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Flow Resistance Analysis of Clinically Significant Portal Hypertension in Patients with Liver Cirrhosis. Can J Gastroenterol Hepatol 2022; 2022:9396371. [PMID: 36199982 PMCID: PMC9529497 DOI: 10.1155/2022/9396371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 07/01/2022] [Accepted: 09/02/2022] [Indexed: 11/18/2022] Open
Abstract
Cirrhosis-induced clinically significant portal hypertension (CSPH) is a fatal disease. Early detection of CSPH is vitally important to reduce the patients' mortality rate. In this study, combined with three-dimensional image construction technology and computational fluid dynamics (CFD), an image-based flow resistance analysis was proposed. The flow resistance analysis was performed for nine cirrhosis patients with CSPH and ten participants without liver diseases, respectively. The results showed that the flow resistance coefficient of the portal vein system in CSPH patients was significantly lower than that in the control group (0.97 ± 0.11 Pa/(mL/s) for CSPH patients; 1.80 ± 0.40 Pa/(mL/s) for the control group; P = 0.028). In contrast, although main portal vein dilation was found in CSPH patients, the cross-sectional area enlargement was not statistically significant (186.01 ± 57.48 mm2 for CSPH patients; 166.26 ± 33.74 mm2 for the control group; P = 0.39). The research outcomes indicated that the flow resistance analysis was more sensitive than the commonly used vessel size measurement in the detection of CSPH. In summary, we suggest using flow resistance analysis as a supplementary noninvasive method to detect cirrhosis patients with CSPH.
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Blagosklonova ER, Dolotova DD, Arkhipov IV, Polunina NA, Stepanov VN, Krylov VV, Gavrilov AV. [Mathematical modeling of high-flow extra-intracranial bypass in the treatment of a complex cerebral aneurysm]. ZHURNAL VOPROSY NEIROKHIRURGII IMENI N. N. BURDENKO 2022; 86:23-32. [PMID: 35758075 DOI: 10.17116/neiro20228603123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
BACKGROUND Intracranial aneurysms (IAs) pose a high risk of spontaneous subarachnoid hemorrhage. In the most complex cases, the only way to exclude the aneurysm from the circulation is to perform a high-flow extracranial-to-intracranial bypass, thus creating a new bloodstream. This avoids severe ischemic complications; however, it requires careful consideration of individual anatomy and hemodynamic parameters. Computational fluid dynamics (CFD) can be of great help in planning such a surgery by creating 3D patient-specific models of cerebral circulation. OBJECTIVE Assessment of the perspectivity of high-flow extracranial-to-intracranial bypass planning using computational modeling. MATERIAL AND METHODS In this research work, we have applied the CFD methods to a patient with a giant thrombosed IA of the internal carotid artery (ICA). Preoperative CTA images and Gamma Multivox workstation were used to create a 3D model with current geometry and three additional models: Normal anatomy (no IA), Occlusion (with ligated ICA), Virtual bypass (with bypass and ligated ICA). The postoperative data were also available. Boundary conditions were based on PC-MRI measurements. Calculation of hemodynamics was conducted with a finite element package ANSYS Workbench 19. RESULTS The results demonstrated an increase in the blood flow on the affected side by more than 70% after the virtual surgery and uniformity of flow distribution between the affected and contralateral sides, indicating that the treatment is likely to be efficient. Later, postoperative data confirmed that. CONCLUSION The study showed that virtual preoperative CFD modeling could significantly simplify and improve surgical planning.
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Affiliation(s)
| | - D D Dolotova
- Gammamed-Soft LLC, Moscow, Russia
- Veltischev Research Clinical Institute of Pediatrics - Pirogov Russian National Research Medical University, Moscow, Russia
| | - I V Arkhipov
- Gammamed-Soft LLC, Moscow, Russia
- Lomonosov Moscow State University, Moscow, Russia
| | - N A Polunina
- Evdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
- Sklifosovsky Research Institute for Emergency Care, Moscow, Russia
| | - V N Stepanov
- Sklifosovsky Research Institute for Emergency Care, Moscow, Russia
| | - V V Krylov
- Evdokimov Moscow State University of Medicine and Dentistry, Moscow, Russia
- Sklifosovsky Research Institute for Emergency Care, Moscow, Russia
| | - A V Gavrilov
- Gammamed-Soft LLC, Moscow, Russia
- Lomonosov Moscow State University, Moscow, Russia
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Liu J, Yu F, Zhang Y. MP-PIC simulation of blood cell movement through a LAD with high stenosis. POWDER TECHNOL 2020. [DOI: 10.1016/j.powtec.2019.05.076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Liu J, Yu F, Zhang Y. Flow resistance coefficient analysis of left anterior descending artery stenosis: A preliminary study. Proc Inst Mech Eng H 2019; 234:100-109. [PMID: 31714179 DOI: 10.1177/0954411919887947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As a non-invasive diagnosis method, computed tomographic angiography–based computational fluid dynamics is used to estimate fractional flow reserve of coronary arteries (FFRct). However, FFRct uses hypothetical hemodynamic flow conditions, and thus FFRct might cause mismatches (fractional flow reserve > 0.8) with invasive fractional flow reserve (≤0.8). Additional computational fluid dynamics–based criteria are still needed to improve the accuracy of non-invasive diagnosis. In this article, a new concept of computed tomographic angiography–based flow resistance coefficient (FRCct) is proposed, and it tests pressure drops at coronary arteries under different blood flow rates and returns two constant flow resistance coefficients (A and B) for each artery. Specifically, 30 patients who were suspected to meet the treatment indication of their left anterior descending stenosis were tested with invasive fractional flow reserve and FRCct. The invasive fractional flow reserve divided the patients into a safe group (invasive fractional flow reserve > 0.8, 15 patients) and a sick group (invasive fractional flow reserve ≤ 0.8, 15 patients). A following FRCct indicated that the flow resistance coefficient always displayed a low value (A = 0.0039 ± 2.7e–5; B = 0.079 ± 0.0025) for the safe group, while the flow resistance coefficient always exhibited a high value (A = 0.0235 ± 0.001; B = 0.270 ± 0.108) for the sick group. The results of the statistical test indicated that the p-value was less than 0.05 for both A and B of the two groups. In conclusion, in addition to the FFRct, FRCct is a supplementary non-invasive method to evaluate the treatment indication of left anterior descending stenosis.
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Affiliation(s)
- Jian Liu
- Peking University People’s Hospital, Beijing, P.R. China
| | - Fan Yu
- Peking University People’s Hospital, Beijing, P.R. China
| | - Yu Zhang
- School of Medicine, Tsinghua University, Beijing, P.R. China
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Sia SF, Zhao X, Li R, Zhang Y, Chong W, He L, Chen Y. Evaluation of the carotid artery stenosis based on minimization of mechanical energy loss of the blood flow. Proc Inst Mech Eng H 2016; 230:1051-1058. [DOI: 10.1177/0954411916671752] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background: Internal carotid artery stenosis requires an accurate risk assessment for the prevention of stroke. Although the internal carotid artery area stenosis ratio at the common carotid artery bifurcation can be used as one of the diagnostic methods of internal carotid artery stenosis, the accuracy of results would still depend on the measurement techniques. The purpose of this study is to propose a novel method to estimate the effect of internal carotid artery stenosis on the blood flow based on the concept of minimization of energy loss. Methods: Eight internal carotid arteries from different medical centers were diagnosed as stenosed internal carotid arteries, as plaques were found at different locations on the vessel. A computational fluid dynamics solver was developed based on an open-source code (OpenFOAM) to test the flow ratio and energy loss of those stenosed internal carotid arteries. For comparison, a healthy internal carotid artery and an idealized internal carotid artery model have also been tested and compared with stenosed internal carotid artery in terms of flow ratio and energy loss. Results: We found that at a given common carotid artery bifurcation, there must be a certain flow distribution in the internal carotid artery and external carotid artery, for which the total energy loss at the bifurcation is at a minimum; for a given common carotid artery flow rate, an irregular shaped plaque at the bifurcation constantly resulted in a large value of minimization of energy loss. Thus, minimization of energy loss can be used as an indicator for the estimation of internal carotid artery stenosis.
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Affiliation(s)
- Sheau Fung Sia
- Division of Neurosurgery, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Xihai Zhao
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Rui Li
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Yu Zhang
- Medical Center, Tsinghua University, Beijing, China
- Australian School of Advanced Medicine (ASAM), Macquarie University, Sydney, NSW, Australia
| | | | - Le He
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Yu Chen
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
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Zhu F, Karunanithi K, Qian Y, Mao Y, Xu B, Gu Y, Zhu W, Chen L, Wang Y, Pan H, Liao Y, Morgan M. Assessing surgical treatment outcome following superficial temporal artery to middle cerebral artery bypass based on computational haemodynamic analysis. J Biomech 2015; 48:4053-4058. [DOI: 10.1016/j.jbiomech.2015.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 09/29/2015] [Accepted: 10/01/2015] [Indexed: 10/22/2022]
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Karunanithi K, Lee CJ, Chong W, Qian Y. The influence of flow diverter’s angle of curvature across the aneurysm neck on its haemodynamics. Proc Inst Mech Eng H 2015; 229:560-9. [DOI: 10.1177/0954411915593303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flow diverter stents have provided a new method of endovascular reconstruction for large and complex aneurysms. Understanding the impact of the flow diverter’s angle of curvature across the neck and its metal coverage rate on the haemodynamics of aneurysm is crucial to maximize the mass flow reduction inside the aneurysm, post-deployment. The aim of this study is to understand the correlation between the angle of curvature of flow diverter across the aneurysm neck and the metal coverage rate, and the aneurysm’s haemodynamics, using computational fluid dynamics. Varying the flow diverter angle resulted in varying metal coverage rate across the aneurysm neck for two patient vessel geometries, A (straight artery) and B (curved artery) with aspect ratios of 3.1 and 2.9, respectively. The results indicate that there exists a relationship between the aneurysm’s haemodynamics and the flow diverter’s angle of curvature across its neck. Moreover, the calculations indicated that cases with a moderately curved flow diverter, with an associated metal coverage rate of 50%–60%, achieve maximum flow reduction inside the aneurysm due to a stable flow resistance in the direction normal to the blood flow.
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Affiliation(s)
- Kaavya Karunanithi
- Australian School of Advanced Medicine, Macquarie University, Macquarie Park, NSW, Australia
| | - Chang Joon Lee
- Australian School of Advanced Medicine, Macquarie University, Macquarie Park, NSW, Australia
| | | | - Yi Qian
- Australian School of Advanced Medicine, Macquarie University, Macquarie Park, NSW, Australia
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Unenhanced respiratory-gated magnetic resonance angiography (MRA) of renal artery in hypertensive patients using true fast imaging with steady-state precession technique compared with contrast-enhanced MRA. J Comput Assist Tomogr 2014; 38:700-4. [PMID: 24733000 DOI: 10.1097/rct.0000000000000094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE This study was aimed to evaluate the accuracy of "True Fast Imaging with Steady-State Precession" (TrueFISP) MR angiography (MRA) for diagnosis of renal arterial stenosis (RAS) in hypertensive patients. METHODS Twenty-two patients underwent both TrueFISP MRA and contrast-enhanced MRA (CE-MRA) on a 1.5-T MR imager. Volume of main renal arteries, length of maximal visible renal arteries, number of visualized branches, stenotic grade, and subjective quality were compared. Paired 2-tailed Student t test and Wilcoxon signed rank test were applied to evaluate the significance of these variables. RESULTS Volume of main renal arteries, length of maximal visible renal arteries, and number of branches indicated no significant difference between the 2 techniques (P > 0.05). Stenotic degree of 10 RAS was greater on CE-MRA than on TrueFISP MRA. Qualitative scores from TrueFISP MRA were higher than those from CE-MRA (P < 0.05). CONCLUSIONS TrueFISP MRA is a reliable and accurate method for evaluating RAS.
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Zhu FP, Zhang Y, Higurashi M, Xu B, Gu YX, Mao Y, Morgan MK, Qian Y. Haemodynamic analysis of vessel remodelling in STA-MCA bypass for Moyamoya disease and its impact on bypass patency. J Biomech 2014; 47:1800-5. [PMID: 24720886 DOI: 10.1016/j.jbiomech.2014.03.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 03/10/2014] [Accepted: 03/21/2014] [Indexed: 11/15/2022]
Abstract
The purpose of this study is to estimate the remodelling characteristics of STA-MCA bypass and its influence on patency via the use of computational fluid dynamic (CFD) technology. The reconstructed three-dimensional geometries from MRA were segmented to create computational domains for CFD simulations. Eleven patients, who underwent regular MRA both immediately following surgery and at the six months follow-up, were studied. The flow velocities at STA were measured via the use of quantitative MRA (QMRA) to validate simulation results. STA-MCA bypass patency was confirmed for each patient immediately following surgery. The simulation indicated that the remodelling of the arterial pedicle in nine patients was associated with a reduction in the resistance to flow through the bypass. For these cases, the modelling of a driving pressure of 10mmHg through the bypass at 6 months post-surgery resulted in a 50% greater blood flow than those found immediately following surgery. However, two patients were found to exhibit contradictory patterns of remodelling, in which a highly curved bending at the bypass immediately post-surgery underwent progression, with increased resistance to flow through the bypass at 6 months follow-up, thereby resulting in a modelled flow rate reduction of 50% and 25%, respectively. This study revealed that STA-MCA bypass has a characteristic remodelling that usually reduces flow resistance. The initial morphology of the bypass may have had a significant effect on the outcome of vessel remodelling.
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Affiliation(s)
- Feng-Ping Zhu
- Australian School of Advanced Medicine, Macquarie University, Sydney, Australia; Department of Neurosurgery, Hua Shan Hospital, Fudan University, Shanghai, China
| | - Yu Zhang
- Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
| | - Masakazu Higurashi
- Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
| | - Bin Xu
- Department of Neurosurgery, Hua Shan Hospital, Fudan University, Shanghai, China
| | - Yu-Xiang Gu
- Department of Neurosurgery, Hua Shan Hospital, Fudan University, Shanghai, China
| | - Ying Mao
- Department of Neurosurgery, Hua Shan Hospital, Fudan University, Shanghai, China.
| | | | - Yi Qian
- Australian School of Advanced Medicine, Macquarie University, Sydney, Australia.
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Zhang W, Qian Y, Lin J, Lv P, Karunanithi K, Zeng M. Hemodynamic analysis of renal artery stenosis using computational fluid dynamics technology based on unenhanced steady-state free precession magnetic resonance angiography: preliminary results. Int J Cardiovasc Imaging 2013; 30:367-75. [DOI: 10.1007/s10554-013-0345-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 12/01/2013] [Indexed: 12/01/2022]
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