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Fernández-Martínez D, González-Fernández MR, Nogales-Asensio JM, Ferrera C. Impact of minimal lumen segmentation uncertainty on patient-specific coronary simulations: A look at FFR CT. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2024; 40:e3822. [PMID: 38566253 DOI: 10.1002/cnm.3822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/20/2024] [Accepted: 03/24/2024] [Indexed: 04/04/2024]
Abstract
We examined the effect of minimal lumen segmentation uncertainty on Fractional Flow Reserve obtained from Coronary Computed Tomography AngiographyFFR CT . A total of 14 patient-specific coronary models with different stenosis locations and degrees of severity were enrolled in this study. The optimal segmented coronary lumens were disturbed using intra± 6 % and inter-operator± 15 % variations on the segmentation threshold.FFR CT was evaluated in each case by 3D-OD CFD simulations. The findings suggest that the sensitivity ofFFR CT to this type of uncertainty increases distally and with the stenosis severity. Cases with moderate or severe distal coronary lesions should undergo either exact and thorough segmentation operations or invasive FFR measurements, particularly if theFFR CT is close to the cutoff (0.80). Therefore, we conclude that it is crucial to consider the lesion's location and degree of severity when evaluatingFFR CT results.
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Affiliation(s)
- Daniel Fernández-Martínez
- Departamento de Ingeniería Mecánica, Energética y de los Materiales, Universidad de Extremadura, Badajoz, Spain
| | | | | | - Conrado Ferrera
- Departamento de Ingeniería Mecánica, Energética y de los Materiales, Universidad de Extremadura, Badajoz, Spain
- Instituto de Computación Científica Avanzada, Universidad de Extremadura, Badajoz, Spain
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2
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Su SS, Li LY, Wang Y, Li YZ. Stroke risk prediction by color Doppler ultrasound of carotid artery-based deep learning using Inception V3 and VGG-16. Front Neurol 2023; 14:1111906. [PMID: 36864909 PMCID: PMC9971808 DOI: 10.3389/fneur.2023.1111906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/16/2023] [Indexed: 02/16/2023] Open
Abstract
Purpose This study aims to automatically classify color Doppler images into two categories for stroke risk prediction based on the carotid plaque. The first category is high-risk carotid vulnerable plaque, and the second is stable carotid plaque. Method In this research study, we used a deep learning framework based on transfer learning to classify color Doppler images into two categories: one is high-risk carotid vulnerable plaque, and the other is stable carotid plaque. The data were collected from the Second Affiliated Hospital of Fujian Medical University, including stable and vulnerable cases. A total of 87 patients with risk factors for atherosclerosis in our hospital were selected. We used 230 color Doppler ultrasound images for each category and further divided those into the training set and test set in a ratio of 70 and 30%, respectively. We have implemented Inception V3 and VGG-16 pre-trained models for this classification task. Results Using the proposed framework, we implemented two transfer deep learning models: Inception V3 and VGG-16. We achieved the highest accuracy of 93.81% by using fine-tuned and adjusted hyperparameters according to our classification problem. Conclusion In this research, we classified color Doppler ultrasound images into high-risk carotid vulnerable and stable carotid plaques. We fine-tuned pre-trained deep learning models to classify color Doppler ultrasound images according to our dataset. Our suggested framework helps prevent incorrect diagnoses caused by low image quality and individual experience, among other factors.
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Affiliation(s)
- Shan-Shan Su
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China,*Correspondence: Shan-Shan Su ✉
| | - Li-Ya Li
- Department of Ultrasound, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China,Li-Ya Li ✉
| | - Yi Wang
- Department of Computed Tomography and Magnetic Resonance Imaging (CT/MRI), The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - Yuan-Zhe Li
- Department of Computed Tomography and Magnetic Resonance Imaging (CT/MRI), The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
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Crespo-Quintanilla JA, Alfaro-Ayala JA, Ramírez-Minguela JJ, Vidal-Lesso A, Cano-Andrade S. A detailed analysis in thoracic aorta by means of the entropy generation rate: Prediction of the atherosclerotic lesion. Proc Inst Mech Eng H 2022; 236:1675-1684. [DOI: 10.1177/09544119221126270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A detailed numerical analysis is carried out in a real human thoracic aorta by means of the Computational Fluid Dynamics (CFD) for the prediction of the atherosclerosis lesion. Common hemodynamics parameters, such as, the oscillatory shear index (OSI) and the time average wall shear stress (TAWSS) are used for the prediction of the atherosclerosis lesion. Furthermore, the entropy generation rate is considered to obtain the main irreversibilities that occurs inside the thoracic aorta for the prediction of the atherosclerosis lesion. The model considers the blood flow inside the thoracic aorta in an unsteady state. The results show contours of velocity, streams lines, velocity profiles and the comparison of the hemodynamics parameters OSI versus TAWSS. Moreover, contours of the entropy generation rate are showed inside the aorta. The time averaged entropy generation rate (TAEGR) is obtained as a result of the entropy generation analysis. Finally, TAEGR index is compared and discussed with the common hemodynamics parameters, OSI and TAWSS. The accuracy to detect prone locations to atherosclerotic development in the real aorta using the TAEGR in comparison to the OSI and the TAWSS is in good agreement.
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Affiliation(s)
| | - Jorge A Alfaro-Ayala
- Department of Chemical Engineering, University of Guanajuato, DCNE, Guanajuato, Mexico
| | | | - Agustín Vidal-Lesso
- Department of Mechanical Engineering, University of Guanajuato, DICIS, Salamanca, Mexico
| | - Sergio Cano-Andrade
- Department of Mechanical Engineering, University of Guanajuato, DICIS, Salamanca, Mexico
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4
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Zhang Z, Fang Q, Zhang Y, Zhu Y, Zhang W, Zhu Y, Deng X. Magnetic resonance analysis of deep cerebral venous vasospasm after subarachnoid hemorrhage in rabbits. Front Cardiovasc Med 2022; 9:1013610. [PMID: 36211577 PMCID: PMC9532692 DOI: 10.3389/fcvm.2022.1013610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 08/29/2022] [Indexed: 11/30/2022] Open
Abstract
Objective Arterial spasm is proved to be an inducer of cerebral ischemia and cerebral infarction, while when a venous spasm occurs, cerebral edema is seen to be caused by a disturbance in cerebral blood flow. However, it is unclear and unproven whether venous spasm occurs after subarachnoid hemorrhage (SAH). To provide the theoretical basis for treating cerebral vasospasm after SAH, magnetic resonance imaging (MRI) was employed to observe the changes in the diameter of deep cerebral veins in rabbits after SAH. Methods Fourteen New Zealand rabbits were randomly divided into the SAH group (n = 10) and the normal saline group (NS group, n = 4). Specifically, the SAH models were established by the ultrasound-guided double injections of blood into cisterna magna. Moreover, the MRI was performed to observe the changes in the diameter of deep cerebral veins (internal cerebral vein, basilar vein, and great cerebral vein) and basilar artery before modeling (0 d) and 1, 3, 5, 7, 9, and 11 d after modeling. Results In the SAH group, the diameter of the basilar artery showed no evident change on the 1st d. However, it became narrower obviously on the 3rd d and 5th d, and the stenosis degree was more than 30%. The diameter gradually relieved from 7th to 9th d, and finally returned to normal on the 11th d. Moreover, the diameter of the internal cerebral vein significantly narrowed on the 1st d, the stenosis degree of which was 19%; the stenosis then relieved slightly on the 3rd d (13%), reached the peak (34%) on the 5th d, and gradually relieved from 7th d to 11th d. Moreover, the stenosis degree of the basilar vein was 18% on the 1st d, 24% on the 3rd d, and reached the peak (34%) on the 5th d. Conclusion After SAH in rabbits, the cerebral vasospasm was seen to occur in the basilar artery, and likewise, spasmodic changes took place in the deep cerebral vein. Furthermore, the time regularity of spasmodic changes between the cerebral vein and basilar artery was of significant difference, indicating that the venous vasospasm resulted in active contraction.
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Affiliation(s)
- Zixuan Zhang
- Department of Clinical Medicine, West Anhui Health Vocational College, Lu'an, China
- Department of Anatomy, Anhui Medical University, Hefei, China
| | - Qiong Fang
- Department of Basic Medicine, Anhui Medical College, Hefei, China
| | - Yu Zhang
- Department of Radiology, The 901st Hospital of the Joint Logistics Support Force of PLA, Hefei, China
| | - Youzhi Zhu
- Department of Radiology, The 901st Hospital of the Joint Logistics Support Force of PLA, Hefei, China
| | - Wei Zhang
- Department of Anatomy, Anhui Medical University, Hefei, China
| | - Youyou Zhu
- Department of Anatomy, Anhui Medical University, Hefei, China
| | - Xuefei Deng
- Department of Anatomy, Anhui Medical University, Hefei, China
- *Correspondence: Xuefei Deng
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5
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Tada S. COMPUTATIONAL STUDY OF THE INFLUENCE OF BIFURCATION ANGLE ON HAEMODYNAMICS AND OXYGEN TRANSPORT IN THE CAROTID BIFURCATION. BIOMEDICAL ENGINEERING: APPLICATIONS, BASIS AND COMMUNICATIONS 2019. [DOI: 10.4015/s1016237219500248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this study, blood flow associated with oxygen transport in the human carotid bifurcation was investigated numerically to assess the effects of bifurcation geometry on distribution and magnitude of the wall shear stress (WSS) and Sherwood number (Sh: dimensionless oxygen wall flux) at the favourable site of atherosclerotic lesion. Three-dimensional average models of the rigid-walled carotid bifurcation were constructed to perform simulations of steady blood flow under the wall boundary condition of a constant oxygen tension. The results demonstrated that changes in the bifurcation angle significantly altered the distribution of both the WSS and the Sh, even though the pattern of the axial flow was not very sensitive to the change in bifurcation angle. Flow with large inertia bifurcated at the flow divider and created a flow recirculation zone with low WSS and Sh on the outer wall of the internal carotid artery (ICA) sinus, where atherosclerotic lesions tend to develop. A wider bifurcation angle made the area of low Sh in the ICA sinus smaller, but the level of Sh along the outer wall of the ICA sinus extremely low. Another finding was that low Sh was associated with high WSS at the region distal to the ICA sinus. The Sh distribution did not readjust as fast as the WSS in this region, as reflected by the different rates of recovery of the WSS and Sh, thus uncoupling the transport process of oxygen transport from WSS.
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Affiliation(s)
- Shigeru Tada
- Department of Applied Physics, National Defence Academy, 1-10-20 Hashirimizu, Yokosuka, Kanagawa 239-8686, Japan
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6
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Agujetas R, González-Fernández MR, Nogales-Asensio JM, Montanero JM. Numerical analysis of the pressure drop across highly-eccentric coronary stenoses: application to the calculation of the fractional flow reserve. Biomed Eng Online 2018; 17:67. [PMID: 29848333 PMCID: PMC5977766 DOI: 10.1186/s12938-018-0503-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/23/2018] [Indexed: 11/29/2022] Open
Abstract
Background Fractional flow reverse (FFR) is the gold standard assessment of the hemodynamic significance of coronary stenoses. However, it requires the catheterization of the coronary artery to determine the pressure waveforms proximal and distal to the stenosis. On the contrary, computational fluid dynamics enables the calculation of the FFR value from relatively non-invasive computed tomography angiography (CTA). Methods We analyze the flow across idealized highly-eccentric coronary stenoses by solving the Navier–Stokes equations. We examine the influence of several aspects (approximations) of the simulation method on the calculation of the FFR value. We study the effects on the FFR value of errors made in the segmentation of clinical images. For this purpose, we compare the FFR value for the nominal geometry with that calculated for other shapes that slightly deviate from that geometry. This analysis is conducted for a range of stenosis severities and different inlet velocity and pressure waveforms. Results and conclusions The errors made in assuming a uniform velocity profile in front of the stenosis, as well as those due to the Newtonian and laminar approximations, are negligible for stenosis severities leading to FFR values around the threshold 0.8. The limited resolution of the stenosis geometry reconstruction is the major source of error when predicting the FFR value. Both systematic errors in the contour detection of just 1-pixel size in the CTA images and a low-quality representation of the stenosis surface (coarse faceted geometry) may yield wrong outcomes of the FFR assessment for an important set of eccentric stenoses. On the contrary, the spatial resolution of images acquired with optical coherence tomography may be sufficient to ensure accurate predictions for the FFR value.
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Affiliation(s)
- R Agujetas
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain
| | - M R González-Fernández
- Servicio de Cardiología, Hospital Infanta Cristina, Avda. de Elvas s/n, 06006, Badajoz, Spain
| | - J M Nogales-Asensio
- Servicio de Cardiología, Hospital Infanta Cristina, Avda. de Elvas s/n, 06006, Badajoz, Spain
| | - J M Montanero
- Depto. de Ingeniería Mecánica, Energética y de los Materiales and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, Avda. de Elvas s/n, 06006, Badajoz, Spain.
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7
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Madhavan S, Kemmerling EMC. The effect of inlet and outlet boundary conditions in image-based CFD modeling of aortic flow. Biomed Eng Online 2018; 17:66. [PMID: 29843730 PMCID: PMC5975715 DOI: 10.1186/s12938-018-0497-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 05/10/2018] [Indexed: 11/10/2022] Open
Abstract
Background Computational modeling of cardiovascular flow is a growing and useful field, but such simulations usually require the researcher to guess the flow’s inlet and outlet conditions since they are difficult and expensive to measure. It is critical to determine the amount of uncertainty introduced by these assumptions in order to evaluate the degree to which cardiovascular flow simulations are accurate. Our work begins to address this question by examining the sensitivity of flow to several different assumed velocity inlet and outlet conditions in a patient-specific aorta model. Methods We examined the differences between plug flow, parabolic flow, linear shear flows, skewed cubic flow profiles, and Womersley flow at the inlet. Only the shape of the inlet velocity profile was varied—all other parameters were identical among these simulations. Secondary flow in the form of a counter-rotating pair of vortices was also added to parabolic axial flow to study its effect on the solution. In addition, we examined the differences between two-element Windkessel, three element Windkessel and the outflow boundary conditions. In these simulations, only the outlet boundary condition was varied. Results The results show axial and in-plane velocities are considerably different close to the inlet for the cases with different inlet velocity profile shapes. However, the solutions are qualitatively similar beyond 1.75D, where D is the inlet diameter. This trend is also observed in other quantities such as pressure and wall shear stress. Normalized root-mean-square deviation, a measure of axial velocity magnitude differences between the different cases, generally decreases along the streamwise coordinate. The linear shear inlet velocity boundary condition and plug velocity boundary condition solution exhibit the highest time-averaged wall shear stress, approximately \documentclass[12pt]{minimal}
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\begin{document}$$8\%$$\end{document}8% higher than the parabolic inlet velocity boundary condition. Upstream of 1D from the inlet, adding secondary flow has a significant impact on temporal wall shear stress distributions. This is especially observable during diastole, when integrated wall shear stress magnitude varies about \documentclass[12pt]{minimal}
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\begin{document}$$26\%$$\end{document}26% between simulations with and without secondary flow. The results from the outlet boundary condition study show the Windkessel models differ from the outflow boundary condition by as much as \documentclass[12pt]{minimal}
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\begin{document}$$18\%$$\end{document}18% in terms of time-averaged wall shear stress. Furthermore, normalized root-mean-square deviation of axial velocity magnitude, a measure of deviation between Windkessel and the outflow boundary condition, increases along the streamwise coordinate indicating larger variations near outlets. Conclusion It was found that the selection of inlet velocity conditions significantly affects only the flow region close to the inlet of the aorta. Beyond two diameters distal to the inlet, differences in flow solution are small. Although additional studies must be performed to verify this result, the data suggest that it is important to use patient-specific inlet conditions primarily if the researcher is concerned with the details of the flow very close to the inlet. Similarly, the selection of outlet conditions significantly affects the flow in the vicinity of the outlets. Upstream of five diameters proximal to the outlet, deviations between the outlet boundary conditions examined are insignificant. Although the inlet and outlet conditions only affect the flow significantly in their respective neighborhoods, our study indicates that outlet conditions influence a larger percentage of the solution domain.
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Affiliation(s)
- Sudharsan Madhavan
- Department of Mechanical Engineering, Tufts University, 200 College Avenue, Medford, MA, 02155, USA.
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8
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Park JIK, Heikhmakhtiar AK, Kim CH, Kim YS, Choi SW, Song KS, Lim KM. The effect of heart failure and left ventricular assist device treatment on right ventricular mechanics: a computational study. Biomed Eng Online 2018; 17:62. [PMID: 29784052 PMCID: PMC5963151 DOI: 10.1186/s12938-018-0498-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 05/10/2018] [Indexed: 11/23/2022] Open
Abstract
Background and aims Although it is important to analyze the hemodynamic factors related to the right ventricle (RV) after left ventricular assist device (LVAD) implantation, previous studies have focused only on the alteration of the ventricular shape and lack quantitative analysis of the various hemodynamic parameters. Therefore, we quantitatively analyzed various hemodynamic parameters related to the RV under normal, heart failure (HF), and HF incorporated with continuous flow LVAD therapy by using a computational model. Methods In this study, we combined a three-dimensional finite element electromechanical model of ventricles, which is based on human ventricular morphology captured by magnetic resonance imaging (MRI) with a lumped model of the circulatory system and continuous flow LVAD function in order to construct an integrated model of an LVAD implanted-cardiovascular system. To induce systolic dysfunction, the magnitude of the calcium transient function under HF condition was reduced to 70% of the normal value, and the time constant was reduced by 30% of the normal value. Results Under the HF condition, the left ventricular end systolic pressure decreased, the left ventricular end diastolic pressure increased, and the pressure in the right atrium (RA), RV, and pulmonary artery (PA) increased compared with the normal condition. The LVAD therapy decreased the end-systolic pressure of the LV by 41%, RA by 29%, RV by 53%, and PA by 71%, but increased the right ventricular ejection fraction by 52% and cardiac output by 40%, while the stroke work was reduced by 67% compared with the HF condition without LVAD. The end-systolic ventricular tension and strain decreased with the LVAD treatment. Conclusion LVAD enhances CO and mechanical unloading of the LV as well as those of the RV and prevents pulmonary hypertension which can be induced by HF.
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Affiliation(s)
- Jun I K Park
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea
| | - Aulia Khamas Heikhmakhtiar
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea
| | - Chang Hyun Kim
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea
| | - Yoo Seok Kim
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea
| | - Seong Wook Choi
- Department of Mechanical & Biomedical Engineering, Kangwon National University, Kangwon, Republic of Korea
| | - Kwang Soup Song
- Department of Medical IT Convergence Engineering, Kumoh National Institute of Technology, Gumi, Republic of Korea
| | - Ki Moo Lim
- Department of IT Convergence Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk, 39177, Republic of Korea.
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Gu K, Zhang Z, Gao B, Chang Y, Wan F. Hemodynamic effects of perfusion level of peripheral ECMO on cardiovascular system. Biomed Eng Online 2018; 17:59. [PMID: 29743080 PMCID: PMC5944029 DOI: 10.1186/s12938-018-0493-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 05/02/2018] [Indexed: 02/06/2023] Open
Abstract
Background Peripheral ECMO is an effective cardiopulmonary support in clinical. The perfusion level could directly influence the performances and complications. However, there are few studies on the effects of the perfusion level on hemodynamics of peripheral ECMO. Methods The geometric model of cardiovascular system with peripheral ECMO was established. The blood assist index was used to classify the perfusion level of the ECMO. The flow pattern from the aorta to the femoral artery and their branches, blood flow rate from aorta to brain and limbs, flow interface, harmonic index of blood flow, wall shear stress and oscillatory shear index were chosen to evaluate the hemodynamic effects of peripheral ECMO. Results The results demonstrated that the flow rate of aorta outlets increased and perfusion condition had been improved. And the average flow to the upper limbs and brain has a positive correlation with BAI (r = 0.037, p < 0.05), while there is a negative correlation with lower limbs (r = − 0.054, p < 0.05). The HI has negative correlation with BAI (p < 0.05, r < 0). The blood interface is further from the heart with the BAI decrease. And the average WSS has negative correlation with BAI (p < 0.05, r = − 0.983) at the bifurcation of femoral aorta and has positive correlation with BAI (p < 0.05, r = 0.99) at the inner aorta. The OSI under different BAI is higher (reaching 0.4) at the inner wall of the aortic arch, the descending aorta and the femoral access. Conclusions The pathogenesis of peripheral ECMO with different perfusion levels varies; its further research will be thorough and extensive.
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Affiliation(s)
- Kaiyun Gu
- Peking University Third Hospital, 49 North Garden Rd., Haidian District, Beijing, 100191, China.,Peking University Health Science Center, Xueyuan Rd, Haidian District, Beijing, 100083, China
| | - Zhe Zhang
- Peking University Third Hospital, 49 North Garden Rd., Haidian District, Beijing, 100191, China.
| | - Bin Gao
- College of Life Science & Bio-Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Yu Chang
- College of Life Science & Bio-Engineering, Beijing University of Technology, Beijing, 100124, China.
| | - Feng Wan
- Peking University Third Hospital, 49 North Garden Rd., Haidian District, Beijing, 100191, China.,Peking University Health Science Center, Xueyuan Rd, Haidian District, Beijing, 100083, China
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10
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Zhu Y, Chen R, Juan YH, Li H, Wang J, Yu Z, Liu H. Clinical validation and assessment of aortic hemodynamics using computational fluid dynamics simulations from computed tomography angiography. Biomed Eng Online 2018; 17:53. [PMID: 29720173 PMCID: PMC5932836 DOI: 10.1186/s12938-018-0485-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 04/23/2018] [Indexed: 02/02/2023] Open
Abstract
Background Hemodynamic information including peak systolic pressure (PSP) and peak systolic velocity (PSV) carry an important role in evaluation and diagnosis of congenital heart disease (CHD). Since MDCTA cannot evaluate hemodynamic information directly, the aim of this study is to provide a noninvasive method based on a computational fluid dynamics (CFD) model, derived from multi-detector computed tomography angiography (MDCTA) raw data, to analyze the aortic hemodynamics in infants with CHD, and validate these results against echocardiography and cardiac catheter measurements. Methods This study included 25 patients (17 males, and 8 females; a median age of 2 years, range: 4 months–4 years) with CHD. All patients underwent both transthoracic echocardiography (TTE) and MDCTA within 2 weeks prior to cardiac catheterization. CFD models were created from MDCTA raw data. Boundary conditions were confirmed by lumped parameter model and transthoracic echocardiography (TTE). Peak systolic velocity derived from CFD models (PSVCFD) was compared to TTE measurements (PSVTTE), while the peak systolic pressure derived from CFD (PSPCFD) was compared to catheterization (PSPCC). Regions with low and high peak systolic wall shear stress (PSWSS) were also evaluated. Results PSVCFD and PSPCFD showed good agreements between PSVTTE (r = 0.968, p < 0.001; mean bias = − 7.68 cm/s) and PSPCC (r = 0.918, p < 0.001; mean bias = 1.405 mmHg). Regions with low and high PSWSS) can also be visualized. Skewing of velocity or helical blood flow was also observed at aortic arch in patients. Conclusions Our result demonstrated that CFD scheme based on MDCTA raw data is an accurate and convenient method in obtaining the velocity and pressure from aorta and displaying the distribution of PSWSS and flow pattern of aorta. The preliminary results from our study demonstrate the capability in combining clinical imaging data and novel CFD tools in infants with CHD and provide a noninvasive approach for diagnose of CHD such as coarctation of aorta in future.
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Affiliation(s)
- Yulei Zhu
- Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, No. 106, Zhong Shan Er Lu, Guangzhou, 510080, Guangdong, China.,School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong, China
| | - Rui Chen
- Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, No. 106, Zhong Shan Er Lu, Guangzhou, 510080, Guangdong, China.,School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong, China
| | - Yu-Hsiang Juan
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou Chang Gung University, Taoyuan, Taiwan
| | - He Li
- Department of Cardiac Surgery, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong General Hospital, Guangdong Academy of Medical Sciences, No. 106, Zhong Shan Er Lu, Guangzhou, 510080, Guangdong, China
| | - Jingjing Wang
- Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, No. 106, Zhong Shan Er Lu, Guangzhou, 510080, Guangdong, China.,School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong, China
| | - Zhuliang Yu
- School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong, China. .,College of Automation Science and Technology, South China University of Technology, 381 Wushan Road, Guangzhou, 510080, Guangdong, China.
| | - Hui Liu
- Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, No. 106, Zhong Shan Er Lu, Guangzhou, 510080, Guangdong, China. .,School of Medicine, South China University of Technology, Guangzhou, 510006, Guangdong, China.
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11
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González-Suárez A, Pérez JJ, Berjano E. Should fluid dynamics be included in computer models of RF cardiac ablation by irrigated-tip electrodes? Biomed Eng Online 2018; 17:43. [PMID: 29678186 PMCID: PMC5910590 DOI: 10.1186/s12938-018-0475-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 04/16/2018] [Indexed: 11/10/2022] Open
Abstract
Background Although accurate modeling of the thermal performance of irrigated-tip electrodes in radiofrequency cardiac ablation requires the solution of a triple coupled problem involving simultaneous electrical conduction, heat transfer, and fluid dynamics, in certain cases it is difficult to combine the software with the expertise necessary to solve these coupled problems, so that reduced models have to be considered. We here focus on a reduced model which avoids the fluid dynamics problem by setting a constant temperature at the electrode tip. Our aim was to compare the reduced and full models in terms of predicting lesion dimensions and the temperatures reached in tissue and blood. Results The results showed that the reduced model overestimates the lesion surface width by up to 5 mm (i.e. 70%) for any electrode insertion depth and blood flow rate. Likewise, it drastically overestimates the maximum blood temperature by more than 15 °C in all cases. However, the reduced model is able to predict lesion depth reasonably well (within 0.1 mm of the full model), and also the maximum tissue temperature (difference always less than 3 °C). These results were valid throughout the entire ablation time (60 s) and regardless of blood flow rate and electrode insertion depth (ranging from 0.5 to 1.5 mm). Conclusions The findings suggest that the reduced model is not able to predict either the lesion surface width or the maximum temperature reached in the blood, and so would not be suitable for the study of issues related to blood temperature, such as the incidence of thrombus formation during ablation. However, it could be used to study issues related to maximum tissue temperature, such as the steam pop phenomenon.
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Affiliation(s)
- Ana González-Suárez
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Carrer Roc Boronat 138, 08018, Barcelona, Spain.
| | - Juan J Pérez
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
| | - Enrique Berjano
- BioMIT, Department of Electronic Engineering, Universitat Politècnica de València, Valencia, Spain
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12
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Xie X, Zheng M, Wen D, Li Y, Xie S. A new CFD based non-invasive method for functional diagnosis of coronary stenosis. Biomed Eng Online 2018; 17:36. [PMID: 29566702 PMCID: PMC5863834 DOI: 10.1186/s12938-018-0468-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 03/17/2018] [Indexed: 02/07/2023] Open
Abstract
Background Accurate functional diagnosis of coronary stenosis is vital for decision making in coronary revascularization. With recent advances in computational fluid dynamics (CFD), fractional flow reserve (FFR) can be derived non-invasively from coronary computed tomography angiography images (FFRCT) for functional measurement of stenosis. However, the accuracy of FFRCT is limited due to the approximate modeling approach of maximal hyperemia conditions. To overcome this problem, a new CFD based non-invasive method is proposed. Methods Instead of modeling maximal hyperemia condition, a series of boundary conditions are specified and those simulated results are combined to provide a pressure-flow curve for a stenosis. Then, functional diagnosis of stenosis is assessed based on parameters derived from the obtained pressure-flow curve. Results The proposed method is applied to both idealized and patient-specific models, and validated with invasive FFR in six patients. Results show that additional hemodynamic information about the flow resistances of a stenosis is provided, which cannot be directly obtained from anatomy information. Parameters derived from the simulated pressure-flow curve show a linear and significant correlations with invasive FFR (r > 0.95, P < 0.05). Conclusion The proposed method can assess flow resistances by the pressure-flow curve derived parameters without modeling of maximal hyperemia condition, which is a new promising approach for non-invasive functional assessment of coronary stenosis.
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Affiliation(s)
- Xinzhou Xie
- Department of Electronic Science and Technology, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi, People's Republic of China.
| | - Minwen Zheng
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi'an, Shaanxi, People's Republic of China
| | - Didi Wen
- Department of Radiology, Xijing Hospital, Fourth Military Medical University, 15 West Changle Road, Xi'an, Shaanxi, People's Republic of China
| | - Yabing Li
- Department of Electronic Science and Technology, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi, People's Republic of China
| | - Songyun Xie
- Department of Electronic Science and Technology, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, Shaanxi, People's Republic of China
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13
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Tavallali P, Koorehdavoudi H, Krupa J. Intrinsic Frequency Analysis and Fast Algorithms. Sci Rep 2018; 8:4858. [PMID: 29559648 PMCID: PMC5861104 DOI: 10.1038/s41598-018-22907-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 03/01/2018] [Indexed: 12/16/2022] Open
Abstract
Intrinsic Frequency (IF) has recently been introduced as an ample signal processing method for analyzing carotid and aortic pulse pressure tracings. The IF method has also been introduced as an effective approach for the analysis of cardiovascular system dynamics. The physiological significance, convergence and accuracy of the IF algorithm has been established in prior works. In this paper, we show that the IF method could be derived by appropriate mathematical approximations from the Navier-Stokes and elasticity equations. We further introduce a fast algorithm for the IF method based on the mathematical analysis of this method. In particular, we demonstrate that the IF algorithm can be made faster, by a factor or more than 100 times, using a proper set of initial guesses based on the topology of the problem, fast analytical solution at each point iteration, and substituting the brute force algorithm with a pattern search method. Statistically, we observe that the algorithm presented in this article complies well with its brute-force counterpart. Furthermore, we will show that on a real dataset, the fast IF method can draw correlations between the extracted intrinsic frequency features and the infusion of certain drugs.
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Affiliation(s)
- Peyman Tavallali
- Division of Engineering and Applied Sciences, California Institute of Technology, 1200 East California Boulevard, MC 205-45, Pasadena, CA, 91125, USA. .,Avicena LLC, 2400 N Lincoln Ave, Altadena, CA, 91001, USA.
| | - Hana Koorehdavoudi
- Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA, 90089-1453, USA.,Avicena LLC, 2400 N Lincoln Ave, Altadena, CA, 91001, USA
| | - Joanna Krupa
- Avicena LLC, 2400 N Lincoln Ave, Altadena, CA, 91001, USA
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14
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Niu L, Zhu X, Pan M, Derek A, Xu L, Meng L, Zheng H. Influence of vascular geometry on local hemodynamic parameters: phantom and small rodent study. Biomed Eng Online 2018; 17:30. [PMID: 29499760 PMCID: PMC5833153 DOI: 10.1186/s12938-018-0458-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 02/21/2018] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Many studies have demonstrated that the geometry of the carotid bifurcation enables prediction of blood flow variation associated with atherosclerotic plaque formation. The phase angle between the arterial wall circumferential strain and its instantaneous wall shear stress is known as stress phase angle (SPA). This parameter is used to evaluate hemodynamic factors of atherogenesis. Note that SPA can be numerically computed for the purpose of locating atherosclerosis in different artery geometries. However, there is no experimental data to verify its role in the location of atherosclerosis in different artery geometries. In this study, we use an ultrasonic biomechanical method to experimentally evaluate the role of SPA for locating atherosclerosis in carotid bifurcation. RESULTS For carotid anthropomorphic vascular phantom experiments, the SPAs of common carotid arteries (CCAs), external carotid arteries (ECAs) and internal carotid arteries (ICAs) are - 148.53 ± 6.92°, - 153.95 ± 5.11°, and - 238.69 ± 1.72°, respectively. The corresponding SPAs are - 173.47 ± 0.065°, - 115.57 ± 4.83° and - 233.9 ± 8.12° for the polyvinyl alcohol (PVA-c) phantoms. In vivo mouse experiments indicated that the wall shear stress and circumferential strain were out of phase in the ICAs (- 280.08 ± 13.12°) to a greater extent as compared to CCAs (- 141.97 ± 8.03°) and ECAs (- 170.07 ± 9.24°). CONCLUSIONS The results suggested that SPA may be a useful indicator to locate the atherosclerosis position in carotid bifurcation.
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Affiliation(s)
- Lili Niu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
| | - Xiliang Zhu
- Department of Cardiovascular Surgery, Henan Province People's Hospital, Fuwai Central China Cardiovascular Hospital, Zhengzhou University People's Hospital and Medical School of Henan University, Zhengzhou, 450000, Henan Province, People's Republic of China
| | - Min Pan
- Guangzhou University of Chinese Medicine, Guangzhou, People's Republic of China
| | - Abbott Derek
- Centre for Biomedical Engineering, School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, Australia
| | - Lisheng Xu
- Sino-Dutch Biomedical and Information Engineering School, Northeastern University, 195 Chuangxin Ave., Hunnan District, Shenyang, 110819, People's Republic of China. .,Key Laboratory of Medical Image Computing, Ministry of Education, Northeastern University, Shenyang, China.
| | - Long Meng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China.
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
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15
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Rahmani S, Jarrahi A, Navidbakhsh M, Alizadeh M. Investigating the performance of four specific types of material grafts and their effects on hemodynamic patterns as well as on von Mises stresses in a grafted three-layer aortic model using fluid-structure interaction analysis. J Med Eng Technol 2017; 41:630-643. [PMID: 29076377 DOI: 10.1080/03091902.2017.1382590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
One of the important parts of the cardiac system is aorta which is the fundamental channel and supply of oxygenated blood in the body. Diseases of the aorta represent critical cardiovascular bleakness and mortality around the world. This study aims at investigation of hemodynamic parameters in a two-dimensional axisymmetric model of three-layer grafted aorta using fluid-structure interaction (FSI). It assumes that a damaged part of aorta, which may happen as a result of some diseases like aneurysm, dissection and post-stenotic dilatation, is replaced with a biomaterial graft. Four types of grafts materials so-called Polyurethane, Silicone rubber, Polytetrafluoroethylene (PTFE) and Dacron are considered in the present study. The assumption of linear elastic and isotropic material is set for the both aorta's wall and aforementioned grafts. Blood is considered as an incompressible and Newtonian fluid. The results indicate higher displacement in Polyurethane and silicone rubber in comparison with other two. Furthermore, results reveal that blood flow velocity has slightly higher values in PTFE and Dacron grafted models compared to Polyurethane and Silicone rubber ones. Even though there are some differences in hemodynamic patterns in these grafted models, they are not considerable as much as von Mises stresses across the graft-aorta intersections are. This study shows that the types of material grafts play an important role in the amount of stresses particularly at intersections of aorta and graft.
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Affiliation(s)
- Shahrokh Rahmani
- a School of Mechanical Engineering , Iran University of Science and Technology , Tehran , Iran
| | - Amin Jarrahi
- a School of Mechanical Engineering , Iran University of Science and Technology , Tehran , Iran
| | - Mahdi Navidbakhsh
- a School of Mechanical Engineering , Iran University of Science and Technology , Tehran , Iran
| | - Mansour Alizadeh
- a School of Mechanical Engineering , Iran University of Science and Technology , Tehran , Iran
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16
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Zhou H, Meng L, Zhou W, Xin L, Xia X, Li S, Zheng H, Niu L. Computational and experimental assessment of influences of hemodynamic shear stress on carotid plaque. Biomed Eng Online 2017; 16:92. [PMID: 28755660 PMCID: PMC5534247 DOI: 10.1186/s12938-017-0386-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/22/2017] [Indexed: 12/15/2022] Open
Abstract
Background Studies have identified hemodynamic shear stress as an important determinant of endothelial function and atherosclerosis. In this study, we assess the influences of hemodynamic shear stress on carotid plaques. Methods Carotid stenosis phantoms with three severity (30, 50, 70%) were made from 10% polyvinyl alcohol (PVA) cryogel. The phantoms were placed in a pulsatile flow loop with the same systolic/diastolic phase (35/65) and inlet flow rate (16 L/h). Ultrasonic particle imaging velocimetry (Echo PIV) and computational fluid dynamics (CFD) were used to calculate the velocity profile and shear stress distribution in the carotid stenosis phantoms. Inlet/outlet boundary conditions used in CFD were extracted from Echo PIV experiments to make sure that the results were comparable. Results Echo PIV and CFD results showed that velocity was largest in 70% than those in 30 and 50% at peak systole. Echo PIV results indicated that shear stress was larger in the upper wall and the surface of plaque than in the center of vessel. CFD results demonstrated that wall shear stress in the upstream was larger than in downstream of plaque. There was no significant difference in average velocity obtained by CFD and Echo PIV in 30% (p = 0.25). Velocities measured by CFD in 50% (93.01 cm/s) and in 70% (115.07 cm/s) were larger than those by Echo PIV in 50% (60.26 ± 5.36 cm/s) and in 70% (89.11 ± 7.21 cm/s). Conclusions The results suggested that Echo PIV and CFD could obtain hemodynamic shear stress on carotid plaques. Higher WSS occurred in narrower arteries, and the shoulder of plaque bore higher WSS than in bottom part.
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Affiliation(s)
- Hui Zhou
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Long Meng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
| | - Wei Zhou
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
| | - Lin Xin
- Department of Cardiology, Guangzhou General Hospital of Guangzhou Military Region, PLA, Guangzhou, 510010, People's Republic of China
| | - Xiangxiang Xia
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
| | - Shuai Li
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China
| | - Lili Niu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Nanshan District, Shenzhen, 518055, People's Republic of China.
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