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a Mean carotid artery wall with vessel wall plus plaque thickness is colour coded and mapped on its surface (obtained at baseline). b The 3D thickness map in a shown together with the lumen of the carotid artery. c Vessel wall plus plaque thickness after 3 months of 80 mg of atorvastatin daily treatment. d The 3D thickness map in c shown together with the lumen of the carotid artery
Source publication
Background Quantitative measurements of carotid plaque burden are used to monitor patients and evaluate established interventions as
well as new treatment options.
Purpose Three-dimensional ultrasound (3D US) techniques were developed to noninvasively monitor the progression of carotid artery
disease in both symptomatic and asymptomatic patients....
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Objectives:
The ability of magnetic resonance imaging (MRI) in carotid plaque component identification has been well established. However, compared to the costly nature of MRI, 3-dimensional (3D) ultrasound imaging is a more cost-effective assessment tool. Thus, an attractive alternative for carotid disease monitoring would be to establish a strat...
The carotid bifurcation is a common site of atherosclerotic plaque. Plaque development is thought to occur preferentially at geometrically predisposed areas such as arterial branch points. The aim of this study was to investigate the geometric and anatomical variables that contribute to the development of carotid plaque using three-dimensional (3D)...
Background
There is a need for non-invasive and accurate techniques for assessment of severity of atherosclerotic disease in the carotid arteries. Recently an automated single sweep three-dimensional ultrasound (3D US) technique became available. The aims of this study were to evaluate the feasibility and reproducibility of the automated single swe...
Citations
... Recent advances in three-dimensional (3D) imaging of the vasculature have provided accurate anatomical images. Ultrasonography (US) has been considered as an appropriate modality for successive evaluation of arteries, since it is non-invasive and relatively cheap, and provides geometrical and anatomical information about the artery wall, as well as hemodynamic information about blood flow [12]. Moreover, US can provide morphological information about the plaque components, which may have a crucial influence on the diagnosis and clinical decisions [13]. ...
Purpose:
This study investigated the accuracy of models reconstructed from ultrasound image processing by comparing the radial displacement waveforms of a subject-specific artery model and evaluated stress changes in the proximal shoulder, throat, and distal shoulder of the plaques depending on the degree of carotid artery stenosis.
Methods:
Three groups of subjects (healthy and with less or more than 50% carotid stenosis) were evaluated with ultrasonography. Two-dimensional transverse imaging of the common carotid artery was performed to reconstruct the geometry. A longitudinal view of the same region was recorded to extract the Kelvin viscoelastic model parameters. The pulse pressure waveform and the effective pressure of perivascular tissue were loaded onto the internal and external walls of the model. Effective, circumferential, and principal stresses applied to the plaque throat, proximal shoulder, and distal shoulder in the transverse planes were extracted.
Results:
The radial displacement waveforms of the model were closely correlated with those of image processing in all three groups. The mean of the effective, circumferential, and principal stresses of the healthy arteries were 15.01±4.93, 12.97±5.07, and 12.39±2.86 kPa, respectively. As stenosis increased from mild to significant, the mean values of the effective, circumferential, and first principal stresses increased significantly (97%, 74%, and 103% at the plaque throat, respectively) (P<0.05). The minimum effective stress was at the lipid pool. The effective stress in calcified areas was higher than in other parts of the artery wall.
Conclusion:
This model can discriminate differences in stresses applied to mildly and severely stenotic plaques.
... Although total plaque area (TPA) measurement has emerged as a more accurate metric for stroke risk prediction [19], both IMT and TPA are measured from 2D ultrasound images, acquisition of which requires an operator to locate an imaging plane to be scanned, making an image difficult to reproduce even for the same operator. Therefore, 2D ultrasound measurements are sub-optimal in serial monitoring of plaque [20]. ...
With continuous development of therapeutic options for atherosclerosis, image-based biomarkers sensitive to the effect of new interventions are required to be developed for cost-effective clinical evaluation. Although 3D ultrasound measurement of total plaque volume (TPV) showed the efficacy of high-dose statin, more sensitive biomarkers are needed to establish the efficacy of dietary supplements expected to confer a smaller beneficial effect. This study involved 171 subjects who participated in a one-year placebo-controlled trial evaluating the effect of pomegranate. A framework involving a feature selection technique known as discriminative feature selection (DFS) and a semi-supervised graph-based regression (SSGBR) technique was proposed for sensitive detection of plaque textural changes over the trial. 376 textual features of plaques were extracted from 3D ultrasound images acquired at baseline and a follow-up session. A scalar biomarker for each subject were generated by SSGBR based on prominent textural features selected by DFS. The ability of this biomarker for discriminating pomegranate from placebo subjects was quantified by the p-values obtained in Mann–Whitney U test. The discriminative power of SSGBR was compared with global and local dimensionality reduction techniques, including linear discriminant analysis (LDA), maximum margin criterion (MMC) and Laplacian Eigenmap (LE). Only SSGBR (p=4.12×10−6) and normalized LE (p=0.002) detected a difference between the two groups at the 5% significance level. As compared with ΔTPV, SSGBR reduced the sample size required to establish a significant difference by a factor of 60. The application of this framework will substantially reduce the cost incurred in clinical trials.
... Although total plaque area (TPA) measurement has emerged as a more accurate metric for stroke risk prediction [8] , both IMT and TPA are measured from 2D ultrasound images, acquisition of which requires an operator to choose an imaging plane to be scanned, making an image difficult to reproduce, even for the same operator. Therefore, 2D ultrasound measurements are sub-optimal in serial monitoring of plaque [9] . ...
Background and objective:
Dietary supplements are expected to confer a smaller beneficial effect than medical treatments. Therefore, there is a need to develop cost-effective biomarkers that can demonstrate the efficacy of such supplements for carotid atherosclerosis. The aim of this study is to develop such a biomarker based on the changes of 376 plaque textural features measured from 3D ultrasound images.
Methods:
Since the number of features (376) was greater than the number of subjects (171) in this study, principal component analysis (PCA) was applied to reduce the dimensionality of feature vectors. To generate a scalar biomarker for each subject, elements in the reduced feature vectors produced by PCA were weighted using locality preserving projections (LPP) to capture essential patterns exhibited locally in the feature space. 96 subjects treated by pomegranate juice and tablets, and 75 subjects receiving placebo-matching juice and tablets were evaluated in this study. The discriminative power of the proposed biomarker was evaluated and compared with existing biomarkers using t-tests. As the cost of a clinical trial is directly related to the number of subjects enrolled, the cost-effectiveness of the proposed biomarker was evaluated by sample size estimation.
Results:
The proposed biomarker was more able to discriminate plaque changes exhibited by the pomegranate and placebo groups than total plaque volume (TPV) according to the result of t-tests (TPV: p=0.34, Proposed biomarker: p=1.5×10-5). The sample size required by the new biomarker to detect a significant effect was 20 times smaller than that required by TPV.
Conclusion:
With the increase in cost-effectiveness afforded by the proposed biomarker, more proof-of-principle studies for novel treatment options could be performed.
... However, 2D ultrasound images were difficult to reproduce due to the requirement to localize a 2D image plane in each scanning; for this reason, 2D ultrasound was not optimal in monitoring plaque changes in a longitudinal study. 3D carotid ultrasound has been developed to address this issue [15,16]. Wannarong et al. [8] reported that progression in total plaque volume (TPV) measured from 3D ultrasound ( Fig. 1c) was more able to predict stroke than TPA. ...
... A similar approach has already been successfully tested on animals, e.g. the 3D ultrasonic reconstruction from freehand 2D interrogations, using the standard ultrasonic probe described by Allott et al. [11] The studies showed that ultrasound is able to detect and quantify a low echo structure corresponding to fatty streaks in the Watanabe rabbit aortic arch. In Chiu et al., [12] intimamedia thickness was measured by means of 2D ultrasound images extended to a 3D model. The distance between the carotid wall and lumen surfaces was established on a point-by-point basis. ...
This paper describes the advances in the development and subsequent testing of an imaging device for three-dimensional ultrasound measurement of atherosclerotic plaque in the carotid artery. The embolization from the atherosclerotic carotid plaque is one of the most common causes of ischemic stroke and, therefore, we consider the measurement of the plaque as extremely important. The paper describes the proposed hardware for enhancing the standard ultrasonic probe to provide a possibility of accurate probe positioning and synchronization with the cardiac activity, allowing the precise plaque measurements that were impossible with the standard equipment. The synchronization signal is derived from the output signal of the patient monitor (electrocardiogram (ECG)), processed by a microcontroller-based system, generating the control commands for the linear motion moving the probe. The controlling algorithm synchronizes the movement with the ECG waveform to obtain clear images not disturbed by the heart activity.
... The additional information may also enable evaluation of changes in the volume but also in the surface morphology, providing additional information for stroke risk analysis [23]. The use of 3-d techniques has primarily focused on measuring volume changes through time to monitor disease progression [40]- [42]. landry et al. [40] demonstrated that plaque volume change can be reliably measured using 3-d ultrasound. ...
... The authors proposed the use of 3-d VWT and VWT-change maps for identifying disease progression in relations to disturbances of flow. The authors extended their work in [42], in which they measured VWT volume changes for assessing and monitoring carotid artery disease. ...
The robust border identification of atherosclerotic carotid plaque, the corresponding degree of stenosis of the common carotid artery (CCA), and also the characteristics of the arterial wall, including plaque size, composition, and elasticity, have significant clinical relevance for the assessment of future cardiovascular events. To facilitate the follow-up and analysis of the carotid stenosis in serial clinical investigations, we propose and evaluate an integrated system for the segmentation of atherosclerotic carotid plaque in ultrasound videos of the CCA based on video frame normalization, speckle reduction filtering, M-mode state-based identification, parametric active contours, and snake segmentation. Initially, the cardiac cycle in each video is identified and the video M���mode is generated, thus identifying systolic and diastolic states. The video is then segmented for a time period of at least one full cardiac cycle. The algorithm is initialized in the first video frame of the cardiac cycle, with human assistance if needed, and the moving atherosclerotic plaque borders are tracked and segmented in the subsequent frames. Two different initialization methods are investigated in which initial contours are estimated every 20 video frames. In the first initialization method, the initial snake contour is estimated using morphology operators; in the second initialization method, the Chan���Vese active contour model is used. The performance of the algorithm is evaluated on 43 real CCA digitized videos from B-mode longitudinal ultrasound segments and is compared with the manual segmentations of an expert, available every 20 frames in a time span of 3 to 5 s, covering, in general, 2 cardiac cycles. The segmentation results were very satisfactory, according to the expert objective evaluation, for the two different methods investigated, with true-negative fractions (TNF-specificity) of 83.7 �� 7.6% and 84.3 �� 7.5%; true-positive fractions (TPF-sensitivity) of 85.42 �� 8.1% and 86.1 �� 8.0%; and between the ground truth and the proposed segmentation method, kappa indices (KI) of 84.6% and 85.3% and overlap indices of 74.7% and 75.4%. The segmentation contours were also used to compute the cardiac state identification and radial, longitudinal, and shear strain indices for the CCA wall and plaque between the asymptomatic and symptomatic groups were investigated. The results of this study show that the integrated system investigated in this study can be successfully used for the automated video segmentation of the CCA plaque in ultrasound videos.
... The use of 3-D techniques has primarily focused on measuring volume changes through time to monitor disease progression [90]- [92]. Landry et al. [90] demonstrated that plaque volume change can be reliably measured using 3-D ultrasound. ...
... The authors proposed the use of 3-D VWT and VWT-change maps for identifying disease progression in relations to disturbances of flow. The authors extended their work in [92], where they measured VWT volume changes for assessing and monitoring carotid artery disease. ...
... The use of 3-D techniques has primarily focused on measuring volume changes through time to monitor disease progression [90]- [92]. Landry et al. [90] demonstrated that plaque volume change can be reliably measured using 3-D ultrasound. ...
... The authors proposed the use of 3-D VWT and VWT-change maps for identifying disease progression in relations to disturbances of flow. The authors extended their work in [92], where they measured VWT volume changes for assessing and monitoring carotid artery disease. ...
... If the thickness change was statistically significant, there was a high probability that the change was the result of a biological progression/regression of plaque. Although validation of segmentation accuracy is beyond the scope of this paper, it is important to point out that accuracy validation, especially using in vivo images, involves many issues (Chalana and Kim 1997;Fenster and Chiu 2005;Chiu et al. 2008a). Our previously published algorithm (Chiu et al. 2006(Chiu et al. , 2008b was based on manual segmentation. ...
Quantitative measurements of the progression (or regression) of carotid plaque burden are important in monitoring patients and evaluating new treatment options. We previously developed a quantitative metric to analyze changes in carotid plaque morphology from 3-D ultrasound (US) on a point-by-point basis. This method requires multiple segmentations of the arterial wall and lumen boundaries to obtain the local standard deviation (SD) of vessel-wall-plus-plaque thickness (VWT) so that t-tests could be used to determine whether a change in VWT is statistically significant. However, the requirement for multiple segmentations makes clinical trials laborious and time-consuming. Therefore, this study was designed to establish the relationship between local segmentation SD and local signal difference on the arterial wall and lumen boundaries. We propose metrics to quantify segmentation SD and signal difference on a point-by-point basis, and studied whether the signal difference at arterial wall or lumen boundaries could be used to predict local segmentation SD. The ability to predict the local segmentation SD could eliminate the need of repeated segmentations of a 2-D transverse image to obtain the local segmentation standard deviation, thereby making clinical trials less laborious and saving time. Six subjects involved in this study were associated with different degrees of atherosclerosis: three carotid stenosis subjects with mean plaque area >3 cm2 and >60% carotid stenosis were involved in a clinical study evaluating the effect of atorvastatin, a cholesterol-lowering and plaque-stabilizing drug; and three subjects with carotid plaque area >0.5 cm2 were subjects with moderate atherosclerosis. Our results suggest that when local signal difference is higher than 8 greyscale value (GSV), the local segmentation SD stabilizes at 0.05 mm and is thus predictable. This information provides a target value of local signal difference on the arterial boundaries that should be achieved to obtain an accurate prediction of local segmentation SD. (E-mail: [email protected]
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Objective: Vessel-wall-volume (VWV) and localized vessel-wall-thickness (VWT) measured from 3D ultrasound (US) carotid images are sensitive to anti-atherosclerotic effects of medical/dietary treatments. VWV and VWT measurements require the lumen-intima (LIB) and media-adventitia boundaries (MAB) at the common and internal carotid arteries (CCA and ICA). However, most existing segmentation techniques were capable of automating only CCA segmentation. An approach capable of segmenting the MAB and LIB from the CCA and ICA was required to accelerate VWV and VWT quantification. Methods: Segmentation for CCA and ICA were performed independently using the proposed two-channel U-Net, which was driven by a novel loss function known as the adaptive triple Dice loss (ADTL). A test-time augmentation (TTA) approach is used, in which segmentation was performed three times based on axial images and its flipped versions; the final segmentation was generated by pixel-wise majority voting. Results: Experiments involving 224 3DUS volumes produce a Dice-similarity-coefficient (DSC) of 95.1%$\pm$4.1% and 91.6%$\pm$6.6% for the MAB and LIB, in the CCA, respectively, and 94.2%$\pm$3.3% and 89.0%$\pm$8.1% for the MAB and LIB, in the ICA, respectively. TTA and ATDL independently contributed to a statistically significant improvement to all boundaries except the LIB in ICA. The total time required to segment the entire 3DUS volume (CCA+ICA) is 1.4s. Conclusion: The proposed two-channel U-Net with ADTL and TTA can segment the CCA and ICA accurately and efficiently from the 3DUS volume. Significance: Our approach has the potential to accelerate the transition of 3DUS measurements of carotid atherosclerosis to clinical research.
