Tissue Characterization of Coronary Plaques and Assessment of Thickness of Fibrous Cap Using Integrated Backscatter Intravascular Ultrasound - Comparison With Histology and Optical Coherence Tomography -

Abstract

Background:The purpose of this study was to develop a new online integrated backscatter intravascular ultrasound (IB-IVUS) system and to validate its ability to measure fibrous cap thickness by comparing IB-IVUS images with those from optical coherence tomography (OCT). Methods and Results:Images were acquired from 125 segments of 26 coronary arteries obtained at autopsy from 11 cadavers. In the training study (n=30), 242 regions-of-interest on color-coded maps were compared with histology. In the validation study, 95 cross-sections were diagnosed by IB-IVUS and histology. In 24 patients with stable angina, 28 arterial cross-sections were imaged by IB-IVUS and OCT in vivo. In the training study, cutoff values of −39 decibels (dB) and −17 dB were the optimal predictors of lipid pool/fibrosis and fibrosis/calcification, respectively, with 38-MHz mode; −42 dB and −20 dB, respectively, with 43-MHz mode. In the validation study, IB classified the fibrous, lipid-rich and fibrocalcific components with an accuracy of 92%, 91% and 95%, respectively. Agreement between the histological and IB-IVUS diagnoses was excellent (Cohen's κ=0.83). There was a correlation between the fibrous cap thickness measured by IB-IVUS and OCT (r=0.74, P<0.001). Conclusions:The IB-IVUS system with improved resolution provides high diagnostic accuracy for the analysis of the tissue characteristics of coronary plaques, and enables estimation of the thickness of the fibrous cap in the clinical setting. (Circ J 2010; 74: 2641 - 2648

Thin Cap Fibroatheroma Defined as Lipid Core Abutting Lumen (LCAL) on Integrated Backscatter Intravascular Ultrasound – Comparison With Optical Coherence Tomography and Correlation With Peri-Procedural Myocardial Infarction –

“…28 In 100 consecutive patients and 100 cross-sections, consisting of fibrous cap thickness measured on both OCT and IB-IVUS, we evaluated whether cap thickness measured on OCT was correlated with that on the newly developed IB-IVUS system. QCA QCA analysis was performed using the computer-based edgedetection Coronary Angiography Analysis System (CAAS II; Pie Medical, Maastricht, The Netherlands) as previously described.…”

Coronary Arterial Remodeling and Out-Stent Plaque Change After Drug-Eluting Stent Implantation

“…The excellent correlation of IB-IVUS and histology has been reported in the validation studies using not only a previous IVUS imaging system (Galaxy, Boston Scientific/Scimed, Natick, MA, USA) but also a new IVUS imaging system (VISIWAVE, Terumo). 27, 29 After tracing vessel, out-stent plaque, and stent area, grayscale IVUS images and IB-IVUS color-coded maps were displayed side-by-side on a monitor. Out-stent plaque tissue components were classified into 4 categories: calcification (red), dense fibrosis (yellow), fibrosis (green), and lipid (blue) according to signal level.…”

“…Moreover, the IB-IVUS system in itself can correct the effect of attenuation. 29 Supportive evidence of chronic coronary arterial response after DES implantation in humans is mostly derived from autopsy studies. IVUS and IB-IVUS are the only systems that enable vessel and out-stent plaque change to be observed in vivo.…”

A Histological and Clinical Comparison of New and Conventional Integrated Backscatter Intravascular Ultrasound (IB-IVUS)

“…12,15,27 In the histological comparison, histology/ IVUS image pairs were classified into 3 categories: calcific, fibrous and lipid-rich according to our previous studies. 12, 27 The inter-observer agreements of IB-IVUS for tissue characterization of plaque type were excellent (Cohen's κ=0.90).…”

“…Histological classification (fibrous, lipid pool and calcification) in the direct comparison was performed as previously reported ( Figure 2B). 12, 15 When there were more than 2 diagnoses in the ROI, the diagnosis that occupied more than half of the area was used. When there were more than 3 diagnoses in the ROI, the ROI was excluded from the comparison.…”