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Tian Y, Li X, Zhang J, Zhao B, Liang F. Identifying hemodynamic factors associated with the rupture of anterior communicating artery aneurysms based on global modeling of blood flow in the cerebral artery network. Front Bioeng Biotechnol 2024; 12:1419519. [PMID: 38938980 PMCID: PMC11208462 DOI: 10.3389/fbioe.2024.1419519] [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: 04/18/2024] [Accepted: 05/28/2024] [Indexed: 06/29/2024] Open
Abstract
Anterior communicating artery (ACoA) aneurysms are more prone to rupture compared to aneurysms present in other cerebral arteries. We hypothesize that systemic blood flow in the cerebral artery network plays an important role in shaping intra-aneurysmal hemodynamic environment thereby affecting the rupture risk of ACoA aneurysms. The majority of existing numerical studies in this field employed local modeling methods where the physical boundaries of a model are confined to the aneurysm region, which, though having the benefit of reducing computational cost, may compromise the physiological fidelity of numerical results due to insufficient account of systemic cerebral arterial hemodynamics. In the present study, we firstly carried out numerical experiments to address the difference between the outcomes of local and global modeling methods, demonstrating that local modeling confined to the aneurysm region results in inaccurate predictions of hemodynamic parameters compared with global modeling of the ACoA aneurysm as part of the cerebral artery network. Motivated by this finding, we built global hemodynamic models for 40 ACoA aneurysms (including 20 ruptured and 20 unruptured ones) based on medical image data. Statistical analysis of the computed hemodynamic data revealed that maximum wall shear stress (WSS), minimum WSS divergence, and maximum WSS gradient differed significantly between the ruptured and unruptured ACoA aneurysms. Optimal threshold values of high/low WSS metrics were determined through a series of statistical tests. In the meantime, some morphological parameters of aneurysms, such as large nonsphericity index, aspect ratio, and bottleneck factor, were found to be associated closely with aneurysm rupture. Furthermore, multivariate logistic regression analyses were performed to derive models combining hemodynamic and morphological parameters for discriminating the rupture status of aneurysms. The capability of the models in rupture status discrimination was high, with the area under the receiver operating characteristic curve reaching up to 0.9. The findings of the study suggest that global modeling of the cerebral artery network is essential for reliable quantification of hemodynamics in ACoA aneurysms, disturbed WSS and irregular aneurysm morphology are associated closely with aneurysm rupture, and multivariate models integrating hemodynamic and morphological parameters have high potential for assessing the rupture risk of ACoA aneurysms.
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Affiliation(s)
- Yuqing Tian
- Department of Engineering Mechanics, School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao Li
- Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianjian Zhang
- Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bing Zhao
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fuyou Liang
- Department of Engineering Mechanics, School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Hydrodynamics (MOE), School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- State Key Laboratory of Ocean Engineering, School of Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
- World-Class Research Center “Digital Biodesign and Personalized Healthcare”, Sechenov First Moscow State Medical University, Moscow, Russia
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Yang H, Cho KC, Hong I, Kim Y, Kim YB, Kim JJ, Oh JH. Influence of circle of Willis modeling on hemodynamic parameters in anterior communicating artery aneurysms and recommendations for model selection. Sci Rep 2024; 14:8476. [PMID: 38605063 PMCID: PMC11009257 DOI: 10.1038/s41598-024-59042-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024] Open
Abstract
Computational fluid dynamics (CFD) has been utilized to calculate hemodynamic parameters in anterior communicating artery aneurysm (AComA), which is located at a junction between left and right A1 and A2 segments. However, complete or half circle of Willis (CoW) models are used indiscriminately. This study aims to suggest recommendations for determining suitable CoW model. Five patient-specific CoW models with AComA were used, and each model was divided into complete, left-half, and right-half models. After validating the CFD using a flow experiment, the hemodynamic parameters and flow patterns in five AComAs were compared. In four out of five cases, inflow from one A1 side had a dominant influence on the AComA, while both left and right A1 sides affected the AComA in the remaining case. Also, the average difference in time-averaged wall shear stress between the complete and half models for four cases was 4.6%, but it was 62% in the other case. The differences in the vascular resistances of left and right A1 and A2 segments greatly influenced the flow patterns in the AComA. These results may help to enhance clinicians' understanding of blood flow in the brain, leading to improvements in diagnosis and treatment of cerebral aneurysms.
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Affiliation(s)
- Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, 55 Hanyangdaehak-Ro, Sangnok-Gu, Ansan, 15588, Gyeonggi-Do, Korea
| | - Kwang-Chun Cho
- Department of Neurosurgery, College of Medicine, Yonsei University, Yongin Severance Hospital, Yongin, Gyeonggi-Do, Korea
| | - Ineui Hong
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, 55 Hanyangdaehak-Ro, Sangnok-Gu, Ansan, 15588, Gyeonggi-Do, Korea
| | - Yeonwoo Kim
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, 55 Hanyangdaehak-Ro, Sangnok-Gu, Ansan, 15588, Gyeonggi-Do, Korea
| | - Yong Bae Kim
- Department of Neurosurgery, College of Medicine, Yonsei University, Severance Hospital, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Korea
| | - Jung-Jae Kim
- Department of Neurosurgery, College of Medicine, Yonsei University, Severance Hospital, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Korea.
- Department of Anatomy, Graduate School of Medicine, Korea University, 13 Jongam-Ro, Seongbuk-Gu, Seoul, 02841, Korea.
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, 55 Hanyangdaehak-Ro, Sangnok-Gu, Ansan, 15588, Gyeonggi-Do, Korea.
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Yang H, Kim JJ, Kim YB, Cho KC, Oh JH. Investigation of paraclinoid aneurysm formation by comparing the combined influence of hemodynamic parameters between aneurysmal and non-aneurysmal arteries. J Cereb Blood Flow Metab 2023:271678X231218589. [PMID: 38051823 DOI: 10.1177/0271678x231218589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Numerous studies have evaluated the effects of hemodynamic parameters on aneurysm formation. However, the reasons why aneurysms do not initiate in intracranial arteries are still unclear. This study aimed to investigate the influence of hemodynamic parameters, wall shear stress (WSS) and strain, on aneurysm formation by comparing between aneurysmal and non-aneurysmal arteries. Fifty-eight patients with paraclinoid aneurysms on one side were enrolled. Based on magnetic resonance angiography, each patient's left and right internal carotid arteries (ICAs) were reconstructed. For a patient having an aneurysm on one side, the ICA with the paraclinoid aneurysm was defined as the aneurysmal artery after eliminating the aneurysm, whereas the opposite ICA without aneurysm was defined as the non-aneurysmal artery. Computational fluid dynamics and fluid-structure interaction analyses were then performed for both aneurysmal and non-aneurysmal arteries. Finally, the relationship between high hemodynamic parameters and aneurysm location was investigated. For aneurysmal arteries, high WSS and strain locations were well-matched with the aneurysm formation site. Also, considerable correlations between high WSS and strain locations were observed. However, there was no significant relationship between high hemodynamic parameters and aneurysm formation for non-aneurysmal arteries. The findings are helpful for understanding aneurysm formation mechanism and encouraging further relevant research.
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Affiliation(s)
- Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, Korea
| | - Jung-Jae Kim
- Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Yong Bae Kim
- Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Kwang-Chun Cho
- Department of Neurosurgery, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Korea
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, Korea
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Yang H, Cho KC, Kim JJ, Kim YB, Oh JH. New morphological parameter for intracranial aneurysms and rupture risk prediction based on artificial neural networks. J Neurointerv Surg 2023; 15:e209-e215. [PMID: 36163346 DOI: 10.1136/jnis-2022-019201] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/29/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND Numerous studies have evaluated the rupture risk of intracranial aneurysms using morphological parameters because of their good predictive capacity. However, the limitation of current morphological parameters is that they do not always allow evaluation of irregularities of intracranial aneurysms. The purpose of this study is to propose a new morphological parameter that can quantitatively describe irregularities of intracranial aneurysms and to evaluate its performance regarding rupture risk prediction. METHODS In a retrospective study, conventional morphological parameters (aspect ratio, bottleneck ratio, height-to-width ratio, volume to ostium ratio, and size ratio) and a newly proposed morphological parameter (mass moment of inertia) were calculated for 125 intracranial aneurysms (80 unruptured and 45 ruptured aneurysms). Additionally, hemodynamic parameters (wall shear stress and strain) were calculated using computational fluid dynamics and fluid-structure interaction. Artificial neural networks trained with each parameter were used for rupture risk prediction. RESULTS All components of the mass moment of inertia (Ixx, Iyy, and Izz) were significantly higher in ruptured cases than in unruptured cases (p values for Ixx, Iyy, and Izz were 0.032, 0.047, and 0.039, respectively). When the conventional morphological and hemodynamic parameters as well as the mass moment of inertia were considered together, the highest performance for rupture risk prediction was obtained (sensitivity 96.3%; specificity 85.7%; area under the receiver operating characteristic curve 0.921). CONCLUSIONS The mass moment of inertia would be a useful parameter for evaluating aneurysm irregularity and hence its risk of rupture. The new approach described here may help clinicians to predict the risk of aneurysm rupture more effectively.
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Affiliation(s)
- Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, Gyeonggi-do, Korea
| | - Kwang-Chun Cho
- Department of Neurosurgery, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Korea
| | - Jung-Jae Kim
- Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Yong Bae Kim
- Department of Neurosurgery, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, Gyeonggi-do, Korea
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Oh S, Song Y, Lim H, Ko Y, Park S. The influence of contralateral circulation on computational fluid dynamics of intracranial arteries: simulated versus measured flow velocities. Eur Radiol Exp 2023; 7:55. [PMID: 37735305 PMCID: PMC10513987 DOI: 10.1186/s41747-023-00370-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/17/2023] [Indexed: 09/23/2023] Open
Abstract
BACKGROUND This study aimed to retrospectively evaluate the influence of contralateral anterior circulation on computational fluid dynamics (CFD) of intracranial arteries, by comparing the CFD values of flow velocities in unilateral anterior circulation with the measured values from phase-contrast magnetic resonance angiography (PC-MRA). METHODS We analyzed 21 unilateral anterior circulation models without proximal stenosis from 15 patients who performed both time-of-flight MRA (TOF-MRA) and PC-MRA. CFD was performed with the inflow boundary condition of a pulsatile flow of the internal carotid artery (ICA) obtained from PC-MRA. The outflow boundary condition was given as atmospheric pressure. Simulated flow velocities of the middle cerebral artery (MCA) and anterior cerebral artery (ACA) from CFD were compared with the measured values from PC-MRA. RESULTS The velocities of MCA were shown to be more accurately simulated on CFD than those of ACA (Spearman correlation coefficient 0.773 and 0.282, respectively). In four models with severe stenosis or occlusion of the contralateral ICA, the CFD values of ACA velocities were significantly lower (< 50%) than those measured with PC-MRA. ACA velocities were relatively accurately simulated in the models including similar diameters of both ACAs. CONCLUSION It may be necessary to consider the flow condition of the contralateral anterior circulation in CFD of intracranial arteries, especially in the ACA. RELEVANCE STATEMENT Incorporating the flow conditions of the contralateral circulation is of clinical importance for an accurate prediction of a rupture risk in Acom aneurysms as the bidirectional flow and accurate velocity of both ACAs can significantly impact the CFD results. KEY POINTS • CFD simulations using unilateral vascular models were relatively accurate for MCA. • Contralateral ICA steno-occlusion resulted in an underestimation of CFD velocity in ACA. • Contralateral flow may need to be considered in CFD simulations of ACA.
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Affiliation(s)
- SuJeong Oh
- Soon Chun Hyang University College of Medicine, 59, Daesagwan-ro, Yongsan-gu, Seoul, 04401, Republic of Korea
| | - YunSun Song
- University of Ulsan College of Medicine, Asan Medical Center, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - HyunKyung Lim
- Soon Chun Hyang University College of Medicine, 59, Daesagwan-ro, Yongsan-gu, Seoul, 04401, Republic of Korea
| | - YoungBae Ko
- Institute of Industrial Technology, 89, Yangdaegiro-gil, Ipjang-myeon, Seobuk-gu, Cheonan-si, Chungcheongnam-do, 31056, Republic of Korea
| | - SungTae Park
- Soon Chun Hyang University College of Medicine, 59, Daesagwan-ro, Yongsan-gu, Seoul, 04401, Republic of Korea.
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Yang H, Cho KC, Kim JJ, Kim JH, Kim YB, Oh JH. Rupture risk prediction of cerebral aneurysms using a novel convolutional neural network-based deep learning model. J Neurointerv Surg 2023; 15:200-204. [PMID: 35140167 DOI: 10.1136/neurintsurg-2021-018551] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/24/2022] [Indexed: 01/14/2023]
Abstract
BACKGROUND Cerebral aneurysms should be treated before rupture because ruptured aneurysms result in serious disability. Therefore, accurate prediction of rupture risk is important and has been estimated using various hemodynamic factors. OBJECTIVE To suggest a new way to predict rupture risk in cerebral aneurysms using a novel deep learning model based on hemodynamic parameters for better decision-making about treatment. METHODS A novel convolutional neural network (CNN) model was used for rupture risk prediction retrospectively of 123 aneurysm cases. To include the effect of hemodynamic parameters into the CNN, the hemodynamic parameters were first calculated using computational fluid dynamics and fluid-structure interaction. Then, they were converted into images for training the CNN using a novel approach. In addition, new data augmentation methods were devised to obtain sufficient training data. A total of 53,136 images generated by data augmentation were used to train and test the CNN. RESULTS The CNNs trained with wall shear stress (WSS), strain, and combination images had area under the receiver operating characteristics curve values of 0.716, 0.741, and 0.883, respectively. Based on the cut-off values, the CNN trained with WSS (sensitivity: 0.5, specificity: 0.79) or strain (sensitivity: 0.74, specificity: 0.71) images alone was not highly predictive. However, the CNN trained with combination images of WSS and strain showed a sensitivity and specificity of 0.81 and 0.82, respectively. CONCLUSION CNN-based deep learning algorithm using hemodynamic factors, including WSS and strain, could be an effective tool for predicting rupture risk in cerebral aneurysms with good predictive accuracy.
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Affiliation(s)
- Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, Gyeonggi-do, Korea
| | - Kwang-Chun Cho
- Department of Neurosurgery, College of Medicine, Yonsei University, Yongin Severance Hospital, Yongin, Korea
| | - Jung-Jae Kim
- Department of Neurosurgery, College of Medicine, Yonsei University, Severance Hospital, Seoul, Korea
| | - Jae Ho Kim
- Department of Neurosurgery, College of Medicine, Chosun University, Chosun University Hospital, Gwangju, Korea
| | - Yong Bae Kim
- Department of Neurosurgery, College of Medicine, Yonsei University, Severance Hospital, Seoul, Korea
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, Gyeonggi-do, Korea
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Influence of blood viscosity models and boundary conditions on the computation of hemodynamic parameters in cerebral aneurysms using computational fluid dynamics. Acta Neurochir (Wien) 2023; 165:471-482. [PMID: 36624234 DOI: 10.1007/s00701-022-05467-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 12/21/2022] [Indexed: 01/11/2023]
Abstract
BACKGROUND Computational fluid dynamics (CFD) is widely used to calculate hemodynamic parameters that are known to influence cerebral aneurysms. However, the boundary conditions for CFD are chosen without any specific criteria. Our objective is to establish the recommendations for setting the analysis conditions for CFD analysis of the cerebral aneurysm. METHOD The plug and the Womersley flow were the inlet boundary conditions, and zero and pulsatile pressures were the outlet boundary conditions. In addition, the difference in the assumption of viscosity was analyzed with respect to the flow rate. The CFD process used in our research was validated using particle image velocimetry experiment data from Tupin et al.'s work to ensure the accuracy of the simulations. RESULTS It was confirmed that if the entrance length was sufficiently secured, the inlet and outlet boundary conditions did not affect the CFD results. In addition, it was observed that the difference in the hemodynamic parameter between Newtonian and non-Newtonian fluid decreased as the flow rate increased. Furthermore, it was confirmed that similar tendencies were evaluated when these recommendations were utilized in the patient-specific cerebral aneurysm models. CONCLUSIONS These results may help conduct standardized CFD analyses regardless of the research group.
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Xin S, Chen Y, Zhao B, Liang F. Combination of Morphological and Hemodynamic Parameters for Assessing the Rupture Risk of Intracranial Aneurysms: a Retrospective Study On Mirror Middle Cerebral Artery Aneurysms. J Biomech Eng 2022; 144:1135619. [PMID: 35147191 DOI: 10.1115/1.4053793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Indexed: 11/08/2022]
Abstract
Discordant findings were frequently reported by studies dedicated to exploring the association of morphological/hemodynamic factors with the rupture of intracranial aneurysms (IAs), probably owing to insufficient control of confounding factors. In this study, we aimed to minimize the influences of confounding factors by focusing IAs of interest on mirror aneurysms and, meanwhile, modeling IAs together with the cerebral arterial network to improve the physiological fidelity of hemodynamic simulation. 52 mirror aneurysms located at the middle cerebral artery (MCA) in 26 patients were retrospectively investigated. Numerical tests performed on two randomly selected patients demonstrated that over truncation of cerebral arteries proximal to the MCA during image-based model reconstruction led to uncertain changes in computed values of intra-aneurysmal hemodynamic parameters, which justified the minimal truncation strategy adopted in our study. Five morphological parameters (i.e., volume (V), height (H), dome area (DA), non-sphericity index (NSI), and size ratio (SR)) and two hemodynamic parameters (i.e., peak WSS (peakWSS), and pressure loss coefficient (PLc)) were found to differ significantly between the ruptured and unruptured aneurysms and proved by receiver operating characteristic (ROC) analysis to have potential value for differentiating the rupture status of aneurysm with the areas under curve (AUCs) ranging from 0.681 to 0.763. Integrating V, SR, peakWSS and PLc or some of them into regression models considerably improved the classification of aneurysms, elevating AUC up to 0.864, which indicates that morphological and hemodynamic parameters have complementary roles in assessing the risk of aneurysm rupture.
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Affiliation(s)
- Shangzhe Xin
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yongchun Chen
- Department of Radiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, Zhejiang
| | - Bing Zhao
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Fuyou Liang
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
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Kim S, Yang H, Hong I, Oh JH, Kim YB. Computational Study of Hemodynamic Changes Induced by Overlapping and Compacting of Stents and Flow Diverter in Cerebral Aneurysms. Front Neurol 2021; 12:705841. [PMID: 34408723 PMCID: PMC8365227 DOI: 10.3389/fneur.2021.705841] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/14/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: The flow diversion effect of an intracranial stent is closely related to its metal coverage rate (MCR). In this study, the flow diversion effects of Enterprise and low-profile visualized intraluminal support (LVIS) stents are compared with those of a Pipeline flow diverter, focusing on the MCR change. Moreover, the changes in the flow diversion effect caused by the additional manipulations of overlapping and compaction are verified using computational fluid dynamics (CFD) analysis. Methods: CFD analysis was performed using virtually generated stents mounted in an idealized aneurysm model. First, the flow diversion effects of single Enterprise, LVIS, and Pipeline devices were analyzed. The Enterprise and LVIS were sequentially overlapped and compared with a Pipeline, to evaluate the effect of stent overlapping. The effect of compacting a stent was evaluated by comparing the flow diversion effects of a single and two compacted LVIS with those of two overlapped, uncompacted LVIS and uncompacted and compacted Pipeline. Quantitative analysis was performed to evaluate the hemodynamic parameters of energy loss, average velocity, and inflow rate. Results: Statistically significant correlations were observed between the reduction rates of the hemodynamic parameters and MCR. The single LVIS without compaction induced a reduction in all the hemodynamic parameters comparable to those of the three overlapped Enterprise. Moreover, the two overlapped, uncompacted LVIS showed a flow diversion effect as large as that induced by the single uncompacted Pipeline. Compacted stents induced a better flow diversion effect than uncompacted stents. The single compacted LVIS induced a flow diversion effect similar to that induced by the two uncompacted LVIS or single uncompacted Pipeline. Conclusions: The MCR of a stent correlates with its flow diversion effect. Overlapping and compaction can increase the MCR of an intracranial stent and achieve a flow diversion effect as large as that observed with a flow diverter.
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Affiliation(s)
- Sunghan Kim
- Department of Neurosurgery, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.,Department of Neurosurgery, Severance Stroke Center, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, South Korea
| | - Ineui Hong
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, South Korea
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, Ansan, South Korea
| | - Yong Bae Kim
- Department of Neurosurgery, Severance Stroke Center, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
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Hemodynamic factor evaluation using computational fluid dynamics analysis for de novo bleb formation in unruptured intracranial aneurysms. Neurol Sci 2021; 43:1849-1857. [PMID: 34331615 PMCID: PMC8860802 DOI: 10.1007/s10072-021-05482-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/08/2021] [Indexed: 11/25/2022]
Abstract
Background Although bleb formation increases the risk of rupture of intracranial aneurysms, previous computational fluid dynamic (CFD) studies have been unable to identify robust causative hemodynamic factors, due to the morphological differences of prebleb aneurysm models and a small number of aneurysms with de novo bleb formation. This study investigated the influences of differences in the aneurysm-models and identify causative hemodynamic factors for de novo bleb formation. Materials and methods CFD analysis was conducted on three aneurysm models, actual prebleb, postbleb, and virtual prebleb models of two unruptured aneurysms with de novo bleb formation. A new multipoint method was introduced in this study. We evenly distributed points with a 0.5-mm distance on the aneurysm surface of the actual prebleb models (146 and 152 points in the individual aneurysm, respectively), and we statistically compared hemodynamics at the points in the areas with and without bleb formation (19 and 279 points, respectively). Results Visually, blebs formed on an aneurysm surface area with similar hemodynamic characteristics in the actual and virtual prebleb models. Statistical analysis using the multipoint method revealed that the de novo bleb formation area was significantly correlated with high pressure (p < 0.001), low wall shear stress (WSS) (p < 0.001), and the center of divergent WSS vectors (p = 0.025). Conclusions De novo bleb formation in intracranial aneurysms may occur in areas associated with the combination of high pressure, low WSS, and the center of divergent WSS vectors. The multipoint method is useful for statistical analysis of hemodynamics in a limited number of aneurysms.
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Kim JJ, Yang H, Kim YB, Oh JH, Cho KC. The quantitative comparison between high wall shear stress and high strain in the formation of paraclinoid aneurysms. Sci Rep 2021; 11:7947. [PMID: 33846487 PMCID: PMC8041878 DOI: 10.1038/s41598-021-87126-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 03/24/2021] [Indexed: 11/12/2022] Open
Abstract
In the hemodynamic study, computational fluid dynamics (CFD) analysis has shown that high wall shear stress (WSS) is an important parameter in cerebral aneurysm formation. However, CFD analysis is not more realistic than fluid–structure interaction (FSI) analysis given its lack of considering the involvement of vascular structures. To investigate the relationship between the hemodynamic parameters and the aneurysm formation, the locations of high WSS and high strain were extracted from the CFD and FSI analyses, respectively. Then the distances between the aneurysm formation site and the locations of high WSS or high strain were calculated. A total of 37 intracranial paraclinoid aneurysms were enrolled for quantitative comparison. Additionally, the dura mater was modeled to facilitate realistic results in FSI analysis. The average distance from the location of the aneurysm formation site to the high strain (1.74 mm \documentclass[12pt]{minimal}
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\begin{document}$$\pm $$\end{document}± 1.04 mm) was smaller than the average distance to the high WSS (3.33 mm \documentclass[12pt]{minimal}
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\begin{document}$$\pm $$\end{document}± 1.18 mm). The presence of dura mater also influenced the findings in the aneurysm formation site. High strain extracted by FSI analysis is an important hemodynamic factor related to the formation of cerebral aneurysms. Strain parameter could help to predict the formation of aneurysms and elucidate the appropriate treatment.
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Affiliation(s)
- Jung-Jae Kim
- Department of Neurosurgery, College of Medicine, Ewha Womans University, Ewha Womans University Seoul Hospital, Seoul, Korea
| | - Hyeondong Yang
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, 15588, Gyeonggi-do, Korea
| | - Yong Bae Kim
- Department of Neurosurgery, College of Medicine, Yonsei University, Severance Hospital, Seoul, Korea
| | - Je Hoon Oh
- Department of Mechanical Engineering and BK21 FOUR ERICA-ACE Center, Hanyang University, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan, 15588, Gyeonggi-do, Korea.
| | - Kwang-Chun Cho
- Department of Neurosurgery, College of Medicine, Catholic Kwandong University, International St. Mary's Hospital, Simgokro 100gil 25, Seo-gu, Incheon, Korea.
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Prediction of internal carotid artery aneurysm recurrence by pressure difference at the coil mass surface. Neuroradiology 2020; 63:593-602. [PMID: 32929545 PMCID: PMC7966142 DOI: 10.1007/s00234-020-02553-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/08/2020] [Indexed: 12/23/2022]
Abstract
PURPOSE A previous study on computational fluid dynamics reported that a high pressure difference (PD) at the surface of a coil mass is a strong predictor of aneurysm recurrence after coil embolization. PD was calculated using a virtual post-coiling model (VM), created by manually cutting the aneurysm by the flat plane from an anatomic model created with pre-coil embolization data; however, its credibility has not been fully evaluated. This study aims to clarify whether PD values calculated using the post-coiling model, which reflects the actual coil plane, are a strong predictor of aneurysm recurrence. METHODS Fifty internal carotid artery aneurysms treated with endovascular coil embolization were analyzed (7 recanalized, 43 stable). We created and subjected two post-coiling models, namely, VM and the real post-coiling model (RM), constructed from the post-coil embolization data. The relationship between PD and aneurysm recurrence was examined using these models. PD and its constituent three parameters were compared between VM and RM. RESULTS PD values calculated using RM showed significantly higher aneurysm recurrence in recurrence group than stable group (p < 0.001), and multivariate analysis showed that PD in RM (p = 0.02; odds ratio, 36.24) was significantly associated with aneurysm recurrence. The receiver operating characteristic analysis revealed that PD values accurately predicted aneurysm recurrence (area under the curve, 0.977; cutoff value, 3.08; sensitivity, 100%; specificity, 97.7%). All four parameters showed a significant correlation with VM and RM (p < 0.001). CONCLUSION Use of PD to predict recurrence after coil embolization can be clinically relevant.
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Four-Dimensional Flow Magnetic Resonance Imaging for Assessment of Velocity Magnitudes and Flow Patterns in The Human Carotid Artery Bifurcation: Comparison with Computational Fluid Dynamics. Diagnostics (Basel) 2019; 9:diagnostics9040223. [PMID: 31847224 PMCID: PMC6963916 DOI: 10.3390/diagnostics9040223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/22/2019] [Accepted: 12/12/2019] [Indexed: 11/17/2022] Open
Abstract
Purpose: Knowledge of the hemodynamics in the vascular system is important to understand and treat vascular pathology. The present study aimed to evaluate the hemodynamics in the human carotid artery bifurcation measured by four-dimensional (4D) flow magnetic resonance imaging (MRI) as compared to computational fluid dynamics (CFD). Methods: This protocol used MRI data of 12 healthy volunteers for the 3D vascular models and 4D flow MRI measurements for the boundary conditions in CFD simulation. We compared the velocities measured at the carotid bifurcation and the 3D velocity streamlines of the carotid arteries obtained by these two methods. Results: There was a good agreement for both maximum and minimum velocity values between the 2 methods for velocity magnitude at the bifurcation plane. However, on the 3D blood flow visualization, secondary flows, and recirculation regions are of poorer quality when visualized through the 4D flow MRI. Conclusion: 4D flow MRI and CFD show reasonable agreement in demonstrated velocity magnitudes at the carotid artery bifurcation. However, the visualization of blood flow at the recirculation regions and the assessment of secondary flow characteristics should be enhanced for the use of 4D flow MRI in clinical situations.
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Goubergrits L, Hellmeier F, Bruening J, Spuler A, Hege HC, Voss S, Janiga G, Saalfeld S, Beuing O, Berg P. Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH): uncertainty quantification of geometric rupture risk parameters. Biomed Eng Online 2019; 18:35. [PMID: 30909934 PMCID: PMC6434802 DOI: 10.1186/s12938-019-0657-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/19/2019] [Indexed: 03/04/2023] Open
Abstract
Background Geometric parameters have been proposed for prediction of cerebral aneurysm rupture risk. Predicting the rupture risk for incidentally detected unruptured aneurysms could help clinicians in their treatment decision. However, assessment of geometric parameters depends on several factors, including the spatial resolution of the imaging modality used and the chosen reconstruction procedure. The aim of this study was to investigate the uncertainty of a variety of previously proposed geometric parameters for rupture risk assessment, caused by variability of reconstruction procedures. Materials 26 research groups provided segmentations and surface reconstructions of five cerebral aneurysms as part of the Multiple Aneurysms AnaTomy CHallenge (MATCH) 2018. 40 dimensional and non-dimensional geometric parameters, describing aneurysm size, neck size, and irregularity of aneurysm shape, were computed. The medians as well as the absolute and relative uncertainties of the parameters were calculated. Additionally, linear regression analysis was performed on the absolute uncertainties and the median parameter values. Results A large variability of relative uncertainties in the range between 3.9 and 179.8% was found. Linear regression analysis indicates that some parameters capture similar geometric aspects. The lowest uncertainties < 6% were found for the non-dimensional parameters isoperimetric ratio, convexity ratio, and ellipticity index. Uncertainty of 2D and 3D size parameters was significantly higher than uncertainty of 1D parameters. The most extreme uncertainties > 80% were found for some curvature parameters. Conclusions Uncertainty analysis is essential on the road to clinical translation and use of rupture risk prediction models. Uncertainty quantification of geometric rupture risk parameters provided by this study may help support development of future rupture risk prediction models. Electronic supplementary material The online version of this article (10.1186/s12938-019-0657-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leonid Goubergrits
- Institute for Computational and Imaging Science in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Florian Hellmeier
- Institute for Computational and Imaging Science in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Jan Bruening
- Institute for Computational and Imaging Science in Cardiovascular Medicine, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | | | | | - Samuel Voss
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
| | - Gábor Janiga
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
| | - Sylvia Saalfeld
- Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
| | - Oliver Beuing
- Institute of Neuroradiology, University Hospital Magdeburg, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
| | - Philipp Berg
- Department of Fluid Dynamics and Technical Flows, University of Magdeburg, Magdeburg, Germany.,Forschungscampus STIMULATE, Magdeburg, Germany
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Shimano K, Serigano S, Ikeda N, Yuchi T, Shiratori S, Nagano H. Understanding of boundary conditions imposed at multiple outlets in computational haemodynamic analysis of cerebral aneurysm. ACTA ACUST UNITED AC 2019. [DOI: 10.17106/jbr.33.32] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Kenjiro Shimano
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Shota Serigano
- Graduate School of Integrative Science and Engineering, Tokyo City University
| | - Naoki Ikeda
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Tomoki Yuchi
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Suguru Shiratori
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
| | - Hideaki Nagano
- Department of Mechanical Systems Engineering, Faculty of Engineering, Tokyo City University
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Prediction of Thin-Walled Areas of Unruptured Cerebral Aneurysms through Comparison of Normalized Hemodynamic Parameters and Intraoperative Images. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3047181. [PMID: 30327776 PMCID: PMC6171254 DOI: 10.1155/2018/3047181] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/02/2018] [Indexed: 11/17/2022]
Abstract
Object Rupture of a cerebral aneurysm occurs mainly in a thin-walled area (TWA). Prediction of TWAs would help to assess the risk of rupture and select appropriate treatment strategy. There are several limitations of current prediction techniques for TWAs. To predict TWAs more accurately, HP should be normalized to minimize the influence of analysis conditions, and the effectiveness of normalized, combined hemodynamic parameters (CHPs) should be investigated with help of the quantitative color analysis of intraoperative images. Methods A total of 21 unruptured cerebral aneurysms in 19 patients were analyzed. A normalized CHP was newly suggested as a weighted average of normalized wall shear stress (WSS) and normalized oscillatory shear index (OSI). Delta E from International Commission on Illumination was used to more objectively quantify color differences in intraoperative images. Results CFD analysis results indicated that WSS and OSI were more predictive of TWAs than pressure (P<.001, P=.187, P=.970, respectively); these two parameters were selected to define the normalized CHP. The normalized CHP became more statistically significant (P<.001) as the weighting factor of normalized WSS increased and that of normalized OSI decreased. Locations with high CHP values corresponded well to those with high Delta E values (P<.001). Predicted TWAs based on the normalized CHP showed a relatively good agreement with intraoperative images (17 in 21 cases, 81.0%). Conclusion 100% weighting on the normalized WSS produced the most statistically significant result. The normalization scheme for WSS and OSI suggested in this work was validated using quantitative color analyses, rather than subjective judgments, of intraoperative images, and it might be clinically useful for predicting TWAs of unruptured cerebral aneurysms. The normalization scheme would also be integrated into further fluid-structure interaction analysis for more reliable estimation of the risk of aneurysm rupture.
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Nambu I, Misaki K, Uchiyama N, Mohri M, Suzuki T, Takao H, Murayama Y, Futami K, Kawamura T, Inoguchi Y, Matsuzawa T, Nakada M. High Pressure in Virtual Postcoiling Model is a Predictor of Internal Carotid Artery Aneurysm Recurrence After Coiling. Neurosurgery 2018; 84:607-615. [DOI: 10.1093/neuros/nyy073] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 02/16/2018] [Indexed: 11/14/2022] Open
Affiliation(s)
- Iku Nambu
- Department of Neurosurgery, Kanazawa University School of Medicine, Ishikawa, Japan
| | - Kouichi Misaki
- Department of Neurosurgery, Kanazawa University School of Medicine, Ishikawa, Japan
| | - Naoyuki Uchiyama
- Department of Neurosurgery, Kanazawa University School of Medicine, Ishikawa, Japan
| | - Masanao Mohri
- Department of Neurosurgery, Kanazawa University School of Medicine, Ishikawa, Japan
| | - Takashi Suzuki
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
| | - Hiroyuki Takao
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
| | - Kazuya Futami
- Department of Neurosurgery, Mattoh-Ishikawa Central Hospital, Ishikawa, Japan
| | - Tomoki Kawamura
- Japan Advanced Institute of Science and Technology, Ishikawa, Japan
| | - Yasushi Inoguchi
- Japan Advanced Institute of Science and Technology, Ishikawa, Japan
| | - Teruo Matsuzawa
- Japan Advanced Institute of Science and Technology, Ishikawa, Japan
| | - Mitsutoshi Nakada
- Department of Neurosurgery, Kanazawa University School of Medicine, Ishikawa, Japan
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Longo M, Granata F, Racchiusa S, Mormina E, Grasso G, Longo GM, Garufi G, Salpietro FM, Alafaci C. Role of Hemodynamic Forces in Unruptured Intracranial Aneurysms: An Overview of a Complex Scenario. World Neurosurg 2017; 105:632-642. [DOI: 10.1016/j.wneu.2017.06.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/04/2017] [Accepted: 06/05/2017] [Indexed: 12/16/2022]
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