Measurement of Collagen and Smooth Muscle Cell Content in Atherosclerotic Plaques Using Polarization-Sensitive Optical Coherence Tomography

Abstract

Our results demonstrate that PSOCT enables the measurement of birefringence in plaques and in fibrous caps of necrotic core fibroatheromas. Given its potential to evaluate collagen content, collagen fiber thickness, and SMC density, we anticipate that PSOCT will significantly improve our ability to evaluate plaque stability in patients.

Evaluation of collagen in atherosclerotic plaques: the use of two coherent laser-based imaging methods

“…In NCFAs, PSOCT birefringence highly correlated with collagen content of fibrous caps, potentially providing an important indicator of plaque stability. A strong positive correlation was demonstrated between PSOCT birefringence and thick collagen fiber content (R=0.76, P<0.0001) [37] These results may be influenced by other sources of birefringence due to the compositional heterogeneity in atherosclerotic plaques, such as the presence of cholesterol crystals and SMCs. PSOCT birefringence demonstrated a high correlation with SMC content (R=0.74, P<0.0001) [37].…”

“…A strong positive correlation was demonstrated between PSOCT birefringence and thick collagen fiber content (R=0.76, P<0.0001) [37] These results may be influenced by other sources of birefringence due to the compositional heterogeneity in atherosclerotic plaques, such as the presence of cholesterol crystals and SMCs. PSOCT birefringence demonstrated a high correlation with SMC content (R=0.74, P<0.0001) [37]. Further analysis of PSOCT images may allow a more precise determination of collagen content to be made.…”

“…The system design and the mathematical algorithms to generate PSOCT images have been previously described in detail [34,35] Briefly, by scanning the incident beam across the sample and calculating phase retardation angles using the analyses of Stokes vectors [35], the (double-pass) phase retardation at each point in depth introduced by the sample was obtained and displayed as a gray scale image with black corresponding to 0° (at the tissue surface shown in red) and white corresponding to 180° of phase retardation [36]. This system has been recently investigated for evaluating birefringence in atherosclerotic plaques [37]. The study showed that PSOCT birefringence was highly related to total collagen content, collagen fiber thickness and SMC content in atherosclerotic plaques (Fig.…”

Polarization-Sensitive Optical Coherence Tomography in Cardiology

“…Recently, the identification of organized collagen fiber in arteries has also been demonstrated by using a single-detector PS-OCT (Giattina et al, 2006). In addition, another report showed that the PS-OCT measurements of birefringence have a strong positive correlation with thick collagen fiber content (r = 0.76, p < 0.001) and also a smooth muscle cells density (r = 0.74, p < 0.01) (Nadkarni et al, 2007).…”

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

“…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].…”