Characterization of atherosclerosis plaques by measuring both backscattering and attenuation coefficients in optical coherence tomography

TLDR

Intravascular optical coherence tomography (OCT) is a powerful diagnostic tool for cardiovascular diseases, yet the optical mechanisms underlying its qualitative observations remain unclear. The study aims to resolve the fundamental issues that impede accurate tissue characterization of OCT images from coronary arteries. To this end, the authors measured both attenuation and backscattering properties of plaque components in postmortem human coronary arteries, examining samples from the lumen surface with a catheter and from transverse cuts with an OCT microscope matched to histology. They determined backscattering and attenuation coefficients for calcification, fibers, and lipid pools, showing that combining these measurements explains many OCT features and enhances contrast for better tissue characterization.

Abstract

Intravascular optical coherence tomography (OCT) has been proven a powerful diagnostic tool for cardiovascular diseases. However, the optical mechanism for the qualitative observations are still absent. We address the fundamental issues that underlie the tissue characterization of OCT images obtained from coronary arteries. For this, we investigate both the attenuation and the backscattering properties of different plaque components of postmortem human cadaver coronary arteries. The artery samples are examined both from lumen surface using a catheter and from transversely cut surface using an OCT microscope, where OCT images could be matched to histology exactly. Light backscattering coefficient µb and attenuation coefficients µt are determined for three basic plaque types based on a single-scattering physical model: calcification (µb=4.9±1.5 mm−1, µt=5.7±1.4 mm−1), fibers (µb=18.4±6.4 mm−1, µt=6.4±1.2 mm−1), and lipid pool (µb=28.1±8.9 mm−1, µt=13.7±4.5 mm−1). Our results not only explain the origins of many qualitative OCT features, but also show that combination of backscattering and attenuation coefficient measurements can be used for contrast enhancing and better tissue characterization.