Comparison of 3D reconstruction methods based on different cardiovascular imaging: a study of multimodality reconstruction method (original) (raw)
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The International Journal of Cardiovascular Imaging, 2015
Wall stress (WS) is associated with high arterial pressure and affects the localization of atherosclerotic lesions. We sought to non-invasively investigate the distribution of WS along the length of human coronary arteries and investigate its potential effect on atherosclerosis in association with vascular stiffness, local arterial curvature and plaque volume. We reconstructed three-dimensionally 28 coronary arteries from 22 subjects who had undergone coronary computed tomography angiography. Coronary arteries were divided in 2 mm-long segments. WS, vascular stiffness, plaque volume and curvature were calculated in each segment using computational fluid dynamics and morphology measurements. Plaque segments exhibited lower WS compared to their adjacent normal segments. Within plaques, WS was lower in the mid plaque portion compared to the upstream portion. Plaque volume was higher in the mid plaque portion compared to upstream and downstream portions. Low WS was associated with high curvature and both low WS and high curvature were associated with increased plaque volume. The current study demonstrates that WS and plaque volume are not uniform in the longitudinal axis of human coronary plaque. Calculation of WS could serve as a surrogate for the localization of plaque development and the identification of plaques at a more advanced stage of progression.
Medical Physics, 2012
Purpose: Atheromatic plaque progression is affected, among others phenomena, by biomechanical, biochemical, and physiological factors. In this paper, the authors introduce a novel framework able to provide both morphological (vessel radius, plaque thickness, and type) and biomechanical (wall shear stress and Von Mises stress) indices of coronary arteries. Methods: First, the approach reconstructs the three-dimensional morphology of the vessel from intravascular ultrasound (IVUS) and Angiographic sequences, requiring minimal user interaction. Then, a computational pipeline allows to automatically assess fluid-dynamic and mechanical indices. Ten coronary arteries are analyzed illustrating the capabilities of the tool and confirming previous technical and clinical observations. Results: The relations between the arterial indices obtained by IVUS measurement and simulations have been quantitatively analyzed along the whole surface of the artery, extending the analysis of the coronary arteries shown in previous state of the art studies. Additionally, for the first time in the literature, the framework allows the computation of the membrane stresses using a simplified mechanical model of the arterial wall. Conclusions: Circumferentially (within a given frame), statistical analysis shows an inverse relation between the wall shear stress and the plaque thickness. At the global level (comparing a frame within the entire vessel), it is observed that heavy plaque accumulations are in general calcified and are located in the areas of the vessel having high wall shear stress. Finally, in their experiments the inverse proportionality between fluid and structural stresses is observed.
Influence of shear stress magnitude and direction on atherosclerotic plaque composition
Royal Society Open Science, 2016
The precise flow characteristics that promote different atherosclerotic plaque types remain unclear. We previously developed a blood flow-modifying cuff for ApoE −/− mice that induces the development of advanced plaques with vulnerable and stable features upstream and downstream of the cuff, respectively. Herein, we sought to test the hypothesis that changes in flow magnitude promote formation of the upstream (vulnerable) plaque, whereas altered flow direction is important for development of the downstream (stable) plaque. We instrumented ApoE −/− mice ( n = 7) with a cuff around the left carotid artery and imaged them with micro-CT (39.6 µm resolution) eight to nine weeks after cuff placement. Computational fluid dynamics was then performed to compute six metrics that describe different aspects of atherogenic flow in terms of wall shear stress magnitude and/or direction. In a subset of four imaged animals, we performed histology to confirm the presence of advanced plaques and meas...
Catheterization and Cardiovascular Interventions, 2003
The purpose of this study was to assess the reproducibility of an in vivo methodology to reconstruct the lumen, plaque, and external elastic membrane (EEM) of coronary arteries and estimate endothelial shear stress (ESS). Ten coronary arteries without significant stenoses (five native and five stented arteries) were investigated. The 3D lumen and EEM boundaries of each coronary artery were determined by fusing end-diastolic intravascular ultrasound images with biplane coronary angiograms. Coronary flow was measured. Computational fluid dynamics was used to calculate local ESS. Complete data acquisition was then repeated. Analysis was performed on each data set in a blinded manner. The intertest correlation coefficients for all arteries for the two measurements of lumen radius, EEM radius, plaque thickness, and ESS were r ؍ 0.96, 0.96, 0.94, 0.91, respectively (all P values < 0.0001). The 3D anatomy and ESS of human coronary arteries can be reproducibly estimated in vivo. This methodology provides a tool to examine the effect of ESS on atherogenesis, remodeling, and restenosis; the contribution of arterial remodeling and plaque growth to changes in the lumen; and the impact of new therapies. Catheter Cardiovasc Interv 2003;60:67-78.
PLOS ONE, 2015
The relationship between low endothelial shear stress (ESS) and coronary atherosclerosis is well established. ESS assessment so far depended on invasive procedures. The aim of this study was to demonstrate the relationship between ESS and coronary atherosclerosis by using non-invasive coronary computed tomography angiography (CTA) for computational fluid dynamics (CFD) simulations. Methods A total number of 7 consecutive patients with suspected coronary artery disease who received CTA and invasive angiography with IVUS analysis were included in this study. CTA examinations were performed using a dual-source scanner. These datasets were used to build a 3D mesh model. CFD calculations were performed using a validated CFD solver. The presence of plaque was assumed if the thickness of the intima-media complex exceeded 0.3 mm in IVUS. Plaque composition was derived by IVUS radiofrequency data analysis. Results Plaque was present in 32.1% of all analyzed cross-sections. Plaque prevalence was highest in areas of low ESS (49.6%) and high ESS (34.8%). In parts exposed to intermediatelow and intermediate-high ESS few plaques were found (20.0% and 24.0%) (p<0.001). Wall thickness was closely associated with local ESS. Intima-media thickness was 0.43AE0.34mm in low and 0.38AE0.32mm in high ESS segments. It was significantly lower
Lecture Notes in Computer Science, 2005
The relationships among vascular geometry, hemodynamics, and plaque development in coronary arteries are not yet well understood. This in-vivo study was based on the observation that plaque frequently develops at the inner curvature of a vessel, presumably due to a relatively lower wall shear stress. We have shown that circumferential plaque distribution depends on the vessel curvature in the majority of vessels. Consequently, we studied the correlation of plaque distribution and hemodynamics in a set of 48 vessel segments reconstructed by 3-D fusion of intravascular ultrasound and x-ray angiography. The inverse relationship between local wall shear stress and plaque thickness was significantly more pronounced (p<0.025) in vessel cross sections exhibiting compensatory enlargement (positive remodeling) without luminal narrowing than when the full spectrum of vessel stenosis severity was considered. Our findings confirmed that relatively lower wall shear stress is associated with increased plaque development.
The International Journal of Cardiovascular Imaging, 2010
Wall shear stress, the force per area acting on the lumen wall due to the blood flow, is an important biomechanical parameter in the localization and progression of atherosclerosis. To calculate shear stress and relate it to atherosclerosis, a 3D description of the lumen and vessel wall is required. We present a framework to obtain the 3D reconstruction of human coronary arteries by the fusion of intravascular ultrasound (IVUS) and coronary computed tomography angiography (CT). We imaged 23 patients with IVUS and CT. The images from both modalities were registered for 35 arteries, using bifurcations as landmarks. The IVUS images together with IVUS derived lumen and wall contours were positioned on the 3D centerline, which was derived from CT. The resulting 3D lumen and wall contours were transformed to a surface for calculation of shear stress and plaque thickness. We applied variations in selection of landmarks and investigated whether these variations influenced the relation between shear stress and plaque thickness. Fusion was successfully achieved in 31 of the 35 Electronic supplementary material The online version of this article (arteries. The average length of the fused segments was 36.4 ± 15.7 mm. The length in IVUS and CT of the fused parts correlated excellently (R 2 = 0.98). Both for a mildly diseased and a very diseased coronary artery, shear stress was calculated and related to plaque thickness. Variations in the selection of the landmarks for these two arteries did not affect the relationship between shear stress and plaque thickness. This new framework can therefore successfully be applied for shear stress analysis in human coronary arteries.
Medical Engineering & Physics, 2003
Atherosclerosis is a diffuse arterial disease developing over many years and resulting in a complicated three-dimensional arterial morphology. The arterial wall material properties have been demonstrated to show regional alterations with atheroma development and growth. We present a mechanical analysis of diseased arterial segments reconstructed from intravascular ultrasound images in order to quantitatively identify regional alterations in the elastic constants with atherosclerotic lesions. We employ a finite element and a displacement sensitivity analysis to divide the arterial segment into regions with different material properties and use an optimization algorithm to identify the elastic constants in these regions. The results with regional variations identified with this method correlated qualitatively with the extent and location of atherosclerotic lesions identified by visual inspection of the affected arteries. The optimized elastic modulus in regions affected by early atherosclerotic lesions ranged from 90.9 to 93.0 kPa where as the corresponding magnitudes in normal arterial segments ranged from 97.9 to 101.0 kPa. This method can be potentially employed to identify the extent and location of atherosclerotic lesions in a systematic analysis and may potentially be used for the early detection of lesion growth.