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Non-Newtonian Effect on Hemodynamic Characteristics of Blood Flow in Stented cerebral aneurysm

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Communications in Computational Physics 2013年第3期13卷 916-928页

作者： Changsheng Huang Zhenhua Chai Baochang Shi School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan 430074P.R.China

Stent placement is considered as a promising and minimally invasive technique to prevent rupture of aneurysm and favor coagulation mechanism inside the aneurysm.Many scholars study the effect of the stent on blood flow in cerebral aneurysm by numerical simulations,and usually regard blood as the Newtonian fluid,blood,however,is a kind of non-Newtonian fluid in practice.The main purpose of the present paper is to investigate the effect of non-Newtonian behavior on the hemodynamic characteristics of blood flow in stented cerebral aneurysm with lattice Boltzmann method.The Casson model is used to describe the blood non-Newtonian character,which is one of the most popular models in depicting blood fluid.In particular,hemodynamic characteristics derived with Newtonian and non-Newtonian models are studied,and compared in detail.The results show that the non-Newtonian effect gives a great influence on hemodynamic characteristics of blood flow in stented cerebral aneurysm,especially in small necked ones.

关键词： cerebral aneurysm lattice Boltzmann non-Newtonian fluid Casson model

Inflammation mediates the pathogenesis of cerebral aneurysm and becomes therapeutic target

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Neuroimmunology and Neuroinflammation 2015年第1期2卷 86-92页

作者： Tomohiro Aoki Center for Innovation in Immunoregulation Technology and Therapeutics Graduate School of MedicineKyoto UniversityKyoto 606-8501Japan

The treatment of cerebral aneurysms(CAs)is of social importance,because poor outcomes result in subarachnoid hemorrhages after rupture.However,there is currently no medical treatment available to prevent the progression and rupture of CAs,which results in a large number of patients without receiving treatment.Recent studies using human samples have revealed the presence of inflammatory responses in lesions and also the possible correlation of inflammation with CA progression or rupture.Furthermore,experimental studies using animal models of CAs have supported the notion from human studies and have clarified the crucial contribution of inflammation to the pathogenesis.In this process,a vicious cycle/positive feedback loop includes the nuclear factor-kappa B(NF-kB)activation,which plays a role in amplifying inflammatory responses to the point of chronicity.In addition,the infiltration of macrophages via NF-kB-mediated monocyte chemotactic protein 1 induction expands inflammation in whole arterial walls and contributes to the degeneration of media by producing various cytokines and tissue-destructive proteases.These series of studies have provided an important insight-antiinflammatory drugs can be therapeutically significant in the treatment of CAs.Indeed,in animal models,some drugs with an antiinflammatory effect effectively suppressed CA formation and progression,which supports this hypothesis.In addition,in human cases,some case-control studies have reported the preventive effect of statins and nonsteroidal antiinflammatory drugs on CA rupture.Therefore,the development of novel medical treatment for preventing the progression and rupture of CAs is needed in the near future.In this literature review,articles were selected by performing a PubMed search using the key words“cerebral aneurysm”and“inflammation”.

关键词： cerebral aneurysm inflammation macrophage nuclear factor‑kappa B

Biomechanical Considerations in the Unruptured cerebral aneurysm Study (UCAS Japan): Rupture Risk and True Stress of Wall

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Journal of Biosciences and Medicines 2021年第10期9卷 172-189页

作者： Fumio Nogata Yasunari Yokota Yoko Kawamura Hiroyuki Morita Yoshiyuki Uno Tetsuya Mouri William R. Walsh Takakahiko Kawamura Nigishi Hotta Kenji Kagechika Gifu University Gifu Japan Department of Electrical Electronic and Computer Engineering Faculty of Engineering Gifu University Gifu Japan Faculty of Engineering Gifu University Gifu Japan Department of General Medicine and General Internal Medicine Gifu University Graduate School of Medicine Gifu Japan Department of General Medicine Gifu Prefectural General Medical Center Gifu Japan Department of Mechanical Engineering Faculty of Engineering Gifu University Gifu Japan Prince of Wales Hospital University of New South Wales Kensington Australia Chubu Rosai Hospital Aichi Japan Diabetes and Endocrine Internal Medicine Nagoya Japan Nagoya University and Chubu Rosai Hospital Internal Medicine Nagoya Japan Toyama Prefectural Rehabilitation Hospital and Support Center for Children with Disabilities Toyama Japan

When an unruptured aneurysm is found, deciding whether to operate or follow up is one of the most important issues. There are guidelines for making the best final decision on treatment, taking into account the effectiveness of diagnostic and therapeutic devices and the risk-benefit ratio of patients, caregivers, and healthcare professionals. The guidelines evidence-based of large clinical data for this purpose are presented by national medical societies. As one of the rupture risk indicators, there is the hazard risk ratio derived by the UCAS Japan research group based on the statistical method of 6697 aneurysms in 5720 patients with cerebral aneurysms of 3 mm or more. Therefore, we investigated the biomechanical significance of this hazard risk ratio using a spherical aneurysm model. It was revealed that 1) the reason why the frequency of aneurysm rupture is relatively high up to about 10 mm, 2) the UCAS hazard risk ratio corresponds to stress of the aneurysm wall, and the true stress can be calculated by multiplying the patient’s blood pressure, and 3) the factors that cause the daughter’s sac (irregular protrusion of the aneurysm wall). In addition, our two methods for measuring the strength of the blood vessel wall of an individual patient were described.

关键词： cerebral aneurysm Rupture Risk UCAS Hazard Ratio Biomechanics

Delayed-onset adenosine deaminase deficiency with a novel synonymous mutation and a case series from China

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World Journal of Pediatrics 2023年第7期19卷 687-700页

作者： Yue Zhang Wei Liu Zhou Shu Yan Li Fei Sun Zhi-Gang Li Tong-Xin Han Hua-Wei Mao Tian-You Wang Department of Immunology Beijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthNo.56 Nan Lishi RoadXicheng DistrictBeijing 100045China Hematology Oncology Center Henan Children's HospitalChildren's Hospital Affiliated of Zhengzhou UniversityZhengzhou Children's HospitalZhengzhouChina Hematologic Disease Laboratory Beijing Pediatric Research InstituteBeijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthBeijingChina Hematology Center Beijing Children's HospitalCapital Medical UniversityNational Center for Children's HealthNo.56 Nan Lishi RoadXicheng DistrictBeijing 100045China Beijing Key Laboratory of Pediatric Hematology Oncology National Key Discipline of PediatricsCapital Medical UniversityBeijingChina Key Laboratory of Major Diseases in Children Ministry of EducationBeijingChina

Background Adenosine deaminase(ADA)is a key enzyme in the purine salvage pathway.Genetic defects of the ADA gene can cause a subtype of severe combined immunodeficiency.To date,few Chinese cases have been reported.Methods We retrospectively reviewed the medical records of patients diagnosed with ADA deficiency in Beijing Children's Hospital and summarized the previously published ADA deficiency cases from China in the literature.Results Nine patients were identified with two novel mutations(W272X and Q202=).Early-onset infection,thymic abnor-malities and failure to thrive were the most common manifestations of Chinese ADA-deficient patients.The ADA genotype has a major effect on the clinical phenotype.Notably,a novel synonymous mutation(c.606G>A,p.Q202=)was identified in a delayed-onset patient,which affected pre-mRNA splicing leading to a frameshift and premature truncation of the protein.Furthermore,the patient showed γδT cells expansion with an increased effect or phenotype,which may be associated with the delayed onset of disease.In addition,we reported cerebral aneurysm and intracranial artery stenosis for the first time in ADA deficiency.Five patients died with a median age of four months,while two patients received stem cell transplantation and are alive.Conclusions This study described the first case series of Chinese ADA-deficient patients.Early-onset infection,thymic abnormalities and failure to thrive were the most common manifestations in our patients.We identified a synonymous muta-tion that affected pre-mRNA splicing in the ADA gene,which had never been reported in ADA deficiency.Furthermore,we reported cerebral aneurysm in a delayed-onset patient for the first time.Further study is warranted to investigate the underlying mechanisms.

关键词： Adenosine deaminase deficiency cerebral aneurysm Gamma delta Severe combined immunodeficiency Synonymous mutation

Outcomes of early physiotherapy in patients with cerebral aneurysms treated by surgical clipping or endovascular embolization

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Neural Regeneration Research 2012年第24期7卷 1900-1905页

作者： Arzu Guclu-Gunduz Sevil Bilgin Nezire Kse Hakan Oruckaptan Department of Physiotherapy and Rehabilitation Faculty of Health SciencesGazi UniversityAnkaraTurkey Department of Physiotherapy and Rehabilitation Faculty of Health SciencesHacettepe UniversityAnkaraTurkey Department of Neurosurgery Faculty of MedicineHacettepe UniversityAnkaraTurkey

Early physiotherapy was given to 124 patients with ruptured or unruptured cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients were divided into four groups according to their Hunt and Hess grade at admission and aneurysm treatment modality： Group 1,Hunt and Hess grade≤II and surgical clipping;Group 2,Hunt and Hess grade≤II and endovascular embolization;Group 3,Hunt and Hess grade≥III and surgical clipping;Group 4,Hunt and Hess grade≥III and endovascular embolization.Level of consciousness was evaluated using the Glasgow Coma Scale,functional status using the Glasgow Outcome Scale,level of the mobility using the Mobility Scale for acute stroke patients,and independence in activities of daily living using the Barthel Index.After early physiotherapy,the level of consciousness and functional status improved significantly in Groups 1,3,and 4;mobility improved significantly in all groups;and independence in activities of daily living improved significantly in Groups 1 and 3.At discharge, Groups 1 and 2 had better functional status than Groups 3 and 4.Level of consciousness,functional status,mobility and independence in activities of daily living improved after early physiotherapy. These findings suggest that early physiotherapy improved the prognosis of patients with cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients with a worse clinical status at presentation had a poorer functional status at discharge.The outcome of physiotherapy was not affected by whether surgical clipping or endovascular embolization was chosen for treatment of the aneurysm.

关键词： cerebral aneurysm Hunt and Hess grade Glasgow Coma Scale Glasgow Outcome Scale functional status surgical clipping endovascular treatment physiotherapy neural regeneration

Pathological observation of brain arteries and spontaneous aneurysms in hypertensive rats

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Chinese Medical Journal 2003年第3期116卷 105-108页

作者：张东赵继宗孙异临王硕戴华浩 Douglas D.Cochrane 李京生 Department of Neurosurgery Beijing Tiantan Hospital Capital University of Medical Sciences Beijing 100050 China Neurosurgery Division St. January Central Hospital Macao China Department of Neurosurgery Children's and Women's Health Center of British Columbia 4480 Oak Street Vancouver BC V6H 3V4 Canada

Objective To investigate the role of hypertension in the pathogenesis of cerebral aneurysms in rats.Methods Twenty spontaneous hypertensive rats (SHR) and 10 Wistar-Kyoto rats (WKY) were included in this observational study. Animals were fed with normal diet and drinking water. No experimental modifications were undertaken in either group. They were sacrificed at one year of age, the bifurcations of the circle of Willis were dissected and longitudinal serial sections were prepared for light microscopic and transmission electron microscopic study.Results In the SHR group, 2 of the 20 rats formed an aneurysm respectively at the bifurcations of the basilar artery. As revealed by electron microscopy, injury at the bifurcation of the artery first occurred on the steeper side of the intimal pad. Furthermore, loss of endothelial cells, small depressions on the intima, disruptive internal elastic lamina and lymphocytes or red blood cells infiltration were noted at the steeper side of the intimal pad. No significant changes were observed in WKY group.Conclusions cerebral aneurysms can form spontaneously in SHR without ligation of the common carotid artery and without a diet containing β-aminoproprionitrile. Long-standing systemic arterial hypertension is one of the etiological factors that contributes to aneurysm formation in SHR rats.

关键词： cerebral aneurysm hypertension experimental animal model

NON-NEWTONIAN COMPUTATIONAL HEMODYNAMICS IN TWO PATIENT-SPECIFIC cerebral aneurysmS WITH DAUGHTER SACCULES

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Journal of Hydrodynamics 2010年第5期22卷 639-646页

作者： WANG Sheng-zhang CHEN Jia-liang DING Guang-hong LU Gang ZHANG Xiao-long Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China Center of Interventional Therapy Huashan Hospital Affiliated to Fudan University Shanghai 200040 China

Hemodynamic factors play important roles in the formation, progression and rupture of cerebral aneurysms, and the Wall Shear Stress （WSS） and Oscillatory Shear Index （OSI） on the aneurysms are considered to be correlated with their growth and rupture. In this article, two computational models based on patient-specific cerebral aneurysms with daughter saccule are constructed from 3D-RA image data, one is lateral aneurysm located in middle cerebral artery （CA1） and the other is terminal aneurysm located in anterior communicating artery （CA2）, The corresponding models of the two aneurysms by removing daughter saccule are established in order to investigate the initiation and growth of the daughter saccule. The flow patterns and the distributions of hemodynamic factors in the two aneurysms before and after daughter saccule is removed are obtained by solving the governing equations with the commercial CFD software Ansys CFX11.0 under the non-Newtonian fluid assumption. By analyzing the flow patterns, it is concluded that the aneurysms with daughter saccules have more complex and unstable flow patterns and hence are prone to rupture. By comparing the distribution of OSI, a hypothesis that a high OSI causes the growth of the daughter saccule is presented.

关键词： cerebral aneurysm computational hemodynamics non-Newtonian patient-specific

EFFECTS OF PARENT ARTERY SEGMENTATION AND ANEURISMALWALL ELASTICITY ON PATIENT-SPECIFIC HEMODYNAMIC SIMULATIONS

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Journal of Hydrodynamics 2011年第5期23卷 660-668页

作者： CHEN Jia-liang DING Guang-hong YANG Xin-jian LI Hai-yun Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China Beijing Institute of Neurosurgery Beijing 100050 China Department of Biomedical Engineering Capital Medical University Beijing 100050 China

It is well known that hemodynamics and wall tension play an important role in the formation, growth and rupture of aneurysms. In the present study, the authors investigated the influence of parent artery segmentation and aneurismal-wall elasticity on patient-specific hemodynamic simulations with two patient-specific cases of cerebral aneurysms. Realistic models of the aneurysms were constructed from 3-D angiography images and blood flow dynamics was studied under physiologically representative waveform of inflow. For each aneurysm three computational models were constructed： Model 1 with more extensive upstream parent artery with the rigid arterial and aneurismal wall, Model 2 with the partial upstream parent artery with the elastic arterial and aneurismal wall, Model 3 with more extensive upstream parent artery with the rigid wall for arterial wall far from the aneurysm and the elastic wall for arterial wall near the aneurysm. The results show that Model 1 could predict complex intra-aneurismal flow patterns and wall shear stress distribution in the aneurysm, but is unable to give aneurismal wall deformation and tension, Model 2 demonstrates aneurismal wall deformation and tension, but fails to properly model inflow pattern contributed by the upstream parent artery, resulting in local misunderstanding Wall Shear Stress （WSS） distribution, Model 3 can overcome limitations of the former two models, and give an overall and accurate analysis on intra-aneufismal flow patterns, wall shear stress distribution, aneurismal-wall deformation and tension. Therefore we suggest that the proper length of extensive upstream parent artery and aneurismal-wall elasticity should be considered carefully in establishing computational model to predict the intra-aneurismal hemodynamic and wall tension.

关键词： cerebral aneurysm fluid-structure interaction upstream parent artery wall tension hemodynamics

Endoscopic anatomical study on anterior communicating artery aneurysm surgery by endonasal transphenoidal approach

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Chinese Neurosurgical Journal 2016年第4期2卷 187-193页

作者： Junwei Ma Zhimin Wang Niankai Zhang Shengshan Li Dongyi Jiang Hanchun Chen Department of Neurosurgery Suzhou Kowloon Hospital Affiliated Shanghai Jiao Tong University Suzhou 266021 China Department of Otolaryngology Affiliated Hospital of Qingdao University Medical Colledge Qingdao 266003China Department of Neurosurgery Chinese Medicine Hospital of GaomiGaomi 261500 China

Endonasal transphenoidal approach by neuroendoscopy has its own advantage, such as direct access, invasive, better visualization of the anterior communicating artery aneurysm and so on. The study is to provide anatomical knowledge for anterior communicating artery aneurysm surgery by endonasal transphenoidal approach with neuroendoscopy. Take 10 skull base specimens, observe and measure the anatomical structures around anterior communicating artery. Take 10 cadaveric heads, simulate the anterior communicating artery aneurysm surgery with neuroendoscopy by endonasal transphenoidal approach. Find the natural opening of sphenoid sinus, then open the skull base, expand bone window in anterior skull base. After that, cut off the dura, find the optic nerve, optic chiasm, cisterna lamina terminalis, anterior cerebral artery, a portion of frontal lobe, anterior communicating artery complex and its important branches, such as heubner artery, hypothalamic artery, orbitofrontal artery and so on. Lift up anterior communicating artery complex and seperate arachnoid in cisterna lamina terminalis, the lamina terminalis is exposed. Block bilateral A1 of anterior cerebral artery with aneurysm clip, the anterior communicating artery complex and its important branches are in view, so we can clip anterior communicating artery aneurysm safely. Anterior communicating artery aneurysm surgery can be finished with neuroendoscopy by endonasal transphenoidal approach. The vital structures can be clearly observed with neuroendoscopy. The rhombus anatomic region formed by bilateral olfactory nerve and optic nerve is a safe surgical area. According to the calculation, the safe surgical area is about 161.48 ± 12.78 mm2. Measure the distance between the important anatomic structures in the rhombus anatomic region. By means of SPSS 17 Statistical analysis software, the measuring distance is expressed with (x ± S)mm. The anterior communicating aneurysm surgery by endonasal transphenoidal approach with neuroendoscopy has its own advantage, such as

关键词： Endoscope Anterior communicating artery cerebral aneurysm Anatomy