Assessment of Plaque Composition by Intravascular Ultrasound and Near-Infrared Spectroscopy

Abstract

Atherosclerosis is the main cause of coronary artery disease (CAD), which is today the leading cause of death worldwide and will continue to be the first in the world in 2030. Vulnerable coronary plaques are usually characterized by a high content of necrotic core, a thin inflamed fibrous cap (intense accumulation of macrophages) and scarce presence of smooth muscle cells. None of these characteristics can be estimated by coronary angiography, which on the contrary underestimates the magnitude of atherosclerotic burden, particularly in earlier stage disease when positive vascular remodeling may allow "normal" lumen caliber despite substantial vascular wall plaque. The recognition of the ubiquity of substantial but non-flow limiting lesions that may be at high risk for subsequent plaque rupture has resulted in a paradigm shift in thinking about the pathophysiology of CAD, with the focus no longer solely on the degree of arterial luminal narrowing. This growing need for more information about coronary atherosclerosis in order to identify patients and lesions at risk for complications during PCI and for future adverse cardiac events has been the primary impetus for the development of novel intracoronary imaging methods able to detect plaque composition, in particular presence of a necrotic core/lipid pool, such as intravascular ultrasound virtual histology and near-infrared spectroscopy. These imaging technologies and their clinical and clinical/research applications are discussed in detail. (Circ J 2014; 78: 1531 -1539

Elevated Levels of Serum Fibrin and Fibrinogen Degradation Products Are Independent Predictors of Larger Coronary Plaques and Greater Plaque Necrotic Core

“…Features suggestive of plaque vulnerability were defined as larger plaques and greater plaque NC, and FF components. 14–17 …”

Spectral analysis assisted photoacoustic imaging for lipid composition differentiation

“…Catheter-based imaging modalities, such as intravascular ultrasound (IVUS) [15], optical coherence tomography (OCT) [16], and near-infrared spectroscopy (NIRS) [17], have been developed to interrogate the artery structure from inside the vessel. IVUS can show the artery morphology with high quality [17].…”

“…IVUS can show the artery morphology with high quality [17]. By combining with virtual histology, it can map the composition distribution within the plaque, thus classify the plaque type [17], [18]. However, the accuracy of virtual histology IVUS has been challenged, especially for the accurate quantification of necrotic core size.…”

A Review of Intravascular Ultrasound-based Multimodal Intravascular Imaging

“…Therefore, to determine the treatment strategy for patients diagnosed with vulnerable plaques by the integrated IVUS-NIRS system, a prospective multi-center observational study of patients undergoing NIRS via TVC imaging system (COLOR Registry) is needed. 61 …”