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Chapter 19 Blood Flow Measurement
Published in B H Brown, R H Smallwood, D C Barber, P V Lawford, D R Hose, Medical Physics and Biomedical Engineering, 2017
For example, the common carotid artery in the neck divides into the internal and external carotid arteries and disease at this point can give rise to atheromatous plaque that may be dislodged and cause vascular obstructions in the brain or may completely occlude the flow. Doppler imaging systems can be used to image the flow at the bifurcation and detect phenomena such as the turbulence that arises around obstructions to flow. An image of this situation was given in Chapter 12 (section 12.3.6).
Comparison of blood flow analysis in stenosed and stented carotid artery bifurcation models
Published in Cogent Engineering, 2023
M. Saqib Hameed, Awais Ahmad Shah, Muhammad Irfan Khan, Awais Ali, Imtiaz Hussain, Muhammad Dawood Bukhari
The present work focuses on the analysis of flow characteristics in a patient-specific bifurcation of carotid artery. Two computer-aided design (CAD) models were generated and analyzed. The first model contained a stenosis region, while the second model was modelled for an open-cell stent. The blood domain was discretized using the finite volume method (FVM). The proximal end of the common carotid artery (CCA) was designed as velocity inlet; the distal ends of the ICA and the external carotid artery (ECA) were designed as the pressure outlets. The flow was assumed to be constantly divided between ICA and ECA with a ratio of 59:41 (Lee et al., 2008). The models were solved for two steady-state boundary conditions: one near the peak systole and the other at the diastole. The time-independent problem was easier to solve computationally and sufficiently predicts the flow phenomenon around constrictions in the blood vessels (Back et al., 1984). The effect of stenosis and the bend in the ICA on flow variables like velocity planes, vectors, streamlines, pressure contours and WSS contours was studied. The results were then compared with the values of flow variable obtained from the stented model to demonstrate how the introduction of a stent helps in achieving the normal blood flow characteristics.
Computational investigations on the hemodynamic performance of a new swirl generator in bifurcated arteries
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
The present study numerically tests the conceptual design of a new device, the swirl generator that generate helical flow structure in the bifurcated arteries. The swirl generator may be assumed as a stent like structure with an internal grooves. With these criteria, the grooves are provided with triangular ribs at the inner wall of the swirl generator. Figure 2(a) shows the idealized carotid artery model, chosen for the computational study. The common carotid artery (CCA) empties into a smaller external carotid artery (ECA) and a large internal carotid artery (ICA). The length of the helicity generator is three times the CCA diameter and it is placed five diameter proximal (-5D) to the bifurcation zone (Figure 2a) in the CCA passage. The parameters taken for analysis are height of the rib, the helical angle and the number of ribs. Each of these parameters are varied systematically to understand their influence on the hemodynamics and the atherogenises. A total number of 11 different cases are analysed whose details are shown in Figure 3 as well as in Table 1.
The protective mechanism underlying total flavones of Dracocephalum (TFD) effects on rat cerebral ischemia reperfusion injury
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Peng Wu, Xu-sheng Yan, Yu Zhang, Dong-sheng Huo, Wei Song, Xin Fang, He Wang, Zhan-jun Yang, Jian-xin Jia
The MCAO animal model was produced as described by Sim et al. (2016) and Park et al. (2017). Rats were fasted 12 hr prior to the operation, fixed in a stereotaxic frame and anesthetized with 10% chloral hydrate via intraperitoneal (ip) injection. A 2 cm midline left side incision was made on the neck to search and expose the external carotid artery (ECA), internal carotid artery (ICA) and common carotid artery (CCA). The isolated vessels were tied in the sequential order of ECA, CCA followed by ICA with silk sutures. A V shape incision cut was performed in the ICA and a thread coated with poly-lysine (diameter, 0.28 mm) inserted into the ICA to occlude the middle cerebral artery (MCA), which was further advanced until the thread approached the starting point of the MCA. The incision was then tied, the left MCA occluded for 2 hr and subsequently the MCA was re-perfused. The suture was moved approximately 2 mm in the MCA to enable occluded blood to flow. When this process was finished, animals were immediately returned to a single cage.