Hemodynamic Changes in the Carotid Artery after Infusion of Normal Saline Using Computational Fluid Dynamics

Purpose: To study the effect of the infusion of normal saline on hemodynamic changes in healthy volunteers using computational fluid dynamics (CFD) simulation. Methods: Eight healthy subjects participated and 16 carotid arteries were used for the CFD analysis. A one-liter intravenous infusion of normal saline was applied to the participants to observe the hemodynamic variations. Blood viscosity was measured before and after the injection of normal saline to apply the blood properties on the CFD modeling. Blood viscosity, shear rate, and wall shear stress were visually and quantitatively shown for the comparison between before and after the infusion of normal saline. Statistical analyses were performed to confirm the difference between the before and after groups. Results: After the infusion of normal saline, decreased blood viscosity was observed in the whole carotid artery. At the internal carotid artery, the recirculation zone with low intensity was found after the injection of normal saline. Increased shear rate and reduced wall shear stress was observed at the carotid bifurcation and internal carotid artery. The hemodynamic differences between before and after groups were statistically significant. Conclusions: The infusion of normal saline affected not only the overall changes of blood flow in the carotid artery but also the decrease of blood viscosity.

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The Carotid Sinus as a Viscometer

Diagnostics ◽

10.3390/diagnostics10110924 ◽

2020 ◽

Vol 10 (11) ◽

pp. 924

Author(s):

Andrew Iskander ◽

Rotem Naftalovich ◽

Niema M. Pahlevan

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Carotid Artery ◽

Normal Saline ◽

Carotid Sinus ◽

Blood Rheology ◽

Hemodynamic Changes ◽

Elegant Method

Our group thought the study by Lee and Kim entitled “Hemodynamic Changes in the Carotid Artery after Infusion of Normal Saline Using Computational Fluid Dynamics” was a very elegant method to discern the changes in blood rheology within the carotid sinus after administration of crystalloid [...]

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Measuring wall shear stress distribution in the carotid artery in an African population: Computational fluid dynamics versus ultrasound doppler velocimetry

Radiography ◽

10.1016/j.radi.2020.11.018 ◽

2020 ◽

Author(s):

S.W.I. Onwuzu ◽

A.C. Ugwu ◽

G.C.E. Mbah ◽

I.S. Elo

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Shear Stress ◽

Carotid Artery ◽

Stress Distribution ◽

Wall Shear Stress ◽

African Population ◽

Doppler Velocimetry ◽

Wall Shear Stress Distribution ◽

Ultrasound Doppler

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Computational Fluid Dynamics of Carotid Arteries After Carotid Endarterectomy or Carotid Artery Stenting Based on Postoperative Patient-Specific Computed Tomography Angiography and Ultrasound Flow Data

Neurosurgery ◽

10.1227/neu.0b013e318208f1a0 ◽

2011 ◽

Vol 68 (4) ◽

pp. 1096-1101 ◽

Cited By ~ 14

Author(s):

Hitoshi Hayase ◽

Koji Tokunaga ◽

Toshio Nakayama ◽

Kenji Sugiu ◽

Ayumi Nishida ◽

...

Keyword(s):

Fluid Dynamics ◽

Computed Tomography ◽

Computational Fluid Dynamics ◽

Carotid Artery ◽

Internal Carotid Artery ◽

Carotid Arteries ◽

Internal Carotid ◽

Patient Specific ◽

Flow Data ◽

Simulation Results

Abstract BACKGROUND: There are significant differences in the postoperative morphological and hemodynamic conditions of the carotid arteries between carotid artery stenting (CAS) and endarterectomy (CEA). OBJECTIVE: To compare the postoperative rheological conditions after CAS with those after CEA with patch angioplasty (patch CEA) through the use of computational fluid dynamics (CFD) based on patient-specific data. METHODS: The rheological conditions in the carotid arteries were simulated in 2 patients after CAS and in 2 patients after patch CEA by CFD calculations. Three-dimensional reconstruction of the carotid arteries was performed with the images obtained with computed tomography angiography. The streamlines and wall shear stress (WSS) were calculated by a supercomputer. Adequate boundary conditions were determined by comparing the simulation results with ultrasound flow data. RESULTS: CFD was successfully calculated for all patients. The differences between the flow velocities of ultrasound data and those of the simulation results were limited. In the streamline analysis, the maximum flow velocities in the internal carotid artery after patch CEA were around two-thirds of those after CAS. Rotational slow flow was observed in the internal carotid artery bulb after patch CEA. WSS analysis found regional low WSS near the outer wall of the bulb. High WSS was observed at the distal end of the arteriotomy after patch CEA and at the residual stenosis after CAS. CONCLUSION: CFD of postoperative carotid arteries disclosed the differences in streamlines and WSS between CAS and patch CEA. CFD may allow us to obtain adequate rheological conditions conducive to achieving the best clinical results.

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Estimation of endothelial shear stress in atherosclerotic lesions detected by intravascular ultrasound using computational fluid dynamics from coronary CT scans with a pulsatile blood flow and an individualized blood viscosity

Clinical Hemorheology and Microcirculation ◽

10.3233/ch-201025 ◽

2021 ◽

pp. 1-14

Author(s):

Adrian Curta ◽

Ahmad Jaber ◽

Johannes Rieber ◽

Holger Hetterich

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Shear Stress ◽

Coronary Arteries ◽

Blood Viscosity ◽

Flow Profile ◽

Cfd Simulations ◽

Coronary Ct ◽

Endothelial Shear Stress

INTRODUCTION: Endothelial shear stress (ESS) is a local hemodynamic factor that is dependent on vessel geometry and influences the process of atherogenesis. As in vivo measurements of ESS are not possible, it must be calculated using computational fluid dynamics (CFD). In this feasibility study we explore CFD-models generated from coronary CT-angiography (CCTA) using an individualised blood viscosity and a pulsatile flow profile derived from in vivo measurements. MATERIALS AND METHODS: We retrospectively recruited 25 consecutive patients who received a CCTA followed by a coronary angiography including intravascular ultrasound (IVUS) and generated 3D models of the coronary arteries from the CT-datasets. We then performed CFD-simulations on these models. Hemodynamically non-relevant stenosis were identified in IVUS. They were isolated in the CFD-model and separated longitudinally into a half with atherosclerotic lesion (AL) and one without (NAL). ESS was measured and compared for both halves. RESULTS: After excluding vessels with no IVUS data or relevant stenosis we isolated 31 hemodynamically non-relevant excentric AL from a total of 14 vessels. AL segments showed consistently significantly lower ESS when compared to their corresponding NAL segments when regarding minimum (0.9 Pa, CI [0.6, 1.2] vs. 1.3 Pa, CI [0.9, 1.8]; p = 0.004), mean (5.0 Pa, CI [3.4, 6.0] vs. 6.7 Pa, CI [5.5, 8.4]; p = 0.008) and maximum ESS values (12.4 Pa, CI [8.6, 14.6] vs. 19.6 Pa, CI [12.4, 21.0]; p = 0.005). Qualitatively ESS was lower on the inside of bifurcations and curvatures. CONCLUSION: CFD simulations of coronary arteries from CCTA with an individualised flow profile and blood viscosity are feasible and could provide further prognostic information and a better risk stratification in coronary artery disease. Further prospective studies are needed to investigate this claim.

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A Computational Fluid Dynamics Study on Nasal Airflow and Shear Stress Before and After Endoscopic Endonasal Surgery for Pituitary Adenoma

10.1145/3473258.3473295 ◽

2021 ◽

Author(s):

Miao Lou ◽

Ya Zhang ◽

Simin Wang ◽

Guoxi Zheng

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Shear Stress ◽

Pituitary Adenoma ◽

Nasal Airflow ◽

Endoscopic Endonasal Surgery ◽

Endonasal Surgery ◽

Endoscopic Endonasal ◽

Before And After

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How patient-specific do internal carotid artery inflow rates need to be for computational fluid dynamics of cerebral aneurysms?

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2020-015993 ◽

2020 ◽

pp. neurintsurg-2020-015993 ◽

Cited By ~ 1

Author(s):

Mehdi Najafi ◽

Nicole M Cancelliere ◽

Olivier Brina ◽

Pierre Bouillot ◽

Maria I Vargas ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Carotid Artery ◽

Internal Carotid Artery ◽

Internal Carotid ◽

Spectral Power ◽

Cerebral Aneurysms ◽

Patient Specific ◽

Perfect Agreement ◽

The Impact

BackgroundComputational fluid dynamics (CFD) has become a popular tool for studying ‘patient-specific’ blood flow dynamics in cerebral aneurysms; however, rarely are the inflow boundary conditions patient-specific. We aimed to test the impact of widespread reliance on generalized inflow rates.MethodsInternal carotid artery (ICA) flow rates were measured via 2D cine phase-contrast MRI for 24 patients scheduled for endovascular therapy of an ICA aneurysm. CFD models were constructed from 3D rotational angiography, and pulsatile inflow rates imposed as measured by MRI or estimated using an average older-adult ICA flow waveform shape scaled by a cycle-average flow rate (Qavg) derived from the patient’s ICA cross-sectional area via an assumed inlet velocity.ResultsThere was good overall qualitative agreement in the magnitudes and spatial distributions of time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and spectral power index (SPI) using generalized versus patient-specific inflows. Sac-averaged quantities showed moderate to good correlations: R2=0.54 (TAWSS), 0.80 (OSI), and 0.68 (SPI). Using patient-specific Qavg to scale the generalized waveform shape resulted in near-perfect agreement for TAWSS, and reduced bias, but not scatter, for SPI. Patient-specific waveform had an impact only on OSI correlations, which improved to R2=0.93.ConclusionsAneurysm CFD demonstrates the ability to stratify cases by nominal hemodynamic ‘risk’ factors when employing an age- and vascular-territory-specific recipe for generalized inflow rates. Qavg has a greater influence than waveform shape, suggesting some improvement could be achieved by including measurement of patient-specific Qavg into aneurysm imaging protocols.

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Clinical Significance of Conversion From Computational Fluid Dynamics to Morphology for Risk Evaluation of Aneurysm Recurrence After Coiling

Neurosurgery ◽

10.1093/neuros/nyz310_503 ◽

2019 ◽

Vol 66 (Supplement_1) ◽

Author(s):

Kouichi Misaki ◽

Iku Nambu ◽

Takehiro Uno ◽

Akifumi Yoshikawa ◽

Naoyuki Uchiyama ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Carotid Artery ◽

Internal Carotid Artery ◽

Pressure Difference ◽

Risk Evaluation ◽

Internal Carotid ◽

Critical Role ◽

Parent Artery ◽

Characteristic Analysis

Abstract INTRODUCTION Hemodynamic factors play a critical role in the recurrence of intracranial aneurysms after coiling. However, the computational fluid dynamics (CFD) analyses are not consistently performed all over the world, and its benefits were limited in the specific institutes. We tried to convert the hemodynamic parameters to morphological factors for the risk evaluation of aneurysm recurrence after coiling. METHODS Using pretreatment 3-dimensional rotational angiography data of 50 internal carotid artery aneurysms (7 recanalized, 43 stable) treated with endovascular coiling, we created a virtual post-coiling model produced by cutting the aneurysm dome for construction of virtual coil plane. At the virtual coil plane, we evaluated the pressure difference, which was defined as the pressure elevation at the coil plane from the parent artery divided by the dynamic pressure at the parent artery. After a statistical analysis of the relationship between the pressure difference and aneurysm recurrence, we performed statistical comparisons of pressure difference with morphological factors. RESULTS Recanalized aneurysms showed a significantly higher pressure difference than stable aneurysms (P < .001). The receiver operating characteristic analysis showed that the area under the curve value for the pressure difference (0.967). Morphologically, all 5 aneurysms that had the virtual coil plane at the line of upper border of internal carotid artery had a significantly higher pressure difference (P < .001) and recurred after coiling (P < .001). CONCLUSION The pressure difference in the virtual post-coiling model had a strong association with aneurysm recurrence after coiling. Additionally, the location of the coil plane as a morphological factor was significantly associated with pressure difference and aneurysm recurrence. The conversion of hemodynamic factors into simple morphological factors may contribute to expanded applications of the CFD analysis.

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Influence of Carotid Artery Stenosis Location on Lesion Progression Using Computational Fluid Dynamics

Volume 5: Biomedical and Biotechnology ◽

10.1115/imece2020-23451 ◽

2020 ◽

Author(s):

Muhamed Albadawi ◽

Yasser Abuouf ◽

Shinichi Ookawara ◽

Mahmoud Ahmed

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Blood Flow ◽

Shear Stress ◽

Carotid Artery ◽

Three Dimensional ◽

Flow Dynamic ◽

Maximum Value ◽

Dynamic Factors ◽

Blood Flow Dynamic

Abstract Atherosclerosis is a major arterial disease characterized by the thickening of the arteries’ walls. The development of stenosis at the carotid bifurcation affects the local variations in blood flow dynamic factors. The carotid artery dynamic factors: including the wall shear stress (WSS), time-averaged wall shear stress (TAWSS) and pressure gradient affect the rate of progression of the stenosis. It is essential to analyze the flow in three-dimensional reconstructed patient-specific geometries with realistic boundary conditions to estimate the blood flow dynamic factors. Hence, a three-dimensional comprehensive model is developed including the non-Newtonian blood flow under pulsatile flow conditions. The model is numerically simulated using computational fluid dynamics solvers along with the medical imaging to investigate the effect of stenosis locations on its progression. The numerically predicted blood flow dynamic factors are analyzed. It was found that the blood flow dynamic factors have the importance to influence the diagnosis and prediction of asymptomatic carotid artery stenosis progression. Based on results, the value of TAWSS at the stenosis in the stenotic Common Carotid Artery (CCA) is 46.68 Pa comparing to 19.24 Pa and 10.049 Pa in Internal Carotid Artery (ICA) and External Carotid Artery (ECA) respectively. Also, it was found that the maximum value of WSS in the healthy artery at the bifurcation with 3.829 Pa. However, in stenotic arteries the maximum value for WSS located at the stenosis throat which was found to be 102.158 Pa for CCA comparing to 46.859 Pa in ICA and 33.658 Pa in ECA.

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