scholarly journals Computational fluid dynamics as a risk assessment tool for aneurysm rupture

2019 ◽  
Vol 47 (1) ◽  
pp. E12 ◽  
Author(s):  
Yuichi Murayama ◽  
Soichiro Fujimura ◽  
Tomoaki Suzuki ◽  
Hiroyuki Takao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Clinical Decision Making ◽  
Assessment Tool ◽  
Clinical Decision ◽  
Aneurysm Rupture ◽  
Hemodynamic Parameters ◽  
Rupture Risk ◽  
Clinical Role ◽  
Risk Of Rupture

OBJECTIVEThe authors reviewed the clinical role of computational fluid dynamics (CFD) in assessing the risk of intracranial aneurysm rupture.METHODSA 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.RESULTSThe 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.CONCLUSIONSAlthough 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.

Computational Fluid Dynamics of a Fatal Ruptured Anterior Communicating Artery Aneurysm

2017 ◽  
Vol 78 (06) ◽  
pp. 610-616 ◽  
Author(s):  
Helena Švihlová ◽  
Alena Sejkorová ◽  
Tomáš Radovnický ◽  
Daniel Adámek ◽  
Jaroslav Hron ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Artery Aneurysm ◽  
Aneurysm Rupture ◽  
Anterior Communicating Artery ◽  
Rupture Risk ◽  
Anterior Communicating Artery Aneurysm ◽  
Computational Fluid Dynamics Cfd ◽  
Inflow Jet ◽  
Rupture Site

AbstractComputational fluid dynamics (CFD) has been studied as a tool for the stratification of aneurysm rupture risk. We performed CFD analysis in a patient operated on for a ruptured anterior communicating artery aneurysm. The point of rupture was identified during surgery. The aneurysm and blood vessels were segmented from computed tomography angiography to prepare a model for simulations. We found that the streamlines showed a concentrated inflow jet directed straight at the rupture point, and high wall shear stress was found at the point of rupture in the aneurysm sac. Thus specific local hemodynamics may be indicative of the aneurysm rupture site.

scholarly journals Computational Fluid Dynamics in Unruptured Intracranial Aneurysms

2018 ◽  
Vol 32 (2) ◽  
pp. 332-339 ◽  
Author(s):  
Maruf Matmusaev ◽  
Yasuhiro Yamada ◽  
Tsukasa Kawase ◽  
Riki Tanaka ◽  
Miyatani Kyosuke ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Intracranial Aneurysms ◽  
Thin Wall ◽  
Rupture Risk ◽  
Ct Angiogram ◽  
Aneurysm Wall ◽  
Unruptured Intracranial Aneurysms ◽  
Increased Risk ◽  
Risk Of Rupture

Abstract Introduction and Objective: Intracranial aneurysm, also known as brain aneurysm, is a cerebrovascular disorder in which weakness in the wall of a cerebral artery causes a localized dilation or ballooning of the blood vessel. There is no objective way, device or tools, of predicting rupture of aneurysm so far. Computational fluid dynamics (CFDs) was proposed as a tool to identify the rupture risk. Purpose of study: To reveal the correlation of CFD findings with intraoperative microscopic findings and prove the relevance of CFDin the prediction of rupture risk and in the management of unruptured intracranial aneurysms. Subjects and Methods: A prospective cohort study was conducted inNeurosurgery department of Fujita Health University Banbuntane Hotokukai Hospital, Nagoya, Japanduring a 3‑month period in 2018,from January to March, Ten patientswere diagnosed unruptured intracranial aneurysms (UIA). In diagnosis computed tomography (CT) angiogram, CFD and digital subtraction angiogram were included. Intraoperatively microscopic examination of the aneurysm wall was carried out and images recorded. The correlation between microscopic dome morphology and CFD information was performed. Results: Nine cases were found intraoperatively to have a higher risk of rupture based on the thinning of the wall. One cases had an atherosclerotic wall. All cases had low wall shear stress (WSS). In 90 % of cases Low WSS was able to predict the potency rupture risk in the near future. Conclusions: This study of CFD and its correlation with intraoperativefindings of the aneurysm suggested that low WSS of the aneurysm wall is associated with thin wall aneurysm and hence increased risk of aneurysm rupture. Thus CFD can be used to predict the risk of rupture of unruptured aneurysm and for planning of its treatment.

Abstract TMP29: Prediction of Wall-thinning Area in Unruptured Intracerebral Aneurysms by Computational Fluid Dynamics

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Yoshifumi Hayashi ◽  
Takanobu Yagi ◽  
Yasutaka Tobe ◽  
Yuki Iwabuchi ◽  
Momoko Yamanashi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wall Pressure ◽  
Patient Specific ◽  
Unruptured Aneurysms ◽  
Divergent Flow ◽  
Wall Thinning ◽  
Risk Of Rupture ◽  
Angiographic Data ◽  
Intracerebral Aneurysm

[Background and purpose] During a clipping surgery, an unruptured intracerebral aneurysm often presented a spatially-localized red-colored "wall-thinning" area. The wall thinning was believed to be related with the risk of rupture. The present aim is given to investigate the predictability of a wall thinning area using computational fluid dynamics (CFD). [Method] We chose 16 unruptured aneurysms (12 MCA, 4 ICA) with clipping surgery and 24 wall-thinning areas were detected from the operation video. CFD study was carried out using patient-specific angiographic data. The wall shear stress (WSS) and the wall pressure were evaluated. [Results] The WSS magnitude was found to be uncorrelated with wall thinning. On the other hand, 20 wall-thinning areas (83%) exhibited a presence of “flow impingement”, which was defined to give the spatial variation of the WSS vector to be divergent with the local elevation of the wall pressure. From CFD, 27 flow impingements were detected and classified according to the degree of divergence. Seven impingements are full-divergent and all of them (100%) are located in the wall thinning areas. The remaining 20 impingements were partial-divergent and 13 impingements of them (65%) were located in the wall thinning areas. A classification of full-/partial-divergent flow impingement was statistically significant for the prediction of wall-thinning areas (P<0.01). [Conclusions] The full-divergent flow impingement was found to be a reliable predictor of the wall thinning area in unruptured intracerebral aneurysms. The present results demonstrated the malignant nature of flow impingement for promoting the thinning of aneurysmal walls.

scholarly journals Biomechanical Rupture Risk Assessment

Aorta ◽  
2016 ◽  
Vol 04 (02) ◽  
pp. 42-60 ◽  
Author(s):  
T. Christian Gasser
Keyword(s):  
Risk Assessment ◽  
Decision Making ◽  
Validation Studies ◽  
Clinical Decision Making ◽  
Clinical Decision ◽  
Patient Treatment ◽  
Maximum Diameter ◽  
Individual Risk ◽  
Rupture Risk ◽  
Aneurysm Wall

AbstractAbdominal aortic aneurysm (AAA) rupture is a local event in the aneurysm wall that naturally demands tools to assess the risk for local wall rupture. Consequently, global parameters like the maximum diameter and its expansion over time can only give very rough risk indications; therefore, they frequently fail to predict individual risk for AAA rupture. In contrast, the Biomechanical Rupture Risk Assessment (BRRA) method investigates the wall’s risk for local rupture by quantitatively integrating many known AAA rupture risk factors like female sex, large relative expansion, intraluminal thrombus-related wall weakening, and high blood pressure. The BRRA method is almost 20 years old and has progressed considerably in recent years, it can now potentially enrich the diameter indication for AAA repair. The present paper reviews the current state of the BRRA method by summarizing its key underlying concepts (i.e., geometry modeling, biomechanical simulation, and result interpretation). Specifically, the validity of the underlying model assumptions is critically disused in relation to the intended simulation objective (i.e., a clinical AAA rupture risk assessment). Next, reported clinical BRRA validation studies are summarized, and their clinical relevance is reviewed. The BRRA method is a generic, biomechanics-based approach that provides several interfaces to incorporate information from different research disciplines. As an example, the final section of this review suggests integrating growth aspects to (potentially) further improve BRRA sensitivity and specificity. Despite the fact that no prospective validation studies are reported, a significant and still growing body of validation evidence suggests integrating the BRRA method into the clinical decision-making process (i.e., enriching diameter-based decision-making in AAA patient treatment).

Abstract WP121: An Evaluation of Hemodynamics Across Intracranial Steno-occlusive Lesions by Computational Fluid Dynamics

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Florence SY Fan ◽  
Vincent HL Ip ◽  
Alexander YL Lau ◽  
Anne YY Chan ◽  
Lisa WC Au ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Gradient ◽  
Pressure Difference ◽  
Pressure Ratio ◽  
Velocity Ratio ◽  
Strongly Correlated ◽  
Hemodynamic Parameters ◽  
Moderate Correlation ◽  
Anterior Circulation

Introduction: Intracranial atherosclerotic steno-occlusive disease (ICAS) is a major cause of stroke worldwide and portends a high risk of recurrence. Computational fluid dynamics (CFD) is a novel technique developed to solve and analyze the dynamic effects of fluid flow. We aimed to analyse hemodynamics across ICAS using CFD on processed CTA images and explore the correlation between the degree of arterial stenosis and hemodynamic flow status. Methods: We recruited patients with symptomatic ICAS from Acute Stroke Unit, Prince of Wales Hospital. All patients received CTA and DSA as vascular workup. Using CFD analysis of processed CTA images, we first defined the hemodynamic parameters, including pressure difference, pressure ratio, pressure gradient, shear strain rate ratio (SSR), wall shear stress (WSS) ratio and velocity ratio, across the stenosed vessels, and then we correlated the severity of stenosis as defined by DSA, with these parameters. Results: Among the 53 recruited patients (mean age 62.9 years, 69.8% males), 45 (85%) had lesions in the anterior circulation. The severity of stenosis showed a weak-to-moderate correlation with pressure difference (rs=0.392, p=0.004), pressure ratio (rs=-0.429, p=0.001) and pressure gradient (rs=0.419, p=0.002). There was no significant correlation between the severity of stenosis with SSR ratio, WSS ratio and velocity ratio. Among patients with anterior circulation stroke or TIA, the severity of stenosis showed a weak to moderate correlation with pressure difference (rs=0.381, p=0.01), pressure ratio (rs=-0.426, p=0.004) and pressure gradient (rs=0.407, p=0.005). For patients with posterior circulation stroke or TIA, the severity of stenosis was strongly correlated with pressure difference (rs=0.714, p=0.047) and pressure ratio (rs=-0.714, p=0.047); and very strongly correlated with velocity ratio (rs=0.833, p=0.01). Conclusions: The severity of ICAS showed only weak-to-moderate correlation with hemodynamic parameters across the culprit lesion. Thus, risk stratification and treatment based solely on stenotic severity may be inadequate. Our findings may guide further research in estimating stroke risks and selection of high-risk patients who may benefit from adjunctive treatments.

scholarly journals A Workflow for Patient-Individualized Virtual Angiogram Generation Based on CFD Simulation

2012 ◽  
Vol 2012 ◽  
pp. 1-24 ◽  
Author(s):  
Jürgen Endres ◽  
Markus Kowarschik ◽  
Thomas Redel ◽  
Puneet Sharma ◽  
Viorel Mihalef ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Blood Flow ◽  
Shear Stress ◽  
Cfd Simulation ◽  
Cerebral Aneurysms ◽  
Patient Specific ◽  
Hemodynamic Parameters ◽  
Risk Of Rupture ◽  
Computational Fluid Dynamics Cfd ◽  
Subsequent Comparison

Increasing interest is drawn on hemodynamic parameters for classifying the risk of rupture as well as treatment planning of cerebral aneurysms. A proposed method to obtain quantities such as wall shear stress, pressure, and blood flow velocity is to numerically simulate the blood flow using computational fluid dynamics (CFD) methods. For the validation of those calculated quantities, virtually generated angiograms, based on the CFD results, are increasingly used for a subsequent comparison with real, acquired angiograms. For the generation of virtual angiograms, several patient-specific parameters have to be incorporated to obtain virtual angiograms which match the acquired angiograms as best as possible. For this purpose, a workflow is presented and demonstrated involving multiple phantom and patient cases.

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