Evaluation of Plaque Characteristics and Inflammation Using Magnetic Resonance Imaging

Abstract

Atherosclerosis is an inflammatory disease of large and medium-sized arteries, characterized by the growth of atherosclerotic lesions (plaques). These plaques often develop at inner curvatures of arteries, branchpoints, and bifurcations, where the endothelial wall shear stress is low and oscillatory. In conjunction with other processes such as lipid deposition, biomechanical factors lead to local vascular inflammation and plaque growth. There is also evidence that low and oscillatory shear stress contribute to arterial remodeling, entailing a loss in arterial elasticity and, therefore, an increased pulse-wave velocity. Although altered shear stress profiles, elasticity and inflammation are closely intertwined and critical for plaque growth, preclinical and clinical investigations for atherosclerosis mostly focus on the investigation of one of these parameters only due to the experimental limitations. However, cardiovascular magnetic resonance imaging (MRI) has been demonstrated to be a potent tool which can be used to provide insights into a large range of biological parameters in one experimental session. It enables the evaluation of the dynamic process of atherosclerotic lesion formation without the need for harmful radiation. Flow-sensitive MRI provides the assessment of hemodynamic parameters such as wall shear stress and pulse wave velocity which may replace invasive and radiation-based techniques for imaging of the vascular function and the characterization of early plaque development. In combination with inflammation imaging, the analyses and correlations of these parameters could not only significantly advance basic preclinical investigations of atherosclerotic lesion formation and progression, but also the diagnostic clinical evaluation for early identification of high-risk plaques, which are prone to rupture. In this review, we summarize the key applications of magnetic resonance imaging for the evaluation of plaque characteristics through flow sensitive and morphological measurements. The simultaneous measurements of functional and structural parameters will further preclinical research on atherosclerosis and has the potential to fundamentally improve the detection of inflammation and vulnerable plaques in patients.

Detecting vulnerable carotid plaque and its component characteristics: Progress in related imaging techniques

“…In a multicenter prospective cohort study of patients with carotid stenosis and recent stroke/transient ischemic attack, Kelly et al showed that plaque inflammation associated 18 F-FDG uptake independently predicted future recurrent stroke after PET ( 33 ). Similarly, in a PET study using 18 F-fluorcholine ( 18 F-FCH), histological analysis of carotid endarterectomy specimens revealed a strong correlation between the uptake of the tracer and the macrophage infiltration ( 34 , 35 ). Other examples of PET include 68 Ga-DOTATATE PET ( 36 ), used in the expression of somatostatin receptor imaging, as the tool of detecting artery inflammation, or CD80-targeting PET Tracers ( 37 ).…”

Positron emission tomography and its role in the assessment of vulnerable plaques in comparison to other imaging modalities

“…The initiation of atherosclerosis depends on the accumulation of small lipoprotein particles in the intima, particularly at sites of hemodynamic strain, caused by the intake of diets high in cholesterol and saturated fats ( 1 , 7 , 8 ). These particles are susceptible to oxidative stress, which promotes the attraction of leukocytes, particularly phagocytes.…”

Advanced targeted nanomedicines for vulnerable atherosclerosis plaque imaging and their potential clinical implications

“…Atherosclerotic plaques are regarded as a gradual buildup of a heterogeneous collection of lipids, fibrous tissue, inflammatory cells, and other materials in the arterial wall. This process involves a series of specific cellular and molecular events in the arterial lesions, which can serve as local targeting epitopes for nanoparticles ( Shah, 2009 ; Magnus et al, 2019 ), including endothelial cell activation ( Andelovic et al, 2021 ), inflammation ( Soehnlein and Libby, 2021 ), angiogenesis ( Camaré et al, 2017 ), apoptosis ( van Tilborg et al, 2010 ), platelet activation, and thrombus ( Sanz and Fayad, 2008 ) ( Scheme 1 ).…”