Current Advances in the Diagnostic Imaging of Atherosclerosis: Insights into the Pathophysiology of Vulnerable Plaque

Abstract

Atherosclerosis is a lipoprotein-driven inflammatory disorder leading to a plaque formation at specific sites of the arterial tree. After decades of slow progression, atherosclerotic plaque rupture and formation of thrombi are the major factors responsible for the development of acute coronary syndromes (ACSs). In this regard, the detection of high-risk (vulnerable) plaques is an ultimate goal in the management of atherosclerosis and cardiovascular diseases (CVDs). Vulnerable plaques have specific morphological features that make their detection possible, hence allowing for identification of high-risk patients and the tailoring of therapy. Plaque ruptures predominantly occur amongst lesions characterized as thin-cap fibroatheromas (TCFA). Plaques without a rupture, such as plaque erosions, are also thrombi-forming lesions on the most frequent pathological intimal thickening or fibroatheromas. Many attempts to comprehensively identify vulnerable plaque constituents with different invasive and non-invasive imaging technologies have been made. In this review, advantages and limitations of invasive and non-invasive imaging modalities currently available for the identification of plaque components and morphologic features associated with plaque vulnerability, as well as their clinical diagnostic and prognostic value, were discussed. Int. J. Mol. Sci. 2020, 21, 2992 2 of 26 by the low and oscillatory endothelial shear stress [3]. According to the current understanding, lesion development involves lipid accumulation in the arterial intima, resulting in foam cell formation, a local inflammatory response, and migration and proliferation of several cell types, including macrophages, smooth muscle cells (SMCs), lymphocytes, neutrophils, and dendritic cells that play a pivotal role in its progression. Lipid accumulation is a key event in the formation of the atherosclerotic lesion, and it is determined by different classes of lipoproteins [4]. Atherosclerotic plaque tends to develop early in life [5], progressing with age; however, the progression rate is not completely predictable and varies among individuals. In general, it undergoes a prolonged asymptomatic phase (lasting many years or several decades) until the manifestation of the first clinical symptoms often at the later stages of atherosclerosis. The mechanisms of plaque progression encompass SMC apoptosis, matrix synthesis, angiogenesis, arterial remodeling, fibrous cap rupture, and thrombosis, followed by necrosis and calcification. The most acute cardiovascular events are triggered by the rupture; erosion; or, the least common, calcified nodule, the vulnerable plaque phenotypes, followed by coronary thrombosis. Ruptured lesions are responsible for the majority (73%) of all ACSs [6]. In addition, the underlying mechanism of sudden coronary death from thrombi was found from plaque erosions, in 30%-35% of cases, and rarely from calcified nodules, in 2%-7% of cases [7].The biological features of two major classes of high-risk (vulnerable) plaques, such as rupture-pron...

Strong association of glaucoma with atherosclerosis

“…Atherosclerosis is a lipoprotein-driven inflammatory disorder leading to plaque formation at specific sites of the arterial tree, computed tomographic coronary angiography is a noninvasive imaging alternative that enables accurate evaluation of the luminal and outer vessel wall dimensions, high-risk plaque burden and morphology, and remodeling pattern 14 . The CT criteria for diagnosis of AS is that there are plaques in the vessels with lumen narrowing.…”

Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging

“…Even though NIRS imaging provides a reliable and quantitative assessment of lipid-core plaques, it cannot assess lumen size, vessel wall dimension and plaque burden. In addition, it cannot provide information about the depth of the lipid component into the vessel wall [21].…”

“…To address this challenge, multi-modality intravascular imaging that combines different imaging techniques with complementary strengths into advanced images has been proposed and developed. Since the multimodal intravascular imaging technology has been reviewed extensively by many researchers [21,[181][182][183][184], in this section, we concentrate on the reported applications of IVUS-based dual-modality intravascular imaging including IVUS-OCT, IVUS-NIRS, IVUS-IVPA, IVUS-NIRF, IVUS-TRFS (FLIM) and tri-modality intravascular imaging including IVUS-OCT-NIRF and IVUS-OCT-IVPA. Representative dual-modality and tri-modality intravascular imaging systems are demonstrated in Figure 10.…”

“…Over the past two decades, various invasive and non-invasive imaging modalities have been introduced and validated to comprehensively identify the structure and composition of atherosclerotic plaques [21]. The invasive imaging modalities include intravascular ultrasound (IVUS) imaging, optical coherence tomography (OCT), near-infrared spectroscopic (NIRS) imaging, intravascular photoacoustic (IVPA) imaging, near infrared fluorescence (NIRF) imaging, time resolved fluorescence spectroscopic (TRFS) imaging and fluorescence life-time imaging (FLIM).…”

Morphological Features of the Structure of Unstable Atherosclerotic Plates of the Coronary Heart Arteries

“…Важно подчеркнуть, что понятие «нестабильность АБ» является неоднозначным, подразумевающим, в том числе, нарушение гемодинамической функции коронарной артерии [6][7][8].…”