Characterization of Human Atherosclerosis by Optical Coherence Tomography

Abstract

Background-High-resolution visualization of atherosclerotic plaque morphology may be essential for identifying coronary plaques that cause acute coronary events. Optical coherence tomography (OCT) is an intravascular imaging modality capable of providing cross-sectional images of tissue with a resolution of 10 m. To date, OCT imaging has not been investigated in sufficient detail to assess its accuracy for characterizing atherosclerotic plaques. The aim of this study was to establish objective OCT image criteria for atherosclerotic plaque characterization in vitro. Methods and Results-OCT images of 357 (diseased) atherosclerotic arterial segments obtained at autopsy were correlated with histology. OCT image criteria for 3 types of plaque were formulated by analysis of a subset (nϭ50) of arterial segments. OCT images of fibrous plaques were characterized by homogeneous, signal-rich regions; fibrocalcific plaques by well-delineated, signal-poor regions with sharp borders; and lipid-rich plaques by signal-poor regions with diffuse borders. Independent validation of these criteria by 2 OCT readers for the remaining segments (nϭ307) demonstrated a sensitivity and specificity ranging from 71% to 79% and 97% to 98% for fibrous plaques, 95% to 96% and 97% for fibrocalcific plaques, and 90% to 94% and 90% to 92% for lipid-rich plaques, respectively (overall agreement, ϭ0.83 to 0.84). The interobserver and intraobserver reliabilities of OCT assessment were high ( values of 0.88 and 0.91, respectively). Conclusions-Objective OCT criteria are highly sensitive and specific for characterizing different types of atherosclerotic plaques. These results represent an important step in validating this new intravascular imaging modality and will provide a basis for the interpretation of intracoronary OCT images obtained from patients.

Impact of Lesion Length on Functional Significance in Intermediate Coronary Lesions

“…1 -3 Optical coherence tomography, which can provide a detailed evaluation of the plaque nature, has also been developed. 4,5 Although physiological assessment, including stress electrocardiogram, echocardiography, and single-photon emission computed tomography (SPECT) cannot be performed simultaneously with anatomical assessment, the assessment of physiological indicators by fractional myocardial flow reserve (FFR) using a pressure wire in recent years has allowed simultaneous evaluation with CAG. An FFR value <0.80 identifies ischemia-causing coronary stenoses with an accuracy of >90%.…”

A New 3-D Automated Computational Method to Evaluate In-Stent Neointimal Hyperplasia in In-Vivo Intravascular Optical Coherence Tomography Pullbacks

“…The biggest advantage of OCT is its high resolution, on the order of 15 microns spatially, but at the cost of a decreased penetration depth of 1mm to 2mm. Both in vitro and in vivo studies [2,4] have shown that the resolution of OCT can differentiate between typical constituents of atherosclerotic plaques, such as lipid, calcium, and fibrous tissue better than IVUS [5], and can also resolve the thin fibrous cap that is thought to be responsible for plaque vulnerability [6].…”

Clinical Characteristics of In-stent Neoatherosclerosis Causing Late Stent Failure

“…Briefly, the imaging wire was automatically pulled back from a distal to proximal position and lactate Ringer's solution was continuously infused from the tip of the occlusion balloon in the M3 system and contrast media was continuously infused in the C7 system to displace blood 13,14) .…”