Geometry Of Carotid Artery Bifurcation Research Articles

Prediction of atherosclerosis diseases using biosensor-assisted deep learning artificial neuron model

In the present medical era, the major cause of the rise in death rate worldwide is atherosclerosis disease and this diagnosis is complicated because initial signs are unattended. To reduce the costs of treatment and prevent serious events, it is necessary to improve the prediction accuracy of cardiovascular diseases during plaque formation. This proposal is intended to create a support system for the biosensor-assisted deep learning concepts for detecting atherosclerosis disease. With the clinical data, this mathematical model can predict heart disease based on deep learning-assisted k-means geometric distribution artificial neuron model. The atherosclerotic plaque formation mathematical model explains the early atherosclerotic lesion development in a more accurate manner. Further, the creation of the atherosclerotic plate, the test performs numerical simulations with idealized two-dimensional carotid artery bifurcation geometry. The proposed system has been analyzed using a variety of similarity tests such as the coefficient Matthews’s correlation (CMC). Furthermore, the results have reached 95.66% accuracy and 0.93 CMC, which are significantly higher than published conventional research.

Meshing strategy for bifurcation arteries in the context of blood flow simulation accuracy

The study presents a mesh dependency study for a carotid artery bifurcation geometry of a real-life specimen. The results of time-averaged velocity profiles at artery control surfaces and wall shear stresses are compared between a set of structured and unstructured meshes, with varying non–dimensional boundary layer first element thickness (y+) parameter. A set of four meshes in total is considered: a full–hexagonal structured mesh, an unstructured tetrahedral mesh with prism inflation layer, both created for y+=1 and y+=30. Apart from numerical results, overall mesh creation work time, overall analysisstability are compared with the mesh quality results: cell non–orthogonality, cell skew and aspect ratio. Numerical results are validated against results of real–life CT examination performed in Poznań Medical University.

Three-dimensional pulsation of rat carotid artery bifurcation observed using a high-resolution ultrasound imaging system

The arterial structure experiences cyclic pulsation in three-dimension (3-D) by pulsatile blood flow. Here we reconstruct the 3-D carotid artery bifurcation (CAB) geometry from three rats to observe the pulsatile variation of the carotid artery geometry by a high-resolution ultrasound imaging system (Vevo 770, VisualSonics, Canada). Two experienced observers manually segmented the cross-sectional ultrasound images to outline the arterial lumen. From the constructed geometry of three subjects, we observed that the CAB geometry favorably expanded to anterior/ posterior direction which parallel to sagittal plane. Furthermore, an in vitro blood flow experiment using an anthropomorphic flow phantom was implemented to more clearly understand the asymmetric pulsation phenomenon. Finally we confirmed the elastic bifurcation geometry favorably expands in a direction of bifurcation, both in vivo and in vitro measurements, which derived by bifurcated flow. This finding, the asymmetrical pulsation phenomenon of carotid bifurcation in 3-D, may be useful in understanding hemodynamic etiology of cardiovascular diseases and also provide more realistic input data for computer simulation of hemodynamics. [This work was supported by MSIP Korea, under the C-ITRC support program (NIPA-2014-H0401-14-1002) supervised by the NIPA and also supported by the Richard Merkin Visiting Fellowship Program of the Focused Ultrasound Foundation.]

Cyclic variation of three-dimensional geometry of the rat carotid artery bifurcation assessed by high-frequency ultrasound imaging

The computational simulation of the interaction between blood flow and arterial wall motion during a cardiac cycle is complicated and requires high quality information of the vessel wall motion in space and time. In this study, a set of cross-sectional ultrasound images was acquired using an electrocardiogram-gated kilohertz visualization mode, which provides 1000 frame images per second, by an ultrasound imaging system (Vevo 770, VisualSonics, Canada) with a probe of 40-MHz central frequency (RMV 704). The three dimensional (3D) geometry of carotid artery bifurcation was reconstructed at systolic and diastolic phases during a cardiac cycle using the cross-sectional ultrasound images, and a block meshing method was applied to the reconstructed 3D geometry. Then, an appropriate hexahedral mesh was constructed for the computational simulation. The 3D geometry measured by high-frequency ultrasound imaging provides high temporal and spatial information on the vessel wall motion during a cardiac cycle, which is important for accurate computational simulation of hemodynamics in the bifurcation area of the carotid artery. The fluid-structure interaction simulation of blood flow in the carotid artery bifurcation during a cardiac cycle is in progress using the meshes of 3D geometry of vessel wall. [Work supported by NIPA-2013-H0401-13-1007 and 2013R1A1A2043478.]

Asymmetric radial expansion and contraction of rat carotid artery observed using a high-resolution ultrasound imaging system

The geometry of carotid artery bifurcation is of high clinical interest because it determines the characteristics of blood flow that is closely related to the formation and development of atherosclerotic plaque. However, information on the dynamic changes in the vessel wall of carotid artery bifurcation during a pulsatile cycle is limited. This pilot study investigated the cyclic changes in carotid artery geometry caused by blood flow pulsation in rats. A high-resolution ultrasound imaging system with a broadband scanhead centered at 40MHz was used to obtain longitudinal images of the rat carotid artery. A high frame rate retrospective B-scan imaging technique based on the use of electrocardiogram to trigger signal acquisition was used to examine precisely the fast arterial wall motion. Two-dimensional geometry data obtained from nine rats showed that the rat carotid artery asymmetrically contracts and dilates during each cardiac cycle. Systolic/diastolic vessel diameters near the upstream and downstream regions from the bifurcation were 0.976±0.011/0.825±0.015mm and 0.766±0.015/0.650±0.016mm, respectively. Their posterior/anterior wall displacement ratios in the radial direction were 41.0±14.9% and 2.9±1.6%, respectively. These results indicate that in the vicinity of bifurcation, the carotid artery favorably expands to the anterior side during the systolic phase. This phenomenon was observed to be more prominent in the downstream region near the bifurcation. The cyclic variation pattern in wall movement varies depending on the measurement site, which shows different patterns at far upstream and downstream of the bifurcation. The asymmetric radial expansion and contraction of the rat carotid artery observed in this study may be useful in studying the hemodynamic etiology of cardiovascular diseases because the pulsatile changes in vessel geometry may affect the local hemodynamics that determines the spatial distribution of wall shear stress, one of important cardiovascular risk factors. Further systematic study is needed to clarify the effects of wall elasticity, branch angle and vessel diameter ratio on the asymmetric wall motion of carotid artery bifurcation.