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

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 where OCT images could be matched to histology OCT microscope, exactly. Light backscattering coefficient mu(b) and attenuation coefficients mu(t) are determined for three basic plaque. types based on a single-scattering physical model: calcification (mu(b)=4.9 +/- 1.5 mm(-1), mu(t) = 5.7 +/- 1.4 mm(-1)), fibers (mu(b) = 18.4 +/- 6.4 mm(-1), mu(t) = 6.4 +/- 1.2 mm(-1)), and lipid pool (mu(b)=28.1 +/- 8.9 mm(-1), mu(t) = 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. (C) 2008 Society of Photo-Optical Instrumentation Engineers.