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Tobe Y, Yagi T, Kawamura K, Suto K, Sawada Y, Hayashi Y, Yoshida H, Nishitani K, Okada Y, Kitahara S, Umezu M. Three-dimensional wall-thickness distributions of unruptured intracranial aneurysms characterized by micro-computed tomography. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01835-5. [PMID: 38489080 DOI: 10.1007/s10237-024-01835-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/21/2024] [Indexed: 03/17/2024]
Abstract
Aneurysmal rupture is associated with wall thinning, but the mechanism is poorly understood. This study aimed to characterize the three-dimensional wall-thickness distributions of unruptured intracranial aneurysms. Five aneurysmal tissues were investigated using micro-computed tomography. First, the wall thickness was related to the aneurysmal wall appearances during surgery. The median wall thicknesses of the translucent and non-translucent walls were 50.56 and 155.93 µm, respectively (p < 0.05) with significant variation in the non-translucent wall thicknesses (p < 0.05). The three-dimensional observations characterized the spatial variation of wall thicknesses. Thin walls showed a uniform thickness profile ranging from 10 to 40 µm, whereas thick walls presented a peaked thickness profile ranging from 300 to 500 µm. In transition walls, the profile undulated due to the formation of focal thin/thick spots. Overall, the aneurysmal wall thicknesses were strongly site-dependent and spatially varied by 10 to 40 times within individual cases. Aneurysmal walls are exposed to wall stress driven by blood pressure. In theory, the magnitude of wall stress is inversely proportional to wall thickness. Thus, the observed spatial variation of wall thickness may increase the spatial variation of wall stress to a similar extent. The irregular wall thickness may yield stress concentration. The observed thin walls and focal thin spots may be caused by excessive wall stresses at the range of mechanical failure inducing wall injuries, such as microscopic tears, during aneurysmal enlargement. The present results suggested that blood pressure (wall stress) may have a potential of acting as a trigger of aneurysmal wall injury.
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Affiliation(s)
- Yasutaka Tobe
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan
| | - Takanobu Yagi
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan.
| | - Koichi Kawamura
- Second Department of Pathology, Akita University, Akita, Japan
| | - Kenta Suto
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan
| | - Yoichi Sawada
- Department of Health and Welfare Science, Okayama Prefectural University, Okayama, Japan
| | - Yoshifumi Hayashi
- Department of Neurosurgery, Kitahara International Hospital, Tokyo, Japan
| | - Hirotaka Yoshida
- Department of Neurosurgery, Tokyo General Hospital, Tokyo, Japan
| | | | - Yoshifumi Okada
- Department of Neurosurgery, Kitahara International Hospital, Tokyo, Japan
| | - Shigemi Kitahara
- Department of Neurosurgery, Kitahara International Hospital, Tokyo, Japan
| | - Mitsuo Umezu
- Center for Advanced Biomedical Sciences, Waseda University, 2-2 Wakamatsucho Shinjukuku, Tokyo, 162-8480, Japan
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Zhang W, Huang G, Zhang J, Bai Z, Yang K. "Cutoff Clipping" Technique as a Tentative Clipping Alternative for Large Aneurysms: A Preliminary Study. J Craniofac Surg 2023; 34:e651-e654. [PMID: 37394697 PMCID: PMC10521781 DOI: 10.1097/scs.0000000000009510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023] Open
Abstract
BACKGROUND Intraoperative rupture of an aneurysm is potentially devastating. The thin-walled regions (TIWRs) of an aneurysm are associated with rupture risk. This study aimed to describe the feasibility and concerns of the "cutoff clipping" technique for TIWRs disposition of certain complex aneurysms. METHODS Three cases were reported to illustrate the "cutoff clipping" technique which was applied to clip a large aneurysm. This study emphasized the exposure and clipping of the aneurysm fundus. The fundus was dissected according to the TIWRs size threshold the author proposed and was clipped transversely by a temporary clip to achieve size reduction and blood flow disconnection. The authors called this the "cutoff clipping" technique. After the cutoff clip was placed, the neck of the aneurysm was further dissected and clipped. RESULTS After successfully placing the cutoff clip, the surgeon achieved to reduce the size of the fundus, decrease the TIWRs proportion, and disconnect the blood flow from the neck to the distal thin-walled dome. Sequentially, three aneurysms were clip-ligated without complications. CONCLUSION The "cutoff clipping" technique applied under suitable conditions is a potential choice to dissect and clip a complex aneurysm with an adhesive neck and thin-walled dome.
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Affiliation(s)
- Weihua Zhang
- Center for Rehabilitation Medicine, Department of Neurosurgery, Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College, Hangzhou, China
| | - Gaoming Huang
- Department of Neurosurgery, The First People’s Hospital of Aksu Region, Aksu, Xinjiang, China
| | - Jian Zhang
- Department of Neurosurgery, The First People’s Hospital of Aksu Region, Aksu, Xinjiang, China
| | - Zennan Bai
- Department of Neurosurgery, The First People’s Hospital of Aksu Region, Aksu, Xinjiang, China
| | - Kaichuang Yang
- Center for Rehabilitation Medicine, Department of Neurosurgery, Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College, Hangzhou, China
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Wei H, Yao K, Tian Q, Han S, Gao W, Han W, Liu S, Wang G, Chen Q, Li M. Low Wall Shear Stress and High Intra-aneurysmal Pressure are Associated with Ruptured Status of Vertebral Artery Dissecting Aneurysms. Cardiovasc Intervent Radiol 2023; 46:240-248. [PMID: 36653659 DOI: 10.1007/s00270-022-03353-2] [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] [Received: 04/18/2022] [Accepted: 12/26/2022] [Indexed: 01/20/2023]
Abstract
PURPOSE The morphological and hemodynamic features of patients with vertebral artery dissecting aneurysms (VADAs) are yet unknown. This study sought to elucidate morphological and hemodynamic features of patients with ruptured and unruptured VADAs based on computed flow simulation. METHODS Fifty-two patients (31 unruptured and 21 ruptured VADAs) were admitted to two hospitals between March 2016 and October 2021. All VADAs were located in the intradural segment, and their clinical, morphological, and hemodynamic parameters were retrospectively analyzed. The hemodynamic parameters were determined through computational fluid dynamics simulations. Univariate statistical and multivariable logistic regression analyses were employed to select significantly different parameters and identify key factors. Receiver operating characteristic (ROC) analysis was used to assess the discrimination for each key factor. RESULTS Four hemodynamic parameters were observed to significantly differ between ruptured and unruptured VADAs, including wall shear stress (WSS), low shear area, intra-aneurysmal pressure (IAP), and relative residence time. However, no significant differences were observed in morphological parameters between ruptured and unruptured VADAs. Multivariable logistic regression analysis revealed that low WSS and high IAP were significantly observed in the ruptured VADAs and demonstrated adequate discrimination. CONCLUSIONS This research indicates significant hemodynamic differences, but no morphological differences were observed between ruptured and unruptured VADAs. The ruptured group had significantly lower WSS and higher IAP than the unruptured group. To further confirm the roles of low WSS and high IAP in the rupture of VADAs, large prospective studies and long-term follow-up of unruptured VADAs are required.
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Affiliation(s)
- Heng Wei
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Kun Yao
- Department of Neurosurgery, Jingzhou Central Hospital, Jingzhou, 434020, China
| | - Qi Tian
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Shoumeng Han
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Wenhong Gao
- Department of Neurosurgery, Jingzhou Central Hospital, Jingzhou, 434020, China
| | - Wenrui Han
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Sheng Liu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Guijun Wang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Qianxue Chen
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China
| | - Mingchang Li
- Department of Neurosurgery, Renmin Hospital of Wuhan University, 99 Ziyang Road, Wuhan, 430060, Hubei Province, China.
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Reproducibility of the computational fluid dynamic analysis of a cerebral aneurysm monitored over a decade. Sci Rep 2023; 13:219. [PMID: 36604495 PMCID: PMC9816094 DOI: 10.1038/s41598-022-27354-w] [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: 08/17/2022] [Accepted: 12/30/2022] [Indexed: 01/06/2023] Open
Abstract
Computational fluid dynamics (CFD) simulations are increasingly utilised to evaluate intracranial aneurysm (IA) haemodynamics to aid in the prediction of morphological changes and rupture risk. However, these models vary and differences in published results warrant the investigation of IA-CFD reproducibility. This study aims to explore sources of intra-team variability and determine its impact on the aneurysm morphology and CFD parameters. A team of four operators were given six sets of magnetic resonance angiography data spanning a decade from one patient with a middle cerebral aneurysm. All operators were given the same protocol and software for model reconstruction and numerical analysis. The morphology and haemodynamics of the operator models were then compared. The segmentation, smoothing factor, inlet and outflow branch lengths were found to cause intra-team variability. There was 80% reproducibility in the time-averaged wall shear stress distribution among operators with the major difference attributed to the level of smoothing. Based on these findings, it was concluded that the clinical applicability of CFD simulations may be feasible if a standardised segmentation protocol is developed. Moreover, when analysing the aneurysm shape change over a decade, it was noted that the co-existence of positive and negative values of the wall shear stress divergence (WSSD) contributed to the growth of a daughter sac.
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Diab R, Chang D, Zhu C, Levitt MR, Aksakal M, Zhao HL, Huynh TJ, Romero-Sanchez G, Mossa-Basha M. Advanced cross-sectional imaging of cerebral aneurysms. Br J Radiol 2023; 96:20220686. [PMID: 36400095 PMCID: PMC10997029 DOI: 10.1259/bjr.20220686] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/05/2022] [Accepted: 11/07/2022] [Indexed: 11/21/2022] Open
Abstract
While the rupture rate of cerebral aneurysms is only 1% per year, ruptured aneurysms are associated with significant morbidity and mortality, while aneurysm treatments have their own associated risk of morbidity and mortality. Conventional markers for aneurysm rupture include patient-specific and aneurysm-specific characteristics, with the development of scoring systems to better assess rupture risk. These scores, however, rely heavily on aneurysm size, and their accuracy in assessing risk in smaller aneurysms is limited. While the individual risk of rupture of small aneurysms is low, due to their sheer number, the largest proportion of ruptured aneurysms are small aneurysms. Conventional imaging techniques are valuable in characterizing aneurysm morphology; however, advanced imaging techniques assessing the presence of inflammatory changes within the aneurysm wall, hemodynamic characteristics of blood flow within aneurysm sacs, and imaging visualization of irregular aneurysm wall motion have been used to further determine aneurysm instability that otherwise cannot be characterized by conventional imaging techniques. The current manuscript reviews conventional imaging techniques and their value and limitations in cerebral aneurysm characterization, and evaluates the applications, value and limitations of advanced aneurysm imaging and post-processing techniques including intracranial vessel wall MRA, 4D-flow, 4D-CTA, and computational fluid dynamic simulations.
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Affiliation(s)
- Rawan Diab
- American University of Beirut School of
Medicine, Beirut, Lebanon
| | - Dandan Chang
- Department of Radiology, University of
Washington, Seattle, United States
| | - Chengcheng Zhu
- Department of Radiology, University of
Washington, Seattle, United States
| | | | - Mehmet Aksakal
- Department of Radiology, University of
Washington, Seattle, United States
| | - Hui-Lin Zhao
- Deparment of Radiology, Renji Hospital,
Shanghai, China
| | - Thien J. Huynh
- Department of Radiology, Mayo
Clinic-Jacksonville, Jacksonville, United States
| | - Griselda Romero-Sanchez
- Department of Radiology, Instituto Nacional de Ciencias
Medicas y Nutricion Salvador Zubiran, Mexico City,
Mexico
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Muhib F, Islam MD, Arafat MT. A study on the computational hemodynamic and mechanical parameters for understanding intracranial aneurysms of patients with hypertension and atrial fibrillation. INFORMATICS IN MEDICINE UNLOCKED 2022. [DOI: 10.1016/j.imu.2022.101031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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7
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Masuda S, Fujimura S, Takao H, Takeshita K, Suzuki T, Uchiyama Y, Karagiozov K, Ishibashi T, Fukudome K, Yamamoto M, Murayama Y. Effects of different stent wire mesh densities on hemodynamics in aneurysms of different sizes. PLoS One 2022; 17:e0269675. [PMID: 35687558 PMCID: PMC9187070 DOI: 10.1371/journal.pone.0269675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 05/25/2022] [Indexed: 11/25/2022] Open
Abstract
Background Intracranial stents are used to treat aneurysms by diverting the blood flow from entering into the aneurysmal dome. Although delayed rupture is rare, clinical outcomes are extremely poor in such cases. Hemodynamics after stent deployment may be related to delayed rupture and a better understanding of the basic characteristics of pressure changes resulting from stent deployment is needed; therefore, this study investigated the relationships between hemodynamics in aneurysms of different sizes treated using stents of different wire mesh densities. Methods Using computational fluid dynamics analysis, parameters related to velocity, volume flow rate, pressure, and residual volume inside the aneurysm were evaluated in digital models of 5 basic aneurysms of differing sizes (Small, Medium, Medium-Large, Large, and Giant) and using 6 different types of stent (varying number of wires, stent pitch and wire mesh density) for each aneurysm. Results Regardless of the aneurysm size, the velocity inside the aneurysm and the volume flow rate into the aneurysm were observed to continuously decrease up to 89.2% and 78.1%, respectively, with increasing stent mesh density. In terms of pressure, for giant aneurysms, the pressure on the aneurysmal surface elevated to 10.3%, then decreased to 5.1% with increasing stent mesh density. However, in smaller aneurysms, this pressure continuously decreased with increasing stent mesh density. The flow-diverting effect of the stents was limited when a stent with low mesh density (under 20%) was used with a giant aneurysm. Conclusions The present results indicate that the selection of appropriate stents according to aneurysm size may contribute to reduced risks of hemodynamic alternations related to stent deployment, which could reduce the incidence of delayed rupture.
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Affiliation(s)
- Shunsuke Masuda
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
- Cybernet Systems Co., Ltd., Tokyo, Japan
| | - Soichiro Fujimura
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Hiroyuki Takao
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
- Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
- * E-mail:
| | - Kohei Takeshita
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Suzuki
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
- Digital Health & SYNGO Department, Siemens Healthcare K.K., Tokyo, Japan
| | - Yuya Uchiyama
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Kostadin Karagiozov
- Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Toshihiro Ishibashi
- Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Koji Fukudome
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
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Tanaka R, Liew BS, Yamada Y, Sasaki K, Miyatani K, Komatsu F, Kawase T, Kato Y, Hirose Y. Depiction of Cerebral Aneurysm Wall by Computational Fluid Dynamics (CFD) and Preoperative Illustration. Asian J Neurosurg 2022; 17:43-49. [PMID: 35873850 PMCID: PMC9298587 DOI: 10.1055/s-0042-1749148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Introduction
Preoperative illustration is a part of an important exercise to study the configuration, direction, and presence of any perforations, and is the weakest point in the wall of the cerebral aneurysm. The same illustration is used to study the surrounding brain structures to decide the best and safe surgical approach prior to any surgical procedure. With the evolution of the aneurysm wall study and study of flow dynamic within the involved artery and its aneurysm wall using computational fluid dynamics (CFD), a better surgical plan can be formulated to improve the flow dynamics. As one of the clinical applications of CFD, we propose a study using a composite image that combines preoperative illustration and CFD, which is traditionally widely used in neurosurgery.
Methods and Materials
We study the use of illustrations of the unruptured cerebral aneurysm of internal carotid-posterior communicating (ICPC) artery and anterior communicating artery (AcomA) treated at our hospital. The combinations of both preoperative illustrations and CFD images by using “ipad Pro” were used.
Result and Conclusion
Medical illustration in the preoperative study of unruptured cerebral aneurysm with combinations of CFD and surrounding brain structures is helpful to decide the surgical approaches and successful surgical treatments.
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Affiliation(s)
- Riki Tanaka
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Boon Seng Liew
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Yasuhiro Yamada
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Kento Sasaki
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Kyosuke Miyatani
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Fuminari Komatsu
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Tsukasa Kawase
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Yoko Kato
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
| | - Yuichi Hirose
- Department of Neurosurgery, Fujita Health University Bantane Hospital, Nagoya, Aichi, Japan
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Yatomi K, Mitome-Mishima Y, Fujii T, Teranishi K, Oishi H, Kondo A. Outcomes following aneurysmal coil embolization with intentionally shortened low-profile visible intraluminal support stent deployment. Neuroradiol J 2022; 35:77-85. [PMID: 34187225 PMCID: PMC8826284 DOI: 10.1177/19714009211026925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Among all stents available for neuroendovascular therapy, the low-profile visible intraluminal support stent bears the highest metal coverage ratio. We deployed a low-profile visible intraluminal support stent with a delivery wire or/and microcatheter system push action to shorten the low-profile visible intraluminal support stent and thus achieve a flow diversion effect. We report our single-institution experience with the use of low-profile visible intraluminal support stents for intentionally shortened deployment (shortening group) and non-shortened deployment (non-shortening group) for unruptured intracranial aneurysms. METHODS We retrospectively reviewed the medical records of 130 patients with 131 intracranial aneurysms who were treated with low-profile visible intraluminal support stent-assisted coil embolization from February 2016-January 2019. All perioperative complications were noted. Every 6 months, we re-examined the patients with cerebral angiography or magnetic resonance angiography. The outcomes of aneurysm occlusion were evaluated by the modified Raymond-Roy occlusion classification. We used the finite element method and computational fluid dynamics to investigate the hemodynamics after shortened low-profile visible intraluminal support stent deployment. RESULTS Immediately after treatment, the modified Raymond-Roy occlusion classification was significantly better in the shortening group than in the non-shortening group (p<0.05). The latest angiographic outcomes showed the same tendency. Hemodynamic analysis by computational fluid dynamics suggested an adequate flow diversion effect with the use of our intentional shortening method. CONCLUSIONS Stent-assisted coil embolization using this technique showed good results of a high complete occlusion rate and low complication rate. These findings suggest that shortened low-profile visible intraluminal support stent deployment yields a flow diversion effect and may lead to early intra-aneurysmal thrombus formation.
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Affiliation(s)
- Kenji Yatomi
- Department of Neurosurgery, Juntendo
University Faculty of Medicine, Japan,Kenji Yatomi, Department of Neurosurgery, Juntendo
University Faculty of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Yumiko Mitome-Mishima
- Department of Neurosurgery, Juntendo
University Faculty of Medicine, Japan,Department of Neurosurgery, National
Defense Medical College, Japan
| | - Takashi Fujii
- Department of Neurosurgery, National
Defense Medical College, Japan,Department of Neuroendovascular Therapy,
Juntendo University Faculty of Medicine, Japan
| | - Kohsuke Teranishi
- Department of Neurosurgery, Juntendo
University Faculty of Medicine, Japan
| | - Hidenori Oishi
- Department of Neurosurgery, Juntendo
University Faculty of Medicine, Japan,Department of Neuroendovascular Therapy,
Juntendo University Faculty of Medicine, Japan
| | - Akihide Kondo
- Department of Neurosurgery, Juntendo
University Faculty of Medicine, Japan
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10
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Letter to Wall Enhancement, Hemodynamics, and Morphology in Unruptured Intracranial Aneurysms with High Rupture Risk. Transl Stroke Res 2022; 13:507-508. [PMID: 35088372 DOI: 10.1007/s12975-021-00982-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 12/19/2021] [Accepted: 12/21/2021] [Indexed: 10/19/2022]
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Fujimura S, Brehm A, Takao H, Uchiyama Y, Karagiozov K, Fukudome K, Yamamoto M, Murayama Y, Psychogios MN. Hemodynamic Characteristics and Clinical Outcome for Intracranial Aneurysms treated with the Derivo Embolization Device, a Novel Second-Generation Flow Diverter. World Neurosurg 2021; 159:e252-e259. [PMID: 34929366 DOI: 10.1016/j.wneu.2021.12.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/10/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND PURPOSE We investigated the relationship between hemodynamic characteristics and clinical outcomes for aneurysms treated by the Derivo Embolization Device (DED), a novel second-generation Flow-Diverter Stent, using computational fluid dynamics (CFD). MATERIALS AND METHODS Data were retrospectively obtained from two centers between 2017 and 2019. During the period, 23 patients were treated for 23 aneurysms with DED. In 17 patients we were able to conduct CFD analysis as six were excluded due to pre-coiling, unsuitable arterial geometry, and complex geometric form. Aneurysm occlusion was rated with the O`Kelly-Marotta (OKM) grading scale on DSA 6 months after stent placement in all patients. Hemodynamic and morphological parameters were statistically compared between two groups: with full occlusion and with a remnant. RESULTS Full occlusion was observed in 17 out of 23 (73.9%) patients. In the group suitable for CFD analysis, we observed 13 fully occluded aneurysms and 4 with any remnant (specifically 1 OKM C, 1 B and 2 A). The energy loss per volume (ELV), which indicates the energy loss through the aneurysm, was significantly larger in pre and post stenting (p<.05) in the complete occlusion cases. In addition, the inflow concentration index (ICI) and inflow area ratio (IAR) of the remnant cases were significantly larger and lower, respectively (p<.05). CONCLUSION Our CFD results indicate that the energy loss involved with the blood flow passing through an aneurysm and concentrated inflow into aneurysm were the most important factors to determine whether an aneurysm will become a complete occlusion or remnant case.
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Affiliation(s)
- Soichiro Fujimura
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Alex Brehm
- Department of Neuroradiology, Clinic for Radiology & Nuclear Medicine, University Hospital Basel, Basel, Switzerland
| | - Hiroyuki Takao
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yuya Uchiyama
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kostadin Karagiozov
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Koji Fukudome
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Marios-Nikos Psychogios
- Department of Neuroradiology, Clinic for Radiology & Nuclear Medicine, University Hospital Basel, Basel, Switzerland.
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12
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Chen S, Bai B, Lv N, Cheng Y, Ji B. Hemodynamic analysis and implantation strategies of delayed intracranial aneurysm rupture after flow diverter treatment. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1735. [PMID: 35071429 PMCID: PMC8743709 DOI: 10.21037/atm-21-5939] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/02/2021] [Indexed: 01/16/2023]
Abstract
BACKGROUND Delayed aneurysm rupture after flow diverters (FDs) is a serious complication which mechanism remains unclear. The hemodynamics of FDs with proximal or distal densification implantation strategies have rarely been reported. In this study, we investigated not only the hemodynamic factors involved in postoperative rupture, but also the hemodynamic effects of different FDs implantation strategies on avoiding this complication. METHODS We selected 2 internal carotid artery (ICA) aneurysms with similar morphological characteristics, both of which were treated with FDs but had opposite therapeutic outcomes (Case 1, ruptured after FD treatment; Case 2, recovered). The FDs strategies we designed were strategy A [with homogeneous 30% metal coverage ratio (MCR)], strategy B (with distal densification of 40% and proximal 30% MCR) and strategy C (with proximal densification of 40% and distal 30% MCR). Virtually FDs deployment and computational fluid dynamics (CFD) method were performed to simulate FDs implantation strategies and analyze the hemodynamics associated with postoperative rupture. RESULTS After FDs implantation, the velocity of blood entering the aneurysm decreased (Case 1, 25.4%; Case 2, 30.6%), but the inflow jet impingement still existed in Case 1. The overall WSS decreased similarly in both cases, but the high WSS region hardly diminished in Case 1. For overall wall pressure, Case 2 decreased slightly but increased in Case 1. Of the three FDs implantation strategies, strategy C had the best hemodynamic effects, including the maximum blood velocity reduction and a tendency to form a more stable flow pattern, the maximum reduction rate of overall WSS and the effective diminish of high WSS area as well as the overall decrease of wall pressure. CONCLUSIONS Not significant decrease of blood flow velocity entering the aneurysm adding persistent impact of inflow jet impingement, high WSS area that did not diminish and abnormal increase of pressure on the aneurysm wall may be causative of postoperative rupture and bleeding of ICA aneurysms. In addition, the hemodynamic effects were favorable when the FD was improved to proximal densification, which may reduce the risk of delayed aneurysm rupture following FDs treatment. KEYWORDS Delayed rupture; flow diverter (FD); computational fluid dynamics (CFD); intracranial aneurysm (IAs); internal carotid artery (ICA).
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Affiliation(s)
- Shiyao Chen
- Shanghai Interventional Medical Device Engineering Technology Research Center, University of Shanghai for Science and Technology, Shanghai, China
| | - Bin Bai
- Shanghai Interventional Medical Device Engineering Technology Research Center, University of Shanghai for Science and Technology, Shanghai, China
| | - Nan Lv
- Department of Neurosurgery, First Affiliated Hospital of Naval Military Medical University, Changhai Hospital of Shanghai, Shanghai, China
| | - Yunzhang Cheng
- Shanghai Interventional Medical Device Engineering Technology Research Center, University of Shanghai for Science and Technology, Shanghai, China
| | - Bin Ji
- Department of Radiology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China
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14
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Ishii T, Fujimura S, Takao H, Uchiyama Y, Okudaira T, Ishibashi T, Otani K, Karagiozov K, Fukudome K, Yamamoto M, Murayama Y. Hemodynamic and Morphological Factors Related to Coil Compaction in Basilar Artery Tip Aneurysms. World Neurosurg 2021; 155:e95-e110. [PMID: 34389523 DOI: 10.1016/j.wneu.2021.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE Coil compaction is directly related to the degree of cerebral aneurysmal recanalization. The Degree of Recanalization (DoR) was quantified by measuring the volume vacated by coil deformation. The purpose of this study was to clarify the hemodynamic and morphological factors associated with coil compaction. METHODS Computational fluid dynamics (CFD) simulations were performed on 28 middle size (5-10 mm), unruptured basilar artery tip aneurysms. The DoR was measured by comparing the coil mass shape obtained from three-dimensional digital subtraction angiography data immediately after coil embolization and again within 1 to 2 years of follow-up. Deployed coils were modeled using a virtual coiling technique for CFD simulations. Hemodynamic and morphological factors to predict the DoR were derived using multiple linear regression. RESULTS Aneurysmal neck area, the maximum pressure generated on the neck surface after coil embolization, and the high-pressure position on the neck surface predicted DoR with statistical significance (p<0.001, p<0.001, p=0.004, respectively). DoR tended to increase when the neck area was large, the pressure generated on the coils was high, and the high-pressure position was close to the center of the neck surface. The volume embolization ratio was not statistically relevant for the DoR in the cases of this study. CONCLUSIONS Coil compaction occurs in cerebral aneurysms with a wide neck, high pressure generated on the coils, and high pressure in the center of the neck surface. Establishing the DoR can contribute to the prediction of recanalization after coil embolization.
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Affiliation(s)
- Takumi Ishii
- Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Soichiro Fujimura
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroyuki Takao
- Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Yuya Uchiyama
- Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Takuma Okudaira
- Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan; Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Toshihiro Ishibashi
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Katharina Otani
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan; Siemens Healthcare K.K. 1-11-1 Osaki, Shinagawa-ku, Tokyo 141-8644, Japan
| | - Kostadin Karagiozov
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Koji Fukudome
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan.
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Kimura H, Osaki S, Hayashi K, Taniguchi M, Fujita Y, Seta T, Tomiyama A, Sasayama T, Kohmura E. Newly Identified Hemodynamic Parameter to Predict Thin-Walled Regions of Unruptured Cerebral Aneurysms Using Computational Fluid Dynamics Analysis. World Neurosurg 2021; 152:e377-e386. [PMID: 34087458 DOI: 10.1016/j.wneu.2021.05.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/23/2021] [Accepted: 05/24/2021] [Indexed: 12/01/2022]
Abstract
BACKGROUND The thin-walled regions (TIWRs) of intracranial aneurysms have a high risk of rupture during surgical manipulation. They have been reported to be predicted by wall shear stress and pressure (PS) based on computational fluid dynamics analysis, although this remains controversial. In this study, we investigated whether the oscillatory shear index (OSI) can predict TIWRs. METHODS Twenty-five unruptured aneurysms were retrospectively analyzed; the position and orientation of the computational fluid dynamics color maps were adjusted to match the intraoperative micrographs. The red area on the aneurysm wall was defined as TIWR, and if most of the regions on the color map corresponding to TIWR were OSI low (lower quartile range), time-averaged wall shear stress (TAWSS) high, or PS high (upper quartile range), each region was defined as a matched region and divided by the total number of TIWRs to calculate the match rate. In addition, the mean values of OSI, TAWSS, and PS corresponding to TIWRs were quantitatively compared with those in adjacent thick-walled regions. RESULTS Among 27 TIWRs of 25 aneurysms, 23, 10, and 14 regions had low OSI, high TAWSS, and high PS regions (match rate: 85.2%, 37.0%, and 51.9%), respectively. Receiver operating characteristic curve analysis demonstrated that OSI was the most effective hemodynamic parameter (area under the curve, 0.881), followed by TAWSS (0.798). Multivariate analysis showed that OSI was a significant independent predictor of TIWRs (odds ratio, 18.30 [95% CI, 3.2800-102.00], P < 0.001). CONCLUSIONS OSI may be a unique predictor for TIWRs. Low OSI strongly corresponds with TIWRs of intracranial aneurysms.
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Affiliation(s)
- Hidehito Kimura
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Susumu Osaki
- Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Kosuke Hayashi
- Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Masaaki Taniguchi
- Department of Neurosurgery, Osaka Neurological Institute, Toyonaka, Japan
| | - Yuichi Fujita
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Seta
- Graduate School of Science and Engineering for Research, University of Toyama, Toyama, Japan
| | - Akio Tomiyama
- Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Takashi Sasayama
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eiji Kohmura
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Neurosurgery, Kinki Central Hospital, Itami, Japan
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The association between hemodynamics and wall characteristics in human intracranial aneurysms: a review. Neurosurg Rev 2021; 45:49-61. [PMID: 33913050 DOI: 10.1007/s10143-021-01554-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/02/2021] [Accepted: 04/20/2021] [Indexed: 12/28/2022]
Abstract
Hemodynamics plays a key role in the natural history of intracranial aneurysms (IAs). However, studies exploring the association between aneurysmal hemodynamics and the biological and mechanical characteristics of the IA wall in humans are sparse. In this review, we survey the current body of literature, summarize the studies' methodologies and findings, and assess the degree of consensus among them. We used PubMed to perform a systematic review of studies that explored the association between hemodynamics and human IA wall features using different sources. We identified 28 publications characterizing aneurysmal flow and the IA wall: 4 using resected tissues, 17 using intraoperative images, and 7 using vessel wall magnetic resonance imaging (MRI). Based on correlation to IA tissue, higher flow conditions, such as high wall shear stress (WSS) with complex pattern and elevated pressure, were associated with degenerated walls and collagens with unphysiological orientation and faster synthesis. MRI studies strongly supported that low flow, characterized by low WSS and high blood residence time, was associated with thicker walls and post-contrast enhancement. While significant discrepancies were found among those utilized intraoperative images, they generally supported that thicker walls coexist at regions with prolonged residence time and that thinner regions are mainly exposed to higher pressure with complex WSS patterns. The current body of literature supports a theory of two general hemodynamic-biologic mechanisms for IA development. One, where low flow conditions are associated with thickening and atherosclerotic-like remodeling, and the other where high and impinging flow conditions are related to wall degeneration, thinning, and collagen remodeling.
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17
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Uchikawa H, Kin T, Takeda Y, Koike T, Kiyofuji S, Koizumi S, Shiode T, Suzuki Y, Miyawaki S, Nakatomi H, Mukasa A, Saito N. Correlation of Inflow Velocity Ratio Detected by Phase Contrast Magnetic Resonance Angiography with the Bleb Color of Unruptured Intracranial Aneurysms. World Neurosurg X 2021; 10:100098. [PMID: 33733086 PMCID: PMC7941010 DOI: 10.1016/j.wnsx.2021.100098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/05/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Intraoperative rupture is the most fatal and catastrophic complication of surgery for unruptured intracranial aneurysms (UIAs); thus, it is extremely useful to predict reddish and thin-walled regions of the UIA before surgery. Although several studies have reported a relationship between the hemodynamic characteristics and intracranial aneurysm wall thickness, a consistent opinion is lacking. We aimed to investigate the relationship between objectively and quantitatively evaluated bleb wall color and hemodynamic characteristics using phase-contrast magnetic resonance angiography (PC-MRA). METHODS Ten patients diagnosed with UIA who underwent surgical clipping and preoperative magnetic resonance imaging along with PC-MRA were included in this study. Bleb wall color was evaluated from an intraoperative video. Based on the Red (R), Green, and Blue values, bleb wall redness (modified R value; mR) was calculated and compared with the hemodynamic characteristics obtained from PC-MRA. RESULTS The wall redness distribution of 18 blebs in 11 UIAs in 10 patients was analyzed. Bleb/neck inflow velocity ratio (Vb/Va: r = 0.66, P = 0.003) strongly correlated with mR, whereas bleb/neck inflow rate ratio (r = 0.58, P = 0.012) correlated moderately. Multivariate regression analysis revealed that only Vb/Va (P = 0.017) significantly correlated with mR. There was no correlation between wall shear stress and mR. CONCLUSIONS The bleb redness of UIAs and Vb/Va, calculated using PC-MRA, showed a significantly greater correlation. Thus, it is possible to predict bleb thickness noninvasively before surgery. This will facilitate more detailed pre- and intraoperative strategies for clipping and coiling for safe surgery.
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Key Words
- 3D, 3-dimensional
- Bleb
- CFD, Computational fluid dynamics
- Inflow velocity ratio
- MRI, Magnetic resonance imaging
- PC-MRA, Phase-contrast magnetic resonance angiography
- Phase contrast magnetic resonance angiography
- Qa, Inflow rate of the aneurysm
- Qb, Inflow rate of the bleb
- Qb/Qa, Bleb/neck inflow rate ratio
- RGB, Baseline red, green, and blue
- RRT, Relative residence time
- TIWRs, Thin-walled regions
- TOF, Time-of-flight
- UIAs, Unruptured intracranial aneurysms
- Unruptured intracranial aneurysm
- Va, Inflow velocity of the aneurysm
- Vb, Inflow velocity of the bled
- Vb/Va, Bleb/neck inflow velocity ratio
- WSS, Wall shear stress
- Wall thickness
- mR, Modified R value
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Affiliation(s)
- Hiroki Uchikawa
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
- Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Taichi Kin
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
| | - Yasuhiro Takeda
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
| | - Tsukasa Koike
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
| | | | - Satoshi Koizumi
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
| | - Taketo Shiode
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
| | - Yuichi Suzuki
- Department of Radiology, University of Tokyo, Tokyo, Japan
| | - Satoru Miyawaki
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
| | | | - Akitake Mukasa
- Department of Neurosurgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Nobuhito Saito
- Department of Neurosurgery, University of Tokyo, Tokyo, Japan
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Suzuki T, Hasegawa H, Ando K, Shibuya K, Takahashi H, Saito S, On J, Oishi M, Fujii Y. Hemodynamic features of an intracranial aneurysm rupture predicted by perianeurysmal edema: A case report. Surg Neurol Int 2021; 12:49. [PMID: 33654552 PMCID: PMC7911146 DOI: 10.25259/sni_780_2020] [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: 11/01/2020] [Accepted: 01/15/2021] [Indexed: 12/03/2022] Open
Abstract
Background: Perianeurysmal edema (PAE) has been suggested as an indicator of potential aneurysm rupture; however, the hemodynamic features of these aneurysms are still unknown. A computational fluid dynamic (CFD) analysis was performed to evaluate the hemodynamic features of a very rare case of a ruptured middle cerebral artery (MCA) aneurysm with PAE. Case Description: A 65-year-old woman presented with disturbed consciousness. A subarachnoid hemorrhage due to an azygos anterior cerebral artery (ACA) aneurysm rupture was suspected. An unruptured MCA aneurysm with PAE was identified in the left temporal lobe. Although the ACA aneurysm was clipped to prevent re-bleeding, the MCA aneurysm subsequently ruptured 6 days later. Clipping of the MCA aneurysm was performed, and hemosiderin deposits suggestive of sentinel bleeding were found on the surface of the aneurysm dome. CFD analysis revealed unstable hemodynamic stress at the expanded bleb area after rupture, localized to the rupture site. Moreover, this analysis revealed flow impingement with pressure elevation and low wall shear stress, which indicated increased inflammation and aneurysm wall thinning that likely led to rupture. Conclusion: Hemosiderin deposits at the aneurysm wall and PAE indicates leakage from a cerebral aneurysm. Hemodynamic stress at the aneurysm may promote an inflammatory response and lead to wall weakening accompanied by PAE. Based on our findings, we recommend that surgical intervention should be considered as the first line of treatment for such aneurysms to prevent rupture.
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Affiliation(s)
- Tomoaki Suzuki
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Hitoshi Hasegawa
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Kazuhiro Ando
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Kohei Shibuya
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Haruhiko Takahashi
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Shoji Saito
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Jotaro On
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Makoto Oishi
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
| | - Yukihiko Fujii
- Department of Neurosurgery, Niigata University, Brain Research Institute, Niigata, Japan
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Suzuki T, Hasegawa H, Ando K, Shibuya K, Takahashi H, Saito S, Oishi M, Fujii Y. Possibility of Worsening Flow Diversion Effect Due to Morphological Changes of a Stented Artery With Multiple Overlapping Stents for Partially Thrombosed Vertebral Artery Aneurysms. Front Neurol 2021; 11:611124. [PMID: 33384657 PMCID: PMC7770215 DOI: 10.3389/fneur.2020.611124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Morphological changes of a stented artery can cause a flow diversion effect to reduce intra-aneurysmal flow; however, there is a potential for the negative effect of increased intra-aneurysmal flow. We present cases with multiple overlapping stents for a partially thrombosed vertebral artery aneurysm and characterize the hemodynamic properties of a recurrent case by focusing on the morphological changes of the stented artery. Methods: Between October 2017 and April 2019, four consecutive cases of symptomatic unruptured large and giant partially thrombosed vertebral artery aneurysms were treated with multiple overlapping low-profile visualized intraluminal support stents and no coils. Both angiographic and clinical outcomes were assessed. Computational fluid dynamics analysis was performed to clarify hemodynamic features. The degree of pressure elevation was calculated as the pressure difference (Pd). Wall shear stress (WSS) was also calculated. Results: In three of the four cases, successful flow reduction was achieved with no morphological change of the stented arteries. The patients' symptoms were gradually improved. The remaining case required additional stents after the initial treatment. In the recurrent case, Pd was noticeably elevated at the aneurysm neck after treatment, and WSS was generally increased in the area due to altered blood flow into the aneurysm dome caused by morphological changes of the stented artery. Conclusion: Overlapping stents can be used for the treatment of large and giant thrombosed vertebral artery aneurysms with flow diversion effect; however, morphological changes of the stented artery requires careful attention as it may lead to an increase in the intra-aneurysmal flow, causing negative outcomes.
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Affiliation(s)
- Tomoaki Suzuki
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hitoshi Hasegawa
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kazuhiro Ando
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kouhei Shibuya
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Haruhiko Takahashi
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Shoji Saito
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Makoto Oishi
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Yukihiko Fujii
- Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
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Suzuki T, Genkai N, Nomura T, Abe H. Assessing the Hemodynamics in Residual Cavities of Intracranial Aneurysm after Coil Embolization with Combined Computational Flow Dynamics and Silent Magnetic Resonance Angiography. J Stroke Cerebrovasc Dis 2020; 29:105290. [PMID: 32992205 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105290] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Metal artifacts limit computational fluid dynamics analysis after coil embolization. Silent magnetic resonance angiography reduces metal artifacts and improves visualization of the residual cavity of coil-embolized aneurysms. This study investigated the flow dynamics of the residual cavity after coil embolization using silent magnetic resonance angiography and computational fluid dynamics to elucidate the hemodynamic characteristics of recanalization. METHODS Twenty internal carotid-posterior communicating aneurysm cases treated with coil embolization and without stent assistance were followed up (mean±standard deviation, 13.0±6.1 months) and assessed using silent magnetic resonance angiography. The hemodynamic characteristics of the residual cavities in both types of aneurysms were compared between neck remnants, which persisted for >12 months (NR group), and those treated with coil compaction-induced body filling (BF group). Computational fluid dynamics analysis of each aneurysm was performed using morphological data obtained from silent magnetic resonance angiography. Pressure, pressure difference, normalized wall shear stress, and flow velocity were measured. RESULTS The residual cavity was well-visualized using silent magnetic resonance angiography and compared with those imaged using conventional time-of-flight magnetic resonance angiography, and eight internal carotid-posterior communicating aneurysms with neck remnants and body filling were investigated. The maximum pressure area was localized to the aneurysm wall in the NR group (n=4) and to sides of the coil surface in the BF group (n=4). No significant differences were observed for each hemodynamic parameter. CONCLUSIONS Combination of silent magnetic resonance angiography and computational fluid dynamics helps to understand the hemodynamic characteristics of residual cavity in coil- embolized aneurysms. The flow-impingement zone at the coil surface (maximum pressure area) may influence the risk for future coil compaction.
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Affiliation(s)
- Tomoaki Suzuki
- Department of Neurosurgery, Tachikawa General Hospital, 1-24 Asahioka, Nagaoka 940-8621, Japan; Department of Neurosurgery, Brain Research Institute, Niigata University, 1-757 Asahimachi-Dori, Niigata 951-8585, Japan.
| | - Nobuyuki Genkai
- Department of Neurosurgery, Tachikawa General Hospital, 1-24 Asahioka, Nagaoka 940-8621, Japan
| | - Toshiharu Nomura
- Department of Neurosurgery, Tachikawa General Hospital, 1-24 Asahioka, Nagaoka 940-8621, Japan
| | - Hiroshi Abe
- Department of Neurosurgery, Tachikawa General Hospital, 1-24 Asahioka, Nagaoka 940-8621, Japan
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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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Murayama Y, Fujimura S, Suzuki T, Takao H. Computational fluid dynamics as a risk assessment tool for aneurysm rupture. Neurosurg Focus 2020; 47:E12. [PMID: 31261116 DOI: 10.3171/2019.4.focus19189] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/23/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The authors reviewed the clinical role of computational fluid dynamics (CFD) in assessing the risk of intracranial aneurysm rupture. METHODS A literature review was performed to identify reports on CFD assessment of aneurysms using PubMed. The usefulness of various hemodynamic parameters, such as wall shear stress (WSS) and the Oscillatory Shear Index (OSI), and their role in aneurysm rupture risk analysis, were analyzed. RESULTS The authors identified a total of 258 published articles evaluating rupture risk, growth, and endovascular device assessment. Of these 258 articles, 113 matching for CFD and hemodynamic parameters that contribute to the risk of rupture (such as WSS and OSI) were identified. However, due to a lack of standardized methodology, controversy remains on each parameter's role. CONCLUSIONS Although controversy continues to exist on which risk factors contribute to predict aneurysm rupture, CFD can provide additional parameters to assess this rupture risk. This technology can contribute to clinical decision-making or evaluation of efficacy for endovascular methods and devices.
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Affiliation(s)
- Yuichi Murayama
- Departments of1Neurosurgery and.,2Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo
| | - Soichiro Fujimura
- 2Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo.,3Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo; and
| | - Tomoaki Suzuki
- 4Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hiroyuki Takao
- Departments of1Neurosurgery and.,2Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo.,3Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo; and
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23
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Wu TC, Chen TY, Ko CC, Chen JH, Lin CP. Correlation of internal carotid artery diameter and carotid flow with asymmetry of the circle of Willis. BMC Neurol 2020; 20:251. [PMID: 32563264 PMCID: PMC7305584 DOI: 10.1186/s12883-020-01831-z] [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: 11/28/2019] [Accepted: 06/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of this study was to clarify the effect of asymmetric COW variants on carotid flow changes, and proposed an easy estimate of the representative carotid flow volume for accurate numerical simulation. Methods A total of 210 healthy adults receiving magnetic resonance angiography and carotid duplex sonography were included. Three anterior cerebral artery asymmetry (AA) groups were defined based on the diameter ratio difference (DRD) of bilateral A1 segments: AA1 group, one-side A1 aplasia; AA2, A1 DRD ≥ 50%; AA3, A1 DRD between 10 and 50%. Similarly, 3 posterior communicating artery (PcomA) asymmetry (PA) groups were defined: PA1 group, one fetal-origin posterior cerebral artery and absent contralateral PcomA; PA2, PcomA DRD ≥ 50%; PA3, PcomA DRD between 10 and 50%. Results With A1 asymmetry, the ICA diameter of the dominant A1 is significantly greater than the contralateral side. Significant differences of bilateral ICA flow were present in the AA1 and AA2 groups (mean flow difference 42.9 and 30.7%, respectively). Significant bilateral ICA diameter and flow differences were only found in the PA1 group. Linear regression analysis of ICA diameter and flow found a moderately positive correlation between ICA diameter and flow in all AA groups, with a 1 mm increment in vessel diameter corresponding to a 62.6 ml increment of flow volume. The product of bilateral ICA diameter and flow volume difference (ICA-PDF) could be a potential discriminator with a cutoff of 4.31 to predict A1 asymmetry ≥50% with a sensitivity of 0.81 and specificity of 0.76. Conclusions The study verifies that A1 asymmetry causes unequal bilateral carotid inflow, and consequently different bilateral ICA diameters. Adjustment of the inflow boundary conditions according to the COW variants would be necessary to improve the accuracy of numerical simulation.
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Affiliation(s)
- Te-Chang Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan. .,Department of Medical Sciences Industry, Chang Jung Christian University, Tainan, Taiwan. .,Department of Medical Imaging, Chi-Mei Medical Center, Tainan City, Taiwan.
| | - Tai-Yuan Chen
- Department of Medical Imaging, Chi-Mei Medical Center, Tainan City, Taiwan.,Graduate Institute of Medical Sciences, Chang Jung Christian University, Tainan, Taiwan
| | - Ching-Chung Ko
- Department of Medical Imaging, Chi-Mei Medical Center, Tainan City, Taiwan.,Center of General Education, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Jeon-Hor Chen
- Department of Radiology, E-DA Hospital, E-DA Cancer Hospital, I-Shou University, Kaohsiung, Taiwan.,Center for Functional Onco-Imaging of Radiological Sciences, School of Medicine, University of California, Irvine, California, USA
| | - Ching-Po Lin
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.,Institute of Neuroscience, School of Life Science, National Yang-Ming University, Taipei, Taiwan
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24
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Suzuki T, Stapleton CJ, Koch MJ, Tanaka K, Fujimura S, Suzuki T, Yanagisawa T, Yamamoto M, Fujii Y, Murayama Y, Patel AB. Decreased wall shear stress at high-pressure areas predicts the rupture point in ruptured intracranial aneurysms. J Neurosurg 2020; 132:1116-1122. [DOI: 10.3171/2018.12.jns182897] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/10/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVEDegenerative cerebral aneurysm walls are associated with aneurysm rupture and subarachnoid hemorrhage. Thin-walled regions (TWRs) represent fragile areas that may eventually lead to aneurysm rupture. Previous computational fluid dynamics (CFD) studies reported the correlation of maximum pressure (Pmax) areas and TWRs; however, the correlation with aneurysm rupture has not been established. This study aims to investigate this hemodynamic correlation.METHODSThe aneurysmal wall surface at the Pmax areas was intraoperatively evaluated using a fluid flow formula under pulsatile blood flow conditions in 23 patients with 23 saccular middle cerebral artery (MCA) bifurcation aneurysms (16 unruptured and 7 ruptured). The pressure difference (Pd) at the Pmax areas was calculated by subtracting the average pressure (Pave) from the Pmax and normalized by dividing this by the dynamic pressure at the aneurysm inlet side. The wall shear stress (WSS) was also calculated at the Pmax areas, aneurysm dome, and parent artery. These hemodynamic parameters were used to validate the correlation with TWRs in unruptured MCA aneurysms. The characteristic hemodynamic parameters at the rupture points in ruptured MCA aneurysms were then determined.RESULTSIn 13 of 16 unruptured aneurysms (81.2%), Pmax areas were identified that corresponded to TWRs. In 5 of the 7 ruptured cerebral aneurysms, the Pmax areas coincided with the rupture point. At these areas, the Pd values were not higher than those of the TWRs in unruptured cerebral aneurysms; however, minimum WSS, time-averaged WSS, and normalized WSS at the rupture point were significantly lower than those of the TWRs in unruptured aneurysms (p < 0.01).CONCLUSIONSAt the Pmax area of TWRs, decreased WSS appears to be the crucial hemodynamic parameter that indicates the risk of aneurysm rupture.
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Affiliation(s)
- Tomoaki Suzuki
- 1Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- 2Department of Neurosurgery, Jikei University School of Medicine, Tokyo
- 3Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata
| | - Christopher J. Stapleton
- 1Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Matthew J. Koch
- 1Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Kazutoshi Tanaka
- 4Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo
| | - Soichiro Fujimura
- 4Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo
| | - Takashi Suzuki
- 4Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo
- 5Department of Innovation for Medical Information Technology, Jikei University School of Medicine, Tokyo; and
| | - Takeshi Yanagisawa
- 1Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- 2Department of Neurosurgery, Jikei University School of Medicine, Tokyo
| | - Makoto Yamamoto
- 6Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Yukihiko Fujii
- 3Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata
| | - Yuichi Murayama
- 2Department of Neurosurgery, Jikei University School of Medicine, Tokyo
| | - Aman B. Patel
- 1Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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25
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Kim JH, Han H, Moon YJ, Suh S, Kwon TH, Kim JH, Chong K, Yoon WK. Hemodynamic Features of Microsurgically Identified, Thin-Walled Regions of Unruptured Middle Cerebral Artery Aneurysms Characterized Using Computational Fluid Dynamics. Neurosurgery 2019; 86:851-859. [DOI: 10.1093/neuros/nyz311] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 05/18/2019] [Indexed: 11/14/2022] Open
Abstract
Abstract
BACKGROUND
Thin-walled regions (TWRs) of aneurysm surfaces observed in microscopic surgery are thought to be vulnerable areas for growth and rupture of unruptured intracranial aneurysms (UIAs).
OBJECTIVE
To identify hemodynamic features of TWRs of aneurysms by using computational fluid dynamics (CFD) analyses of unruptured middle cerebral artery bifurcation (MCAB) aneurysms.
METHODS
Nine patients with 11 MCAB aneurysms were enrolled, and their TWRs were identified. CFD analysis was performed using 3 parameters: pressure, wall shear stress (WSS), and WSS divergence (WSSD). Each parameter was evaluated for its correspondence with TWR.
RESULTS
Among 11 aneurysms, 15 TWRs were identified. Corresponding matches with CFD parameters (pressure, WSS, and WSSD) were 73.33, 46.67, and 86.67%, respectively.
CONCLUSION
WSSD, a hemodynamic parameter that accounts for both magnitude and directionality of WSS, showed the highest correspondence. High WSSD might correspond with TWR of intracranial aneurysms, which are likely high-risk areas for rupture.
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Affiliation(s)
- Jang Hun Kim
- Department of Neurosurgery, Armed Forces Capital Hospital, Gyeonggi-do, Republic of Korea
- Department of Neurosurgery, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - Huan Han
- Computational Fluid Dynamics and Acoustics Laboratory, School of Mechanical Engineering, Korea University, Seoul, Republic of Korea
| | - Young-June Moon
- Computational Fluid Dynamics and Acoustics Laboratory, School of Mechanical Engineering, Korea University, Seoul, Republic of Korea
| | - Sangil Suh
- Department of Radiology, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - Taek-Hyun Kwon
- Department of Neurosurgery, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - Jong Hyun Kim
- Department of Neurosurgery, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - Kyuha Chong
- Department of Neurosurgery, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
| | - Won-Ki Yoon
- Department of Neurosurgery, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea
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26
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Hashimoto Y, Matsushige T, Shimonaga K, Hosogai M, Kaneko M, Ono C, Mizoue T. Vessel Wall Imaging Predicts the Presence of Atherosclerotic Lesions in Unruptured Intracranial Aneurysms. World Neurosurg 2019; 132:e775-e782. [PMID: 31415889 DOI: 10.1016/j.wneu.2019.08.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/02/2019] [Accepted: 08/03/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Recent studies have suggested that magnetic resonance vessel wall imaging (VWI) can visualize thickened intracranial aneurysm wall. We aimed to investigate correlations between VWI findings and intraoperative aneurysm wall features based on the hypothesis that VWI can visualize atherosclerotic changes in unruptured intracranial aneurysm (UIA) walls. METHODS A total of 36 microsurgically treated UIAs were retrospectively reviewed. All aneurysms underwent VWI before microsurgical clipping, and fusion images with time-of-flight magnetic resonance angiography were created to localize aneurysm wall enhancement (AWE) lesions. Intraoperatively, 2 neurosurgeons who were blinded to the VWI findings evaluated the aneurysm wall features, giving each aneurysm an atherosclerosis score on a 5-point scale (5: yellowish, 4: whitish, 3: normal, 2: slightly reddish, 1: reddish). We defined atherosclerotic lesions as those having average scores ≥4. We evaluated the rate of correspondence between AWE lesions and atherosclerotic lesions, and the factors associated with AWE. RESULTS Sixteen of the 36 UIAs (44%) were identified as AWE. The sensitivity, specificity, positive predictive value, and negative predictive value of correspondence between AWE lesions and atherosclerotic lesions were 79%, 94%, 94%, and 80%, respectively. The average atherosclerosis scores (4.2 ± 0.5 vs. 2.7 ± 0.9; P < 0.001) were significantly higher in aneurysms with AWE. Twelve of 16 UIAs with wall enhancement had wall thinning adjacent to the part with AWE. CONCLUSIONS AWE lesions corresponded with intraoperatively confirmed atherosclerotic lesions of UIAs. Detecting these lesions would be valuable in exploring UIAs with wall degeneration.
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Affiliation(s)
- Yukishige Hashimoto
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
| | - Toshinori Matsushige
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan.
| | - Koji Shimonaga
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
| | - Masahiro Hosogai
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
| | - Mayumi Kaneko
- Department of Pathology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
| | - Chiaki Ono
- Department of Radiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
| | - Tatsuya Mizoue
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Hiroshima, Japan
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27
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Qiu T, Jin G, Bao W, Lu H. Intercorrelations of morphology with hemodynamics in intracranial aneurysms in computational fluid dynamics. ACTA ACUST UNITED AC 2019; 22:205-212. [PMID: 28678215 PMCID: PMC5946365 DOI: 10.17712/nsj.2017.3.20160452] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Objective: To measure morphological indices and wall shear stress (WSS) of aneurysms and parent artery surface in order to explore the relationship of morphological characteristics and WSS. Methods: Data from 47 events of consecutive cerebral saccular aneurysms from 39 patients which were referred to the interventional Neuroradiology service of the Shaoxing People’s Hospital, Shaoxing, China between 2014 April and 2015 August. Wall shear stress and wall pressure (WP) of the pre-aneurysm, aneurysm and near vessel (<1.0 cm) surface were obtained. Correlation analysis was carried between morphological parameters and WSS and its ratio. WSS, WP, intra-aneurysmal flow pattern, and location of aneurysms were analyzed. Results: Impaction zone from inflow jet was located in the distal neck part of aneurysm with high WSS in 36 aneurysms (76.6%). There were significant differences in WSS between pre-aneurysm surface and near vessel (p<0.001), aneurysm (p<0.001), aneurysm and near vessel (p<0.001). Significant correlations were found between aneurysm WSS and aspect ratio (r=-0.296), aneurysm-artery WSS ratio and size ratio (r=-0.322), aspect ratio (r=-0.416). Conclusion: Uneven WSS distributes in the various part of the pre-aneurysm vessel. The impaction zone from inflow jet is located in the distal neck of aneurysm. Aspect and size ratios can effect aneurysm WSS
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Affiliation(s)
- Tianlun Qiu
- Department of Neurosurgery, Shaoxing People`s Hospital, Shaoxing, Zhejiang, China
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28
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Jiang P, Liu Q, Wu J, Chen X, Li M, Li Z, Yang S, Guo R, Gao B, Cao Y, Wang R, Wang S. Hemodynamic characteristics associated with thinner regions of intracranial aneurysm wall. J Clin Neurosci 2019; 67:185-190. [PMID: 31253387 DOI: 10.1016/j.jocn.2019.06.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 04/20/2019] [Accepted: 06/09/2019] [Indexed: 11/30/2022]
Abstract
Aneurysm wall thickness is an important determinant of aneurysm progression and intra-procedural rupture. Several previous studies have evaluated the association between hemodynamic stress and aneurysm wall thickness, but conflicting results were obtained and no consensus has been achieved. According to the intraoperative findings, twenty-eight unruptured middle cerebral artery (MCA) aneurysms presented with thin-walled regions were enrolled in our study. Patient-specific 3D aneurysm models were constructed from preoperative computed tomography angiography (CTA) data and computational fluid dynamics (CFD) analyses were performed under pulsatile-flow conditions. Thin-walled regions of aneurysm dome were recognized by two experienced reviewers based on the intraoperative microscopy findings. Hemodynamic parameters derived from CFD analysis, including normalized wall shear stress (NWSS), normalized pressure (NP), the oscillatory shear index (OSI) and relative residence time (RRT), were compared between thin-walled regions and surrounding normal-thickness areas. Of the included aneurysms, twenty-eight pairs of thin-walled and normal surrounding regions were determined. Compared with surrounding tissues, thin-walled regions of aneurysm wall tended to present with higher pressure (1.232 vs 1.043, p < 0.05) and lower wall shear stress (0.693 vs 0.868, p < 0.05). Multivariate analysis revealed that elevated NP was significantly associated with thinning of the local aneurysm wall. Higher pressure and lower WSS were characteristic hemodynamic features associated with thinner regions of the aneurysm wall, elevated NP was an independent risk factor for local aneurysm wall thinning. CFD seems to be a useful method to estimate the location of thin-walled region, which will be helpful in reducing the risk of intraoperative rupture.
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Affiliation(s)
- Pengjun Jiang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Qingyuan Liu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Jun Wu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Xin Chen
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Maogui Li
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Zhengsong Li
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Shuzhe Yang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Rui Guo
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Bin Gao
- School of Life Science and BioEngineering, Beijing University of Technology, Beijing, People's Republic of China
| | - Yong Cao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Rong Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China
| | - Shuo Wang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, People's Republic of China; China National Clinical Research Center for Neurological Diseases, Beijing, People's Republic of China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing, People's Republic of China; Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing, People's Republic of China.
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29
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Leemans EL, Cornelissen BMW, Rosalini G, Verbaan D, Schneiders JJ, van den Berg R, Vandertop WP, van Bavel ET, Slump CH, Majoie CBLM, Marquering HA. Impact of Intracranial Aneurysm Morphology and Rupture Status on the Particle Residence Time. J Neuroimaging 2019; 29:487-492. [PMID: 31002750 PMCID: PMC6618041 DOI: 10.1111/jon.12618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/29/2019] [Accepted: 04/02/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Aneurysm hemodynamics play an important role in aneurysm growth and subsequent rupture. Within the available hemodynamic characteristics, particle residence time (PRT) is relatively unexplored. However, some studies have shown that PRT is related to thrombus formation and inflammation. The goal of this study is to evaluate the association between PRT and aneurysm rupture and morphology. METHODS We determined the PRT for 113 aneurysms (61 unruptured, 53 ruptured) based on computational fluid dynamic models. Virtual particles were injected into the parent vessel and followed during multiple cardiac cycles. PRT was defined as the time needed for 99% of the particles that entered an aneurysm to leave the aneurysm. Subsequently, we evaluated the association between PRT, rupture, and morphology (aneurysm type, presence of blebs, or multiple lobulations). RESULTS PRT showed no significant difference between unruptured (1.1 seconds interquartile range [IQR .39-2.0 seconds]) and ruptured aneurysms (1.2 seconds [IQR .47-2.3 seconds]). PRT was influenced by aneurysm morphology. Longer PRTs were seen in bifurcation aneurysms (1.3 seconds [IQR .54-2.4 seconds], P = .01) and aneurysms with blebs or multiple lobulations (1.92 seconds [IQR .94-2.8 seconds], P < .001). Four of five partially thrombosed aneurysms had a long residence time (>1.9 seconds). CONCLUSIONS Our study shows an influence of aneurysm morphology on PRT. Nevertheless, it suggests that PRT cannot be used to differentiate unruptured and ruptured aneurysms.
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Affiliation(s)
- E L Leemans
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - B M W Cornelissen
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,MIRA Institute for Biomedical Engineering and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - G Rosalini
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,Department of Industrial Engineering and Information, University of Pavia, Pavia, Italy
| | - D Verbaan
- Neurosurgical Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - J J Schneiders
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - R van den Berg
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - W P Vandertop
- Neurosurgical Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - E T van Bavel
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - C H Slump
- MIRA Institute for Biomedical Engineering and Technical Medicine, University of Twente, Enschede, the Netherlands
| | - C B L M Majoie
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - H A Marquering
- Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.,Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
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30
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Levitt MR, Mandrycky C, Abel A, Kelly CM, Levy S, Chivukula VK, Zheng Y, Aliseda A, Kim LJ. Genetic correlates of wall shear stress in a patient-specific 3D-printed cerebral aneurysm model. J Neurointerv Surg 2019; 11:999-1003. [PMID: 30979845 DOI: 10.1136/neurintsurg-2018-014669] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 12/29/2022]
Abstract
OBJECTIVES To study the correlation between wall shear stress and endothelial cell expression in a patient-specific, three-dimensional (3D)-printed model of a cerebral aneurysm. MATERIALS AND METHODS A 3D-printed model of a cerebral aneurysm was created from a patient's angiogram. After populating the model with human endothelial cells, it was exposed to media under flow for 24 hours. Endothelial cell morphology was characterized in five regions of the 3D-printed model using confocal microscopy. Endothelial cells were then harvested from distinct regions of the 3D-printed model for mRNA collection and gene analysis via quantitative polymerase chain reaction (qPCR.) Cell morphology and mRNA measurement were correlated with computational fluid dynamics simulations. RESULTS The model was successfully populated with endothelial cells, which survived under flow for 24 hours. Endothelial morphology showed alignment with flow in the proximal and distal parent vessel and aneurysm neck, but disorganization in the aneurysm dome. Genetic analysis of endothelial mRNA expression in the aneurysm dome and distal parent vessel was compared with the proximal parent vessels. ADAMTS-1 and NOS3 were downregulated in the aneurysm dome, while GJA4 was upregulated in the distal parent vessel. Disorganized morphology and decreased ADAMTS-1 and NOS3 expression correlated with areas of substantially lower wall shear stress and wall shear stress gradient in computational fluid dynamics simulations. CONCLUSIONS Creating 3D-printed models of patient-specific cerebral aneurysms populated with human endothelial cells is feasible. Analysis of these cells after exposure to flow demonstrates differences in both cell morphology and genetic expression, which correlate with areas of differential hemodynamic stress.
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Affiliation(s)
- Michael R Levitt
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Radiology, University of Washington, Seattle, WA, USA.,Mechanical Engineering, University of Washington, Seattle, WA, USA.,Stroke and Applied Neuroscience Center, University of Washington, Seattle, WA, USA
| | | | - Ashley Abel
- Neurological Surgery, University of Washington, Seattle, WA, USA
| | - Cory M Kelly
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke and Applied Neuroscience Center, University of Washington, Seattle, WA, USA
| | - Samuel Levy
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Stroke and Applied Neuroscience Center, University of Washington, Seattle, WA, USA
| | | | - Ying Zheng
- Stroke and Applied Neuroscience Center, University of Washington, Seattle, WA, USA.,Bioengineering, University of Washington, Seattle, WA, USA
| | - Alberto Aliseda
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Mechanical Engineering, University of Washington, Seattle, WA, USA.,Stroke and Applied Neuroscience Center, University of Washington, Seattle, WA, USA
| | - Louis J Kim
- Neurological Surgery, University of Washington, Seattle, WA, USA.,Radiology, University of Washington, Seattle, WA, USA.,Stroke and Applied Neuroscience Center, University of Washington, Seattle, WA, USA
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31
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Cebral JR, Detmer F, Chung BJ, Choque-Velasquez J, Rezai B, Lehto H, Tulamo R, Hernesniemi J, Niemela M, Yu A, Williamson R, Aziz K, Shakur S, Amin-Hanjani S, Charbel F, Tobe Y, Robertson A, Frösen J. Local Hemodynamic Conditions Associated with Focal Changes in the Intracranial Aneurysm Wall. AJNR. AMERICAN JOURNAL OF NEURORADIOLOGY 2019; 40:510-516. [PMID: 30733253 DOI: 10.3174/ajnr.a5970] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/25/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively. MATERIALS AND METHODS Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test. RESULTS Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones. CONCLUSIONS Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.
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Affiliation(s)
- J R Cebral
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - F Detmer
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - B J Chung
- From the Department of Bioengineering (J.R.C., F.D., B.J.C.), Volgenau School of Engineering, George Mason University, Fairfax, Virginia
| | - J Choque-Velasquez
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - B Rezai
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - H Lehto
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - R Tulamo
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland.,Department of Vascular Surgery (R.T.), Helsinki University Central Hospital, Helsinki, Finland
| | - J Hernesniemi
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - M Niemela
- Neurosurgery Research Group (J.C.-V., B.R., H.L., R.T., J.H., M.N.), Biomedicum Helsinki and Helsinki University Central Hospital, Helsinki, Finland
| | - A Yu
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - R Williamson
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - K Aziz
- Department of Neurosurgery (A.Y., R.W., K.A.), Allegheny General Hospital, Pittsburgh, Pennsylvania
| | - S Shakur
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - S Amin-Hanjani
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - F Charbel
- Department of Neurosurgery (S.S., S.A.-H., F.C.), University of Illinois at Chicago, Chicago, Illinois
| | - Y Tobe
- Mechanical Engineering and Materials Science and Department of Bioengineering (Y.T., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - A Robertson
- Mechanical Engineering and Materials Science and Department of Bioengineering (Y.T., A.R.), Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - J Frösen
- Hemorrhagic Brain Pathology Research Group (J.F.), Neurocenter, Kuopio University Hospital, Kuopio, Finland
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Shimonaga K, Ishii D, Matsushige T. Response by Shimonaga et al to Letter Regarding Article, "Clinicopathological Insights From Vessel Wall Imaging of Unruptured Intracranial Aneurysms". Stroke 2019; 50:e19. [PMID: 30580747 DOI: 10.1161/strokeaha.118.023850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Koji Shimonaga
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Japan
| | - Daizo Ishii
- Department of Neurosurgery, Graduate School of Biomedical and Health Sciences Hiroshima University, Japan
| | - Toshinori Matsushige
- Department of Neurosurgery and Interventional Neuroradiology, Hiroshima City Asa Citizens Hospital, Japan
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Kimura H, Taniguchi M, Hayashi K, Fujimoto Y, Fujita Y, Sasayama T, Tomiyama A, Kohmura E. Clear Detection of Thin-Walled Regions in Unruptured Cerebral Aneurysms by Using Computational Fluid Dynamics. World Neurosurg 2019; 121:e287-e295. [DOI: 10.1016/j.wneu.2018.09.098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 11/28/2022]
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Cebral JR, Mut F, Gade P, Cheng F, Tobe Y, Frosen J, Robertson AM. Combining data from multiple sources to study mechanisms of aneurysm disease: Tools and techniques. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3133. [PMID: 30055087 PMCID: PMC6231954 DOI: 10.1002/cnm.3133] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/14/2018] [Accepted: 07/15/2018] [Indexed: 05/31/2023]
Abstract
INTRODUCTION Connecting local hemodynamics, biomechanics, and tissue properties in cerebral aneurysms is important for understanding the processes of wall degeneration and subsequent aneurysm progression and rupture. This challenging problem requires integration of data from multiple sources. METHODS This paper describes the tools and techniques developed to integrate data from multiple sources, including clinical information, 3D imaging, intraoperative videos, ex vivo micro-computed tomography (CT), and multiphoton microscopy. Central to this approach is a 3D tissue model constructed from micro-CT images of aneurysm samples resected during neurosurgery. This model is aligned to vascular models constructed from 3D clinical images and is used to map and compare flow, biomechanics, and tissue data. RESULTS The approach is illustrated with data of three human intracranial aneurysms. These case studies demonstrated the ability of this approach to study relationships between different factors affecting the aneurysm wall and produced provocative observations that will be further studied with larger series. For instance, "atherosclerotic" and "hyperplastic" looking parts of the aneurysm corresponded to thicker walls and occurred in regions of recirculating flow and low wall shear stress (WSS); thin regions were associated with inflow jets, flow impingement, and high WSS; blebs had walls of varying structures, including calcified, thin, or hyperplastic walls. CONCLUSIONS The current approach enables the study of interactions of multiple factors thought to be responsible for the progressive degradation and weakening of the aneurysm wall during its evolution.
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Affiliation(s)
- Juan R Cebral
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Fernando Mut
- Bioengineering Department, Volgenau School of Engineering, George Mason University, Fairfax, Virginia, USA
| | - Piyusha Gade
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Fangzhou Cheng
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yasutaka Tobe
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Juhana Frosen
- Hemorrhagic Brain Pathology Research Group, Neurocenter, Kuopio University Hospital, Kuopio, Finland
| | - Anne M Robertson
- Mechanical Engineering and Materials Science and Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Ping Y, Gu H. A case report on middle cerebral artery aneurysm treated by rapid ventricular pacing: A CARE compliant case report. Medicine (Baltimore) 2018; 97:e13320. [PMID: 30508924 PMCID: PMC6283198 DOI: 10.1097/md.0000000000013320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
RATIONALE Cerebral aneurysm is a common cause of intracranial hemorrhage, stroke, and death. It is treated with vascular surgeries, such as coil embolism and artery clipping. However, surgery itself is a risk factor that may cause rupture of aneurysm, and leads to irreversible brain damage, and even death. Rapid ventricular pacing (RVP) is a procedure that temporarily lowers blood pressure by increasing heart rate and reducing ventricular filling time. RVP has been widely used to reduce blood vessel tension in many cardiovascular surgeries. PATIENT CONCERNS A 46-year-old man came to our hospital with intermittent right-side headache for 5 years, and left lower limb numbness for 3 months. DIAGNOSES Magnetic resonance imaging (MRI) of the head and digital subtraction angiography confirmed the diagnosis of right middle cerebral artery (MCA) aneurysm. INTERVENTIONS Considering the large size of this MCA aneurysm, RVP was used to reduce blood pressure during MCA aneurysm repair, and to lower the risk of intracranial hemorrhage during procedure. OUTCOMES Post procedure, there was no abnormality detected. Seven weeks after surgery, the patient's muscle tone of right side extremities were grade V and left side extremities were grade IV. Computed tomography angiography confirmed no MCA aneurysm. LESSONS In cases of aneurysm rupture, RVP will induce a transient "very low pressure" condition, and give a valuable time frame to clip the ruptured aneurysm. Therefore RVP is a safe and effective method to provide transient reduction of cardiac output in intracranial aneurysm patients.
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36
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Hemodynamic findings associated with intraoperative appearances of intracranial aneurysms. Neurosurg Rev 2018; 43:203-209. [DOI: 10.1007/s10143-018-1027-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 08/04/2018] [Accepted: 08/28/2018] [Indexed: 10/28/2022]
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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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38
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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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Feletti A, Wang X, Talari S, Mewada T, Mamadaliev D, Tanaka R, Yamada Y, Kei Y, Suyama D, Kawase T, Kato Y. Computational Fluid Dynamics Analysis and Correlation with Intraoperative Aneurysm Features. ACTA NEUROCHIRURGICA. SUPPLEMENT 2018; 129:3-9. [PMID: 30171307 DOI: 10.1007/978-3-319-73739-3_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
INTRODUCTION There are many controversies about computational fluid dynamics (CFD) findings and aneurysm initiation, growth, and ultimate rupture. The aim of our work was to analyze CFD data in a consecutive series of patients and to correlate them with intraoperative visual aneurysm findings. METHODS Hemoscope software (Amin, Ziosoft Corporation, Minato ward, Tokyo, Japan) was used to process images from 17 patients who underwent clipping of 18 aneurysms. Pressure (P), wall shear stress (WSS) gradient and vectors, normalized WSS, and streamlines (SL) direction and velocity were assessed. CFD data were compared to intraoperative visual findings. A total of 39 aneurysm wall areas were assessed. RESULTS Red, thin aneurysm wall areas were more often associated with low WSS. However, the association of low WSS with high P, diverging WSS vectors, direct impact of SL, and high SL velocity more frequently matched with yellow, atherosclerotic aneurysm walls. CONCLUSIONS Low WSS alone is not sufficient to determine the thickness of an aneurysm wall. Its association with other parameters might enable one to distinguish preoperatively atherosclerotic, thick areas (high P, diverging WSS vectors, high flow velocity) from thin areas with higher rupture risk (parallel WSS vectors, lower flow velocity). The changing balance between these parameters can modify the features and the risk of rupture of aneurysm wall over time.
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Affiliation(s)
- Alberto Feletti
- Department of Neurosciences, Neurosurgery Unit, NOCSAE Modena Hospital, Modena, Italy.
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan.
| | - Xiangdong Wang
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Sandeep Talari
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Tushit Mewada
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Dilshod Mamadaliev
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Riki Tanaka
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Yasuhiro Yamada
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Yamashiro Kei
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Daisuke Suyama
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Tukasa Kawase
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
| | - Yoko Kato
- Department of Neurosurgery, Fujita Health University Hospital, Nagoya, Japan
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Fujimura S, Takao H, Suzuki T, Dahmani C, Ishibashi T, Mamori H, Yamamoto M, Murayama Y. A new combined parameter predicts re-treatment for coil-embolized aneurysms: a computational fluid dynamics multivariable analysis study. J Neurointerv Surg 2017; 10:791-796. [PMID: 29246907 PMCID: PMC6204940 DOI: 10.1136/neurintsurg-2017-013433] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 11/07/2022]
Abstract
Purpose Coil embolization is a minimally invasive method used to treat cerebral aneurysms. Although this endovascular treatment has a high success rate, aneurysmal re-treatment due to recanalization remains a major problem of this method. The purpose of this study was to determine a combined parameter that can be useful for predicting aneurysmal re-treatment due to recanalization. Methods Patient-specific geometries were used to retrospectively analyze the blood flow for 26 re-treated and 74 non-retreated aneurysms. Post-operatively aneurysms were evaluated at 12-month follow-up. The hemodynamic differences between the re-treatment and non-retreatment aneurysms were analyzed before and after coil embolization using computation fluid dynamics. Basic fluid characteristics, rates of change, morphological factors of aneurysms and patient-specific clinical information were examined. Multivariable analysis and logistic regression analysis were performed to determine a combined parameter—re-treatment predictor (RP). Results Among examined hemodynamic, morphological, and clinical parameters, slight reduction of blood flow velocity rate in the aneurysm, slight increase of pressure rate at the aneurysmal neck and neck area, and hypertension were the main factors contributing to re-treatment. Notably, hemodynamic parameters between re-treatment and non-retreatment groups before embolization were similar: however, we observed significant differences between the groups in the post-embolization average velocity and the rate of reduction in this velocity in the aneurysmal dome. Conclusions The combined parameter, RP, which takes into consideration hemodynamic, morphological, and clinical parameters, accurately predicts aneurysm re-treatment. Calculation of RP before embolization may be able to predict the aneurysms that will require re-treatment.
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Affiliation(s)
- Soichiro Fujimura
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.,Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroyuki Takao
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Suzuki
- Department of Innovation for Medical Information Technology, The Jikei University School of Medicine, Tokyo, Japan.,Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Chihebeddine Dahmani
- Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan.,Sliemens Health K.K, Tokyo, Japan
| | - Toshihiro Ishibashi
- Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
| | - Hiroya Mamori
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, Division of Endovascular Neurosurgery, The Jikei University School of Medicine, Tokyo, Japan
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Petridis AK, Kaschner M, Cornelius JF, Kamp MA, Tortora A, Steiger HJ, Turowski B. A New Imaging Tool for Realtime Measurement of Flow Velocity in Intracranial Aneurysms. Clin Pract 2017; 7:975. [PMID: 28839527 PMCID: PMC5543827 DOI: 10.4081/cp.2017.975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 07/19/2017] [Indexed: 12/03/2022] Open
Abstract
With modern imaging modalities of the brain a significant number of unruptured aneurysms are detected. However, not every aneurysm is prone to rupture. Because treatment morbidity is about 10% it is crucial to identify unstable aneurysms for which treatment should be discussed. Recently, new imaging tools allow analysis of flow dynamics and wall stability have become available. It seems that they might provide additional data for better risk profiling. In this study we present a new imaging tool for analysis of flow dynamics, which calculates fluid velocity in an aneurysm (Phillips Electronics, N.V.). It may identify regions with high flow and calculate flow reduction after stenting of aneurysms. Contrast is injected with a stable injection speed of 2 mL/sec for 3 sec. Two clinical cases are illustrated. Velocity in aneurysms and areas of instability can be identified and calculated during angiography in real-time. After stenting and flow diverter deployment flow reduction in the internal carotid aneurysm was reduced by 60% and there was a reduction of about 65% in the posterior cerebral artery in the second case we are reporting. The dynamic flow software calculates the flow profile in the aneurysm immediately after contrast injection. It is a real-time, patient specific tool taking into account systole, diastole and flexibility of the vasculature. These factors are an improvement as compared to current models of computational flow dynamics. We think it is a highly efficient, user friendly tool. Further clinical studies are on their way.
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Affiliation(s)
- Athanasios K Petridis
- Department of Neurosurgery Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
| | - Marius Kaschner
- Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
| | - Jan F Cornelius
- Department of Neurosurgery Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
| | - Marcel A Kamp
- Department of Neurosurgery Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
| | - Angelo Tortora
- Department of Neurosurgery Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
| | - Hans-Jakob Steiger
- Department of Neurosurgery Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
| | - Bernd Turowski
- Institute of Neuroradiology, Heinrich Heine University Duesseldorf, Germany
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42
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Daughter Sac Formation Related to Blood Inflow Jet in an Intracranial Aneurysm. World Neurosurg 2016; 96:396-402. [DOI: 10.1016/j.wneu.2016.09.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 09/08/2016] [Accepted: 09/08/2016] [Indexed: 10/21/2022]
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43
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Suzuki T, Takao H, Fujimura S, Dahmani C, Ishibashi T, Mamori H, Fukushima N, Yamamoto M, Murayama Y. Selection of helical braided flow diverter stents based on hemodynamic performance and mechanical properties. J Neurointerv Surg 2016; 9:999-1005. [PMID: 27646987 PMCID: PMC5629929 DOI: 10.1136/neurintsurg-2016-012561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/24/2016] [Accepted: 08/29/2016] [Indexed: 11/04/2022]
Abstract
BACKGROUND Although flow diversion is a promising procedure for the treatment of aneurysms, complications have been reported and it remains poorly understood. The occurrence of adverse outcomes is known to depend on both the mechanical properties and flow reduction effects of the flow diverter stent. OBJECTIVE To clarify the possibility of designing a flow diverter stent considering both hemodynamic performance and mechanical properties. MATERIALS AND METHODS Computational fluid dynamics (CFD) simulations were conducted based on an ideal aneurysm model with flow diverters. Structural analyses of two flow diverter models exhibiting similar flow reduction effects were performed, and the radial stiffness and longitudinal flexibility were compared. RESULTS In CFD simulations, two stents-Pore2-d35 (26.77° weave angle when fully expanded, 35 μm wire thickness) and Pore3-d50 (36.65°, 50 μm respectively)-demonstrated similar flow reduction rates (68.5% spatial-averaged velocity reduction rate, 85.0% area-averaged wall shear stress reduction rate for Pore2-d35, and 68.6%, 85.4%, respectively, for Pore3-d50). However, Pore3-d50 exhibited greater radial stiffness than Pore2-d35 (40.0 vs 21.0 mN/m at a 3.5 mm outer diameter) and less longitudinal flexibility (0.903 vs 0.104 N·mm bending moments at 90°). These measurements indicate that changing the wire thickness and weave angle allows adjustment of the mechanical properties while maintaining the same degree of flow reduction effects. CONCLUSIONS The combination of CFD and structural analysis can provide promising solutions for an optimized stent. Stents exhibiting different mechanical properties but the same flow reduction effects could be designed by varying both the weave angle and wire thickness.
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Affiliation(s)
- Takashi Suzuki
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Hiroyuki Takao
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan.,Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.,Department of Innovation for Medical Information Technology, Jikei University School of Medicine, Tokyo, Japan
| | - Soichiro Fujimura
- Graduate School of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Chihebeddine Dahmani
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan.,Siemens Healthcare K.K., Tokyo, Japan
| | - Toshihiro Ishibashi
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
| | - Hiroya Mamori
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Naoya Fukushima
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Makoto Yamamoto
- Department of Mechanical Engineering, Tokyo University of Science, Tokyo, Japan
| | - Yuichi Murayama
- Department of Neurosurgery, Jikei University School of Medicine, Tokyo, Japan
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