Tissue Characterization Of Coronary Plaques Research Articles

Development of 60MHz integrated backscatter intravascular ultrasound and tissue characterization of attenuated signal coronary plaques that cause myocardial injury after percutaneous coronary intervention.

The purpose of the present study was to develop a 60MHz integrated backscatter intravascular ultrasound (IB-IVUS) and to evaluate its usefulness for the detection of lipid area with backward attenuation of ultrasound signal (AT) that for the prediction of post-procedural myocardial injury (PMI) after percutaneous coronary intervention (PCI). In a pathological study, images were acquired from 221 cross-sections of 18 coronary arteries from 13 cadavers obtained at autopsy. In the clinical training study, we compared non-targeted plaques in 38 patients by a previous IB-IVUS system (38MHz) and a new IB-IVUS system (60MHz). In the clinical testing study, we included 70 consecutive patients who underwent PCI. Serum troponin-I was measured just before and 24h after PCI to evaluate PMI. As the % microcalcification + % cholesterol cleft area increased, the attenuation of IB values increased (r = 0.56, p < 0.001). The slopes of regression lines of the area of each tissue component between 38 and 60MHz IB-IVUS were excellent. The lipid pool area with AT tended to be more useful than that of the conventional lipid pool area for the prediction of PMI (p = 0.11). We developed a 60MHz IB-IVUS imaging system for tissue characterization of coronary plaques. Cutoff value of purple color was the most reliable value for the prediction of PMI.

Observation of plaque behavior and tissue characterization of coronary plaque using speckle tracking intravascular ultrasound (ST-IVUS) and iMap imaging system.

Tissue characterization plays an important role in the development of acute coronary syndromes. iMap is an intravascular ultrasound (IVUS) tissue characterization system that provides useful information by reconstructing color-coded maps. Mechanical properties due to dynamic mechanical stress during a cardiac cycle may also trigger vulnerable plaque. Speckle tracking IVUS (ST-IVUS) has been introduced to observe plaque behavior in relation to mechanical properties. We report the case of an 84-year-old woman with stable coronary artery disease who underwent percutaneous coronary intervention, at which time IVUS demonstrated mainly three low echoic areas like lipid pools with thick fibrous caps. Pathological evaluation with iMap revealed that one low echoic area was occupied with necrotic tissue and that the other two areas occupied fibrotic. Although those tissue characterizations were different, they showed similar stretching behavior at systole by ST-IVUS which depicted plaque behavior from IVUS images using a color mapping. The mechanical properties of individual coronary plaques may differ depending on the tissue disposition. It is necessary to consider mechanical properties using ST-IVUS as well as to evaluate tissue characterization in plaque risk stratification.

Optimal Conditions for 3D Non-contrast T1-weighted Magnetic Resonance Imaging Segmented Turbo Fast Low-angle Shot for Tissue Characterization of Coronary Plaques

In three-dimensional (3D) T1-weighted magnetic resonance imaging used for tissue characterization of coronary plaques, the contrast for electrocardiographic synchronization may vary according to the R-R interval (RR). The coronary artery plaque image shows suppression of the fluid compartment signal for the coronary artery luminal blood as well as the fat signal in the region of interest; in addition, it is necessary to ensure that the value of the plaque-to-muscle signal intensity ratio (PMR) does not change according to the difference in RR. In the current study, the phantom review and clinical data suggested that the PMR changes that occur due to the differences in RR can be minimized by adjusting the inversion time (TI) in the range of the required black blood effect. Moreover, the signal-to-noise ratio (SNR), which varies according to the difference between the RR and the TI, was determined to identify the maximum value flip angle (FA) value that would lead to improvement in the SNR. Thus, signal suppression of the PMR, SNR, and the fluid compartment of the coronary artery luminal blood can be controlled using different RRs with the relational expressions for calculating optimal TI and FA.

B-1-3 周波数ヒストグラム情報を用いた冠動脈プラークの組織性状判別(生体計測(1))

B-1-3 周波数ヒストグラム情報を用いた冠動脈プラークの組織性状判別(生体計測(1))

IVUS Tissue Characterization of Coronary Plaque by Classification Restricted Boltzmann Machine

The tissue characterization of coronary plaque is an important task to assess the atherosclerotic process and the potential risks of their ruptures on patient. Thanks to intravascular ultrasound (IVUS) medical imaging technique, the reflected ultrasound signals from tissues are acquired, then be used to visualize inside the artery by the computer-assisted equipment. Often, the characterization of tissues is based on the analysis of their responding echo intensity. However, the domination of various factors and the data robustness are the realistic challenges of IVUS classification problems. The quality of the visualization totally depends on the proposed classifier of descriptive features along with its algorithm. In this study, our objective is to characterize IVUS tissues by using classification restricted Boltzmann machine (ClassRBM). We propose to binarize feature patterns extracted from time domain signals for the input of ClassRBM. The results show a better evaluation compared to the conventional integrated backscatter IVUS method (IB-IVUS) for the same task.

Intravascular ultrasound-based tissue characterization using modular network self-organizing map

The intravascular ultrasound-based tissue characterization of coronary plaque is important for the early diagnosis of acute coronary syndromes. The conventional tissue characterization techniques however cannot obtain sufficient identification accuracy for various tissue properties, because the feature employed for characterization are static features, which lack dynamical information about backscattered radio-frequency (RF) signals.In this work, we propose a new intravascular ultrasound-based tissue characterization method that uses a modular network self-organizing map (mnSOM) in which each module is composed of an autoregressive model for representing the dynamics of the RF signals.The proposed method can create a map of various dynamical features from the RF signal. This map enables generalized tissue characterizations. The proposed method is verified by comparing its tissue characterization performance with that of the conventional method using real intravascular ultrasound signals.

The relationship between serum levels of total bilirubin and coronary plaque vulnerability.

Previous studies have reported that serum total bilirubin provides some protection against coronary artery disease (CAD); however, the relationship between serum levels of total bilirubin and culprit/target plaque vulnerability in patients with CAD remains unclear. In this study, we investigated the association between total bilirubin and tissue characterization of coronary plaque in patients with CAD. We enrolled 85 consecutive patients with CAD who underwent coronary angiography and intravascular ultrasound analyses [45 with acute coronary syndrome (ACS); 40 with stable angina pectoris (SAP)], and 45 age-matched participants served as the control group. Serum levels of total bilirubin in all participants were measured. The stability of the coronary plaque was compared between the ACS group and the SAP group, and the relationship between serum levels of total bilirubin and the features of coronary plaque was analyzed. Serum levels of total bilirubin in the ACS group were significantly lower than those in the SAP and control groups (P<0.01). Serum levels of total bilirubin were positively associated with fibrous plaques (r=0.386, P<0.001), whereas they were negatively associated with plaque burden (r=-0.413, P<0.001), lipid plaque (r=-0.419, P<0.001), and remodeling index (r=-0.275, P<0.05). Furthermore, an independent association between serum levels of total bilirubin and lipid-rich plaques (odds ratio, 0.78; 95% confidence interval, 0.64-0.95) was observed. Serum total bilirubin levels were found to be inversely associated with coronary plaque vulnerability, and decreased serum levels of total bilirubin may be an important factor for coronary lipid plaque formation, which contributes to the pathogenesis of CAD.

Tissue Characterization of Coronary Plaques as a Key to Relationship between Serum Uric Acid Level and Cardiovascular Disease: A Direct Risk or an Indirect Marker?

Tissue Characterization of Coronary Plaques as a Key to Relationship between Serum Uric Acid Level and Cardiovascular Disease: A Direct Risk or an Indirect Marker?

Multiple k-Nearest Neighbor Classifier and Its Application to Tissue Characterization of Coronary Plaque

Multiple k-Nearest Neighbor Classifier and Its Application to Tissue Characterization of Coronary Plaque

An Integrated Backscatter Ultrasound Technique for Coronary Plaque Imaging

The instability of atherosclerotic coronary plaques is related to their histological composition and the thickness of their fibrous caps. Therefore, recognition of the tissue characteristics of coronary plaques is important to understand and prevent coronary artery disease. Recently, an ultrasound integrated backscatter (IB) technique has been developed. Ultrasound signals have unique characteristics of reflection. That is, the ultrasound IB power ratio is a function of the difference in acoustic characteristic impedance between the medium and target tissue, and the acoustic characteristic impedance is determined by the density of tissue multiplied by the speed of sound. This principle allows for tissue characterization of coronary plaques for the risk stratification in patients with coronary artery disease. Two- and three-dimensional IB color-coded maps for the evaluation of tissue components can be constructed to detect four major components: fibrous, dense fibrosis, lipid pool, and calcification. Many studies have shown the reliability and usefulness of the IB technique.

Application of Subspace Method and Sparse Coding to Tissue Characterization of Coronary Plaque for High-speed Classification

Abstract The major cause of Acute Coronary Syndrome (ACS) is a rupture of coronary plaque. Therefore, the tissue characterization of coronary plaque is important for a diagnosis of ACS. In this study, we propose a method to use sparse features and its neighboring information obtained by a sparse coding. In the proposed method, the Radio Frequency (RF) signal obtained by the IntraVascular UltraSound (IVUS) method is expressed by a linear combination of the basis functions extracted from the learning signals by the sparse coding, and the code patterns of the expansion coeffcients of the basis functions are used for the tissue characterization. In addition, in order to perform a high-speed tissue characterization, the subspace method is employed as the classifier. The effectiveness of the proposed method has been verified by comparing the classification results of the proposed method with those of the frequency analysis-based conventional method applying to the data obtained from the human coronary arteries.

Tissue Characterization of Coronary Plaques as a Key to Reno-Cardiac Syndrome

Tissue Characterization of Coronary Plaques as a Key to Reno-Cardiac Syndrome

Feasibility of tissue characterization of coronary plaques using 320-detector row computed tomography: comparison with integrated backscatter intravascular ultrasound

Recently, a new generation of multi-detector row computed tomography (CT) with 320-detector rows (DR) has become available in the clinical settings. The purpose of the present study was to determine the cutoff values of Hounsfield unit (HU) for discrimination of plaque components by comparing HU of coronary plaques with integrated backscatter intravascular ultrasound (IB-IVUS) serving as a gold standard. Seventy-seven coronary atherosclerotic lesions in 77 patients with angina were visualized by both 320-DR CT (Aquilion One, Toshiba, Japan) and IB-IVUS at the same site. To determine the thresholds for discrimination of plaque components, we compared HU with IB values as a gold standard. Optimal thresholds were determined from receiver operating characteristic (ROC) curves analysis. The HU values of lipid pool (n = 115), fibrosis (n = 93), vessel lumen and calcification (n = 73) were 28 ± 19 HU (range -18 to 69 HU), 98 ± 31 HU (44 to 195 HU), 357 ± 65 HU (227 to 534 HU) and 998 ± 236 HU (366 to 1,489 HU), respectively. The thresholds of 56 HU, 210 HU and 490 HU were the most reliable predictors of lipid pool, fibrosis, vessel lumen and calcification, respectively. Lipid volume measured by 320-DR CT was correlated with that measured by IB-IVUS (r = 0.63, p < 0.05), whereas fibrous volume measured by 320-DR CT was not. Lipid volume measured by 320-DR CT was correlated with that measured by IB-IVUS, whereas fibrous volume was not correlated with that measured by IB-IVUS because manual exclusion of the outside of vessel hindered rigorous discrimination between fibrosis and extravascular components.

A combination of plaque components analyzed by integrated backscatter intravascular ultrasound and serum pregnancy‐associated plasma protein a levels predict the no‐reflow phenomenon during percutaneous coronary intervention

Previous studies reported that integrated backscatter intravascular ultrasound (IB-IVUS) provides high diagnostic accuracy for tissue characterization of coronary plaques and that pregnancy-associated plasma protein A (PAPP-A) could be a marker of adverse cardiac outcome in patients with cardiovascular disease. We examined whether IB-IVUS and PAPP-A levels could predict the incidence of no-reflow during percutaneous coronary intervention (PCI) METHODS AND RESULTS: About 176 consecutive patients (138 men, mean age 68 ± 11 years) who underwent PCI with IB-IVUS were prospectively enrolled. Combined no-reflow, including transient filter no-reflow by using distal protection devices, was observed in 31 patients. The percentages of coronary lipid volume (%LV) analyzed by IB-IVUS and serum PAPP-A were significantly higher in patients with combined no-reflow than normal-reflow. To predict no-reflow, a receiver operating characteristic (ROC) analysis determined cut-off values of %LV as 62% and serum PAPP-A as 7.71 ng/mL. The multivariate logistic regression analysis showed that %LV (hazard ratio 4.5, 95% confidence interval 1.6-13.4, P < 0.01) and PAPP-A (hazard ratio 4.32, 95% confidence interval 1.5-12.7, P < 0.01) were independent predictors of combined no-reflow %LV analyzed by IB-IVUS and serum PAPP-A levels were closely associated with the coronary no-reflow phenomenon. © 2014 Wiley Periodicals, Inc.

Tissue characterization of coronary plaque by kNN classifier with fractal-based features of IVUS RF-signal

We propose a tissue characterization method for coronary plaques by using fractal analysis-based features. Those features are obtained from radiofrequency (RF) signals measured by the intravascular...

Validity and Reliability of New Intravascular Ultrasound Analysis Software for Morphological Measurement of Coronary Artery Disease

Intravascular ultrasound (IVUS) analysis software enables precise planimetry measurement and tissue characterization of coronary plaque. Recently, a new IVUS analysis software compatible with integrated backscatter-IVUS, VISIATLAS(TM), was developed. The validity and reliability of VISIATLAS(TM) were evaluated. Forty patients who underwent IVUS-guided percutaneous coronary intervention were enrolled, and planimetry measurements were performed by 2 observers using VISIATLAS(TM) and echoPlaque(TM). IVUS analysis was performed in non-stent segments in 10 patients (non-target vessel, n=5; target vessel before stent implantation, n=5) at every 2.5mm for 20 slices in each patient. Stent segments were analyzed in the remaining 30 patients. With VISIATLAS(TM), the intraobserver and interobserver intraclass correlation coefficients (ICC) for the area of external elastic membrane (EEM), lumen, and plaque plus media (P+M) were 0.999 and 0.999, 0.996 and 0.993, and 0.993 and 0.991, respectively. The intersoftware ICC for EEM, lumen, and P+M area were 0.997, 0.993, and 0.985, respectively. The ICC of stent volume for intraobserver, interobserver and intersoftware comparisons were 0.997, 0.993, and 0.998, respectively. Bland-Altman plots showed small differences and narrow limits of agreement for all of the above parameters. VISIATLAS(TM) has high repeatability and reproducibility of measurement. This new IVUS analysis software is suitable for accurate measurement of coronary artery and stent structure in future IVUS studies.

Abstract 9489: Clinical Impact of Integrated Backscatter Intravascular Ultrasound (IB-IVUS) Analysis for Predicting Coronary No-Reflow Phenomenon After Percutaneous Coronary Intervention

Background and Aims Coronary no-reflow phenomenon after percutaneous coronary intervention (PCI) is associated with a poor prognosis. It is important to predict and prevent coronary no-reflow after PCI and to use distal protection device appropriately. Previous studies showed that integrated backscatter intravascular ultrasound (IB-IVUS) provided high diagnostic accuracy for tissue characterization of coronary plaques based on histology. The purpose of this study was to investigate the relationship between plaque components assessed by IB-IVUS and coronary no-reflow after PCI. Result The 177 lesions (acute coronary syndrome (ACS), n=69; non-ACS, n=108) in 168 consecutive patients (mean age 69 ± 11 years old) who received PCI using IB-IVUS were enrolled. No-reflow, including transient filter no-reflow by using distal protection device, was observed in 18 ACS lesion (26%) and 12 non-ACS lesion (11%). In both ACS and non-ACS patients, lipid volume at stent deployment lesion, lipid area at minimum lumen site (MLS) and percentage of lipid area (%Lipid) at MLS were significantly larger in no-reflow group compared with the normal-reflow group. A receiver operating characteristic (ROC) analysis was performed to assess lipid volume, lipid area at MLS and %Lipid at MLS to predict coronary no-reflow. In ACS patients, the cut-off values for lipid volume, lipid area at MLS and %Lipid at MLS were determined by ROC analysis as 97mm 3 , 7.2mm 2 and 62%, respectively. Otherwise, in non-ACS patients, the cut-off values for lipid volume, lipid area at MLS and %Lipid at MLS were determined as 93mm 3 , 6.1mm 2 and 64%, respectively. Conclusion Our present study suggests that lipid rich plaque assessed by IB-IVUS should be considered as one of important predictors of coronary no reflow after PCI. These cut-off values determined by present IB-IVUS study could improve our approach to coronary no reflow risk stratification in patients with coronary artery disease.

Effect of Vessel Size on Lipid Content of Coronary Plaques Assessed by Integrated Backscatter Intravascular Ultrasound

Tissue characterization of coronary plaques is feasible using integrated backscatter intravascular ultrasound (IB-IVUS), and higher lipid content has been found in the target lesions of acute coronary syndrome (ACS). The present study was performed to identify clinical and IVUS parameters that correlate with plaque composition assessed by IB-IVUS. A total of 109 patients (age 60.0+/-9.7 years) were evaluated with IVUS and IB-IVUS prior to percutaneous coronary intervention. Patients with ACS had a larger vessel size and higher plaque burden in the target lesion than those with stable angina. Relative lipid content of the target lesion by IB-IVUS was also higher in ACS (43.6%+/-12.0% vs 29.9%+/-14.2%; P<0.001). The remodeling index (r=0.403, P<0.001), plaque burden (%) (r=0.495, P<0.001), and vessel size (r=0.572, P<0.001) significantly correlated with lipid content. In the multiple regression analysis, vessel size was the most important independent predictor of lipid content followed by presence of ACS and the remodeling index. ACS, positive remodeling, and larger plaque burden were associated with higher lipid content of coronary plaque. However, the lipid content on IB-IVUS was also significantly affected by vessel size. Therefore, qualitative, morphologic assessment of coronary plaque rather than simple quantitative analysis of tissue components seems to be more appropriate for the identification of vulnerable plaque using IB-IVUS.

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

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). 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 17dB were the optimal predictors of lipid pool/fibrosis and fibrosis/calcification, respectively, with 38-MHz mode; 42dB and 20dB, 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). 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.

Abstract 5820: Impact of Renal Function on Coronary Plaque Composition at Angiographically Severe Lesions

Background: Recent studies have demonstrated that patients with chronic kidney disease are at high risk of arteriosclerosis. Recently, coronary plaque components can be evaluated by integrated-backscatter intravascular ultrasound (IB-IVUS) and lipid-rich plaque is associated with vulnerable plaque. Objective: The aim of this study was to investigate the relationship between renal function and tissue characterization of coronary plaque at the target stenotic site for percutaneous coronary intervention (PCI). Methods: We prospectively performed IB-IVUS before elective PCI to 89 consecutive patients with stable angina. According to estimated glomerular filtration rate (eGFR), they were divided into the two groups (eGFR &lt; 60 ml/min/1.73m 2 or eGFR ≥ 60 ml/min/1.73m 2 ). The tissue characteristics of the coronary plaque at each target stenotic site were evaluated by three-dimensional IB-IVUS just before PCI procedure. Results: Patients with eGFR &lt; 60 ml/min/1.73m 2 had greater lipid volume and smaller fibrous volume compared to patients with eGFR ≥ 60 ml/min/1.73m 2 on the 3-D IB-IVUS image (36.7±10.6 % vs. 28.7±9.3 %, p &lt; 0.001 and 59.1±8.7 % vs. 66.3±8.3 %, p &lt; 0.001, respectively). eGFR showed a significant negative correlation with lipid volume and had a significant positive correlation with fibrous volume in coronary plaques (r = −0.44, p &lt; 0.001, and r = 0.46, p &lt;0.001, respectively). Conclusion: These data suggest that there is a progressive increase in lipid-rich plaque as renal function deteriorated. Our findings may explain the increasing risk of cardiovascular events in patients with renal dysfunction.