Stroke: Clinical Challenges and Their Translation to Experimental Research

“…In patients with symptomatic carotid atherosclerosis, 18 FDG uptake correlates with macrophage-rich areas of plaque, matrix metalloproteinase-9 (MMP-9) expression (Rudd et al 2010;Tawakol et al 2006;Graebe et al 2009), distal microembolic signals and early recurrence of cerebrovascular events (Moustafa et al 2010;Marnane et al 2012).…”

Targeting activated macrophages to identify the vulnerable atherosclerotic plaque

“…5 Subsequent papers have explored the value of 18 F-FDG plaque imaging as a noninvasive biomarker to follow plaque inflammation over time and assess plaque stabilizing drug efficacy. [6][7][8][9] Myocardial dependence on availability of exogenous glucose as a metabolic substrate makes visualizing the coronaries difficult to impossible with 18 F-FDG despite dietary manipulations to switch myocardial substrate availability to fatty acids. In addition to the coronary circulation, other limitations to 18 F-FDG imaging in atherosclerosis include spillover from residual blood pool activity into the arterial walls, dependence of uptake on blood glucose levels that can be problematic in diabetics, and experimental data showing that hypoxia stimulates 18 F-FDG uptake in macrophages while proinflammatory cytokines stimulate uptake of 18 F-FDG in endothelial cells and smooth muscle cells.…”

Predicting Aortic Aneurysm Expansion by PET

“…18 F-FDG PET/CT is commonly used to identify metabolically active cells for cancer diagnosis and risk stratification. The technique can be modified slightly (by increasing the 18 F-FDG circulation time) for application in arterial disease, such as atherosclerosis (20)(21)(22) and vasculitis (23), as a surrogate marker of inflammation. It is believed that the arterial 18 F-FDG signal reflects glucose accumulation, predominantly by macrophages (24) and other plaque inflammatory cells (25), which can be amplified by hypoxia (26).…”