Atherosclerotic tissue characterization in vivo by optical coherence tomography attenuation imaging

Abstract

Optical coherence tomography (OCT) is rapidly becoming the method of choice for assessing arterial wall pathology in vivo. Atherosclerotic plaques can be diagnosed with high accuracy, including measurement of the thickness of fibrous caps, enabling an assessment of the risk of rupture. While the OCT image presents morphological information in highly resolved detail, it relies on interpretation of the images by trained readers for the identification of vessel wall components and tissue type. We present a framework to enable systematic and automatic classification of atherosclerotic plaque constituents, based on the optical attenuation coefficient mu(t) of the tissue. OCT images of 65 coronary artery segments in vitro, obtained from 14 vessels harvested at autopsy, are analyzed and correlated with histology. Vessel wall components can be distinguished based on their optical properties: necrotic core and macrophage infiltration exhibit strong attenuation, mu(t)>or=10 mm(-1), while calcific and fibrous tissue have a lower mu(t) approximately 2-5mm(-1). The algorithm is successfully applied to OCT patient data, demonstrating that the analysis can be used in a clinical setting and assist diagnostics of vessel wall pathology.

Assessment of Coronary Atherosclerosis using Optical Coherence Tomography

“…OCT provides images with less motion artifacts than IVUS, due to its faster frame rate and pullback speed, both of which enable the three-dimensional visualization of the coronary arteries 28) . Three-dimensional visualization is a powerful tool for representing OCT data that helps to develop our understanding of vessel and plaque morphology.…”

Optical coherence tomography—current technology and applications in clinical and biomedical research

“…These models are based on the assumption that the absorption coefficient is very low compared to the scattering coefficient, otherwise their contributions to the signal attenuation cannot be separated, easily. However, the total attenuation coefficient can also contain sufficient information for diagnostic purposes [135][136][137][138].…”

“…OCT can quantify typical characteristics such as the fibrous cap thickness [182], presence of lipid [135], or macrophage infiltration [183]. The degradation of organized collagen fibers can be detected with PS-OCT [84,184], and extraction of local attenuation coefficients enables the automated identification of different tissue structures [137]. With these capabilities of highresolution intravascular imaging and extraction of information about the tissue composition, OCT has become a valuable research tool for studying cardiovascular diseases [185][186][187] and possible treatments [188].…”

Thermo-elastic optical coherence tomography

“…The determination of the tissue type in OCT images usually depends on the interpretation by the image reader. More accurate tissue type contrast may be achieved by new OCT-based imaging modalities, with sensitivity to other physical parameters than scattering alone [12][13][14][15][16].…”