On Non-Newtonian Effects in Cerebral Aneurysms: A Computational Study on 12 Patient Specific Aneurysms

2012 ◽  
Author(s):  
Øyvind Evju ◽  
Kent-Andre Mardal ◽  
Kristian Valen-Sendstad
Keyword(s):  
Subarachnoid Hemorrhage ◽  
High Risk ◽  
Mortality Rate ◽  
Cerebral Aneurysm ◽  
Computational Study ◽  
Cerebral Aneurysms ◽  
Life Time ◽  
Patient Specific

The rupture of a cerebral aneurysm may cause subarachnoid hemorrhage (SAH), a type of stroke associated with a high risk of morbidity, and a mortality rate as high as 50% within 30 days. Cerebral aneurysms are relatively common. Roughly 6% of the population develop such during a life-time ([1]) and the average age of SAH is 51 years.

A Simulation Study on the Growth of Cerebral Aneurysms

2007 ◽  
Author(s):  
Y. Shimogonya ◽  
Y. Imai ◽  
T. Ishikawa ◽  
T. Yamaguchi
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebrovascular Disease ◽  
Cerebral Aneurysm ◽  
Simulation Study ◽  
Arterial Wall ◽  
Clinical Medicine ◽  
Cerebral Aneurysms ◽  
Important Disease

Cerebral aneurysm is a cerebrovascular disease characterized by the local balloon-shaped expansion of the arterial wall. It is an extremely important disease on the clinical medicine, because the rupture of the cerebral aneurysm causes serious pathologic conditions such as the subarachnoid hemorrhage.

A Theoretical Model for Saccular Cerebral Aneurysm Growth: Deformation and Stress Analysis

2007 ◽  
Author(s):  
Martin Kroon ◽  
Gerhard Holzapfel
Keyword(s):  
Cerebral Aneurysm ◽  
Cerebral Aneurysms ◽  
Structural Features ◽  
Constitutive Behavior ◽  
Patient Specific ◽  
Western World ◽  
Specific Information ◽  
Aneurysm Wall ◽  
Aneurysm Growth ◽  
Size Criterion

Aneurysms are abnormal dilatations of arteries, and these lesions are found almost exclusively in humans. Saccular cerebral aneurysms occur most frequently in the Circle of Willis, which is a circuit of arteries supplying the brain with blood. Aneurysms of this kind appear in a few percent of the human population in the Western world. Only a few percent of these lesions do actually rupture, but once rupture occurs the consequences are severe, often with death as outcome. Once a cerebral aneurysm is detected, clinicians need to decide whether operation is required or not. These decisions are mainly based on the size of the aneurysm, where larger aneurysms are considered to be more critical than smaller ones. This size criterion is, however, not very reliable, and criteria based on mechanical fields (stress or strain) of the aneurysm should be taken into account in the decision. This, however, requires knowledge of the constitutive behavior of the aneurysm wall, together with patient-specific information regarding geometry and boundary conditions. In order to be able to model the constitutive behavior of an aneurysm, the structural features of the aneurysm wall need to be determined. Knowledge of the etiology of the aneurysm may here provide important insights.

Effects of blood flow characteristics on rupture of cerebral aneurysm: Computational study

2021 ◽  
pp. 2150143
Author(s):  
Xiao-Yong Shen ◽  
M. Barzegar Gerdroodbary ◽  
Amin Poozesh ◽  
Amir Musa Abazari ◽  
S. Misagh Imani
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
High Risk ◽  
Wall Shear Stress ◽  
Flow Pattern ◽  
Cerebral Aneurysm ◽  
Computational Study ◽  
Fluid Dynamic ◽  
Aneurysm Wall ◽  
Wall Shear

In recent decades, cardiovascular disease and stroke are recognized as the most important reason for the high death rate. Irregular bloodstream and the circulatory system are the main reason for this issue. In this paper, Computational Fluid dynamic method is employed to study the impacts of the flow pattern inside the cerebral aneurysm for detection of the hemorrhage of the aneurysm. To achieve a reliable outcome, blood flow is considered as a non-Newtonian fluid with a power-law model. In this study, the influence of the blood viscosity and velocity on the pressure distribution and average wall shear stress (AWSS) are comprehensively studied. Moreover, the flow pattern inside the aneurysm is investigated to obtain the high-risk regions for the rupture of the aneurysm. Our results indicate that the wall shear stress (WSS) increases with increasing blood flow velocity. Furthermore, the risk of aneurysm rupture is considerably increased when the AWSS increases more than 0.6. Indeed, the blood flow with high viscosity expands the high-risk region on the wall of the aneurysm. Blood flow indicates that the angle of the incoming bloodstream is substantially effective in the high-risk region on the aneurysm wall. The augmentation of the blood velocity and vortices considerably increases the risk of hemorrhage of the aneurysm.

Diagnostic yield of computed tomography angiography and magnetic resonance angiography in patients with catheter angiography–negative subarachnoid hemorrhage

2012 ◽  
Vol 117 (2) ◽  
pp. 309-315 ◽  
Author(s):  
Josser E. Delgado Almandoz ◽  
Bharathi D. Jagadeesan ◽  
Daniel Refai ◽  
Christopher J. Moran ◽  
DeWitte T. Cross ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Subarachnoid Hemorrhage ◽  
Magnetic Resonance ◽  
Magnetic Resonance Angiography ◽  
Cerebral Aneurysm ◽  
Computed Tomography Angiography ◽  
Diagnostic Yield ◽  
Cerebral Aneurysms ◽  
Valuable Adjunct ◽  
Noncontrast Ct

Object The yield of CT angiography (CTA) and MR angiography (MRA) in patients with subarachnoid hemorrhage (SAH) who have a negative initial catheter angiogram is currently not well understood. This study aims to determine the yield of CTA and MRA in a prospective cohort of patients with SAH and a negative initial catheter angiogram. Methods From January 1, 2005, until September 1, 2010, the authors instituted a prospective protocol in which patients with SAH—as documented by noncontrast CT or CSF xanthochromia and a negative initial catheter angiogram— were evaluated using CTA and MRA to assess for causative cerebral aneurysms. Two neuroradiologists independently evaluated the noncontrast CT scans to determine the SAH pattern (perimesencephalic or not) and the CT and MR angiograms to assess for causative cerebral aneurysms. Results Seventy-seven patients were included, with a mean age of 52.8 years (median 54 years, range 19–88 years). Fifty patients were female (64.9%) and 27 male (35.1%). Forty-three patients had nonperimesencephalic SAH (55.8%), 29 patients had perimesencephalic SAH (37.7%), and 5 patients had CSF xanthochromia (6.5%). Computed tomography angiography demonstrated a causative cerebral aneurysm in 4 patients (5.2% yield), all of whom had nonperimesencephalic SAH (9.3% yield). Mean aneurysm size was 2.6 mm (range 2.1–3.3 mm). Magnetic resonance angiography demonstrated only 1 of these aneurysms. No causative cerebral aneurysms were found in patients with perimesencephalic SAH or CSF xanthochromia. Conclusions Computed tomography angiography is a valuable adjunct in the evaluation of patients with nonperimesencephalic SAH who have a negative initial catheter angiogram, demonstrating a causative cerebral aneurysm in 9.3% of patients.

Hemodynamics of Cerebral Aneurysms: Connecting Medical Imaging and Biomechanical Analysis

2020 ◽  
Vol 22 (1) ◽  
pp. 231-256 ◽  
Author(s):  
Vitaliy L. Rayz ◽  
Aaron A. Cohen-Gadol
Keyword(s):  
Disease Progression ◽  
Cerebral Aneurysm ◽  
Clinical Decision Making ◽  
Treatment Guidelines ◽  
Flow Analysis ◽  
Cerebral Aneurysms ◽  
Biomechanical Analysis ◽  
Morphological Data ◽  
Risk Scores ◽  
Patient Specific

In the last two decades, numerous studies have conducted patient-specific computations of blood flow dynamics in cerebral aneurysms and reported correlations between various hemodynamic metrics and aneurysmal disease progression or treatment outcomes. Nevertheless, intra-aneurysmal flow analysis has not been adopted in current clinical practice, and hemodynamic factors usually are not considered in clinical decision making. This review presents the state of the art in cerebral aneurysm imaging and image-based modeling, discussing the advantages and limitations of each approach and focusing on the translational value of hemodynamic analysis. Combining imaging and modeling data obtained from different flow modalities can improve the accuracy and fidelity of resulting velocity fields and flow-derived factors that are thought to affect aneurysmal disease progression. It is expected that predictive models utilizing hemodynamic factors in combination with patient medical history and morphological data will outperform current risk scores and treatment guidelines. Possible future directions include novel approaches enabling data assimilation and multimodality analysis of cerebral aneurysm hemodynamics.

Investigation on a Relationship Between Hemodynamics and Wall-Thinning in an Unruptured Human Cerebral Aneurysm

2012 ◽  
Author(s):  
Yasutaka Tobe ◽  
Takanobu Yagi ◽  
Sara Takahashi ◽  
Yuki Iwabuchi ◽  
Momoko Yamanashi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Aneurysm ◽  
Medical Images ◽  
Cerebral Aneurysms ◽  
Flow Simulation ◽  
Patient Specific ◽  
Thin Walled Structures ◽  
Aneurysm Wall ◽  
Thin Walled ◽  
The Relationship

Recent studies of cerebral aneurysms are held using the blood flow simulation with patient-specific luminal geometries. In the study of development of cerebral aneurysms, wall shear stress (WSS) is focused as one of the key factors1–2. But the answer to the relationship between the extension of aneurysm and the theory of low WSS and high WSS still remains a question. One reason this question remains unsolved is because the current research about the cerebral aneurysms are held only using the vascular geometry developed from the medical images. From the intra-operative observation of cerebral aneurysms, the appearance of the cerebral aneurysm is not unified. Certain parts of the cerebral aneurysm have thin-walled structures where the blood flow of the aneurysm can be observed through the aneurysm wall. These differences in the wall structures cannot be predicted from the medical images. The purpose of this study is to see the relationship between hemodynamic patterns and thin-walled structure in human cerebral aneurysms.

scholarly journals Subarachnoid hemorrhage secondary to Brucella-induced cerebral aneurysm: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yanyan Guan ◽  
Nannan Xu ◽  
Yongyuan Yao ◽  
Feng Zheng ◽  
Fengzhe Chen ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Subarachnoid Hemorrhage ◽  
Cerebral Aneurysm ◽  
Brucella Melitensis ◽  
Cerebral Aneurysms ◽  
Aneurysm Rupture ◽  
Recurrent Fever ◽  
Elevated Protein ◽  
History Of ◽  
The Central Nervous System

Abstract Background Brucellosis is a common zoonotic disease that is prevalent in many areas worldwide. This infectious disease can occasionally affect the central nervous system but intracranial arteries are rarely involved. Case presentation A 17-year-old female who had a history of recurrent fever for 1 month was admitted for subarachnoid hemorrhage due to cerebral aneurysm rupture. Surgery was performed to fix the aneurysm, but the patient had persistent fever after the surgery. Cerebrospinal fluid testing showed a high white blood cell count and elevated protein level but no pathogen was identified in the first two tests. Brucella melitensis was identified in the third cerebrospinal fluid culture, and a diagnosis of brucellosis was finally rendered. The patient was subsequently treated with anti-Brucella medications and her symptoms improved significantly at the last follow-up. Conclusion Although extremely rare, Brucella-induced cerebral aneurysms can occur and this should be considered in the differential diagnosis of cerebrovascular accidents, especially in Brucella epidemic areas.

Multiple ruptured cerebral aneurysms in a child with Takayasu arteritis

2008 ◽  
Vol 1 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Suresh N. Magge ◽  
H. Isaac Chen ◽  
Michael F. Stiefel ◽  
Linda Ernst ◽  
Ann Marie Cahill ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Aneurysm ◽  
Takayasu Arteritis ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Cerebral Aneurysms ◽  
Artery Aneurysm ◽  
Anterior Communicating Artery ◽  
Rare Presentation ◽  
Anterior Communicating Artery Aneurysm ◽  
Clip Application

✓The authors report the case of an 18-month-old girl who presented with a ruptured anterior communicating artery aneurysm, and who was later diagnosed with Takayasu arteritis. Her initial aneurysm was successfully treated with clip application. However, over a 6-month period she had multiple ruptures from new and rapidly recurring aneurysms adjacent to the clips. These aneurysms were treated with repeated craniotomy and clip application and then with endovascular coil placement. Aneurysmal subarachnoid hemorrhage is a rare presentation of Takayasu arteritis. To the authors' knowledge, this is the youngest reported patient with Takayasu arteritis to present with a ruptured cerebral aneurysm.

scholarly journals Hemodynamics of Cerebral Aneurysms: Computational Analyses of Aneurysm Progress and Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Woowon Jeong ◽  
Kyehan Rhee
Keyword(s):  
Cerebral Aneurysm ◽  
Computational Analysis ◽  
Cerebral Aneurysms ◽  
Vascular Diseases ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Aneurysm Embolization ◽  
Mechanical Factors ◽  
Computational Analyses

The progression of a cerebral aneurysm involves degenerative arterial wall remodeling. Various hemodynamic parameters are suspected to be major mechanical factors related to the genesis and progression of vascular diseases. Flow alterations caused by the insertion of coils and stents for interventional aneurysm treatment may affect the aneurysm embolization process. Therefore, knowledge of hemodynamic parameters may provide physicians with an advanced understanding of aneurysm progression and rupture, as well as the effectiveness of endovascular treatments. Progress in medical imaging and information technology has enabled the prediction of flow fields in the patient-specific blood vessels using computational analysis. In this paper, recent computational hemodynamic studies on cerebral aneurysm initiation, progress, and rupture are reviewed. State-of-the-art computational aneurysmal flow analyses after coiling and stenting are also summarized. We expect the computational analysis of hemodynamics in cerebral aneurysms to provide valuable information for planning and follow-up decisions for treatment.

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