Analysis of Blood Flow Patterns to Estimate Atherosclerosis Formation in the Left Carotid Artery by Cfd Simulation

Abstract Background: Superb micro-vascular imaging (SMI) provided new advances in vascular imaging, resulting in revealing the overall vascularity detection of small or microflow states without the use of contrast media. This study aimed to explore the blood supply andfeeding artery of carotid body tumor (CBT) on SMI for providing more accurate information for surgery.Results: Twenty-six CBT lesions underwent color Doppler flow imaging (CDFI) and SMI, and were confirmed later by pathology. The blood flow patterns and feeding artery of CBTson CDFI and SMI were graded and compared.Compared with the application of CDFI, the pattern of more CBT lesionschanged to a higher Adler category by SMI (P<0.001). Thefeeding artery of two CBT lesions, which fail to show by CDFI, was internal carotid artery(ICA) by SMI and compared with CDFI the feeding artery of three changed from ICA or external carotid artery(ECA) to MIX (both ICA and ECA) by SMI. We classified the feeding artery of CBTs into originating from ICA or others (including ECA and MIX). For all the lesions, threelesions that stemmed from ICA and 23lesions that stemmed from ECAor MIX. CBT lesions stemming from ECA or MIX with Adler II or Adler III blood flow patterns accounted for 30.4% (7/23) or 69.6% (16/23), respectively, while CBT lesions stemming from ICA with Adler I or Adler II blood flow patterns accounted for 66.7% (2/3) or 33.3% (1/3), respectively. Conclusions: SMI is superior to CDFI in detecting vascularity of CBTs, and SMI could better investigate the origin of feeding vessels of CBTs in comparison to CDFI.Compared with those originating from ECA, CBTs from ICA has less vascularity.

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Abstract WP139: The Correlation Between Supraorbital Artery Flow Patterns and Degree of Carotid Artery Stenosis

Stroke ◽

10.1161/str.48.suppl_1.wp139 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Xiao Tong Xu ◽

Ning Ma ◽

Huadong Wu ◽

Zhongrong Miao ◽

Dapeng Mo

Keyword(s):

Blood Flow ◽

Carotid Artery ◽

Reverse Flow ◽

Anatomical Variations ◽

Flow Patterns ◽

Conventional Angiography ◽

Ica Stenosis ◽

Relationship Of ◽

Blood Flow Patterns ◽

The Relationship

Objective: Patients with internal carotid artery (ICA) occlusion or severe stenosis usually have collateral via ophthalmic artery (OA). However, the relationship of blood flow patterns of OA and the degree of ICA stenosis has been rarely reported. Transcranial Doppler (TCD) is a promising modality to assess OA collateral when ICA lesion. Considered OA characteristics including tortuosity and anatomical variations, we try to evaluate the supraorbital artery (SA), the one of OA terminal branches, to analyze the relationship of flow with the degree of ICA stenosis. Materials and Methods: From Jun 2012 to Jan 2015, TCD were performed to 40 patients with ICA stenosis before and after carotid artery stenting (CAS). SA blood flow patterns were compared with the degree of ICA stenosis confirmed by conventional angiography. Results: 40 patients (29 men) were enrolled (mean age 64.9 yrs). Before CAS, the retrograde blood of SA was found in 40 patients. After stenting, the flow pattern reversed in 29 patients of these patients (29/40, 72.5%). The blood flow of SA was gradually reverse over time from angioplasty with balloon to several days after CAS. The patterns of these changes were categorized into four types: (A), flow spectrum completely reversed; (B), reverse flow spectrum associated with systolic notch; (C), flow spectrum forward at systolic and reverse at diastolic; (D), type flow spectrum entirely forward. Before balloon angioplasty (mean stenosis, 93.4%), A type was found in 39 of them, B type in 1 patient; after balloon dilatation (mean stenosis, 82.9%), 26 A types and 4 B, 5 C, 5 D types. Stent (mean stenosis, 14.9%), 1 A type, 4 B and 4 C, 29 D types. Conclusion: The flood flow patterns of SA may be associated with the degree of carotid stenosis evaluated with TCD and the blood flow may be reverse after CAS. This work was supported by the National Natural Science Foundation of China (Contractgrant number: 81471390 to N.M).

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Analysis of Blood Flow Patterns to Estimate Atherosclerosis Formation in the Left Carotid Artery by CFD Simulation

Volume 3: Computational Fluid Dynamics; Micro and Nano Fluid Dynamics ◽

10.1115/fedsm2020-20052 ◽

2020 ◽

Author(s):

Marzia Momin ◽

Nusrat Ara ◽

M. Tarik Arafat

Keyword(s):

Blood Flow ◽

Shear Stress ◽

Carotid Artery ◽

Wall Shear Stress ◽

Cfd Simulation ◽

Lower Percentage ◽

Hemodynamic Parameters ◽

Left Carotid Artery ◽

Bifurcation Angle ◽

Wall Shear

Abstract The purpose of this computational fluid dynamics (CFD) study is to simulate left carotid artery models to evaluate the influence of hematocrit (Hct) level and angle of bifurcation on the formation of atherosclerosis. Bifurcation angle can vary from person to person based on sex, age or diseased condition which has an impact on hemo-dynamic parameters. From the anatomical study, it is seen that the carotid artery bifurcation is the preferential region for atherosclerosis formation. The combination of bifurcation, curvature and diameter change in this bifurcation region causes the blood flow to be complex with recirculation regions and secondary flows which influence hemodynamic changes and the formation of atherosclerosis. Along with the bifurcation angle, the Hct level also influences on changing hemodynamic parameters. As the viscosity of blood is mainly controlled by the Hct level, the hemodynamic parameters of blood are changed on the basis of change in percentage of the Hct level. Therefore, the Hct percentage can act as a risk factor for atherosclerosis formation. We have assessed the probability of vulnerable atherosclerosis formation based on the change of both bifurcation angle and hematocrit level. In this study, three different carotid artery geometries with 40 degree, 48.5 degree, and 63.6 degree angles were simulated at a varying percentage of the Hct level. We discerned these models by using CFD simulation to calculate wall shear stress (WSS), time-averaged wall shear stress (TAWSS) and velocity. The effects of angulation and Hct percentage on the velocity of blood were studied on the plane of the bifurcation region. The carotid artery with 63.6 degree angulation faces more recirculation areas and peak recirculation areas are observed at 25% Hct level. This justifies the reason behind atherosclerosis formation in the artery. We observed low WSS at wider angled models and a high WSS at narrow angled models. WSS value is also affected by the percentage of Hct. In this study, we noticed a lower value of WSS at a lower percentage of Hct which is responsible for atherosclerosis formation. The WSS value of 0.4 Pa was considered as the critical point for the atherosclerosis formation. We also calculated time-averaged wall shear stress (TAWSS) which is similar to the WSS contour plot. Overall, after analyzing the results of velocity, WSS and TAWSS, we concluded that low Hct (around 25% or lower) along with higher bifurcation angle (around 63.6 degree or higher) are more accountable for atherosclerosis formation.

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