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.

Abstract 2731: CFD Reveals Hemodynamic Differences Between Unruptured And Ruptured Intracranial Aneurysms During Observation

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Hiroyuki Takao ◽  
Yuichi Murayama ◽  
Toshihiro Ishibashi ◽  
Ichiro Yuki ◽  
Shinobu Otsuka ◽  
...  
Keyword(s):  
Cerebral Aneurysm ◽  
Significant Risk ◽  
Cerebral Aneurysms ◽  
Aneurysm Rupture ◽  
Medium Size ◽  
Hemodynamic Parameters ◽  
Natural Risk ◽  
Risk Of Rupture ◽  
Significant Difference

Background and Purpose: Although various studies have been performed, the mechanism leading to the rupture of cerebral aneurysms has not yet been elucidated. Accurate assessment of cerebral aneurysm rupture risk is important because current treatments carry a small but significant risk that can exceed the small natural risk of rupture. Various hemodynamic parameters have been proposed for estimating the risk of rupture of cerebral aneurysms, with limited success. We evaluated several hemodynamic parameters to predict rupture in a dataset of initially unruptured aneurysms in which some aneurysms ruptured during follow-up observation. Methods: Geometry of the aneurysm and blood vessels was extracted from CTA images and analyzed using a mathematical formula for fluid flow under pulsatile blood flow conditions. Fifty side-wall internal carotid posterior communicating artery (ICA-pcom) aneurysms and fifty middle cerebral artery (MCA) bifurcation aneurysms of medium size were investigated for Energy loss (EL), Pressure Loss Coefficient (PLC), wall-shear-stress (WSS) and oscillatory shear index (OSI). During a follow-up observation period, 6 ICA-pcom and 7 MCA aneurysms ruptured (44 and 43 remained unruptured, respectively, with the same location and a similar size as the ruptured cases). Results: A significant difference in the minimum WSS between aneurysms that ruptured and those that remained unruptured was noted only in ICA aneurysms (P<0.001). EL showed higher tendency in ruptured aneurysms but statistically not significant. For PLC, a significant difference was noted in both ICA (P<0.001) and MCA (P<0.001) aneurysms. All other parameters did not show significant differences between the two groups. Conclusion: A significant difference was noted in WSSMIN only in ICA aneurysms. For PLC, a significant difference was noted in both ICA and MCA aneurysms, suggesting that PLC may be one, out of possibly other useful parameters to predict cerebral aneurysm rupture.

scholarly journals Angiographical Change of Guglielmi Detachable Coils

2004 ◽  
Vol 10 (1_suppl) ◽  
pp. 161-166 ◽  
Author(s):  
Y. Nakai ◽  
M. Sonobe ◽  
T. Takigawa ◽  
T. Yamazaki ◽  
S. Okamoto ◽  
...  
Keyword(s):  
Cerebral Aneurysm ◽  
Medical Condition ◽  
Cerebral Aneurysms ◽  
Acute Stage ◽  
Guglielmi Detachable Coils ◽  
Unruptured Aneurysms ◽  
Detachable Coils

Acute angiographical changes for preventing acute rebleeding on GDC treated cerebral aneurysms were evaluated. From December 2000 to November 2002, 48 total aneurysms in 44 consecutive patients with acute SAH. Acute angiographical evaluations were carried out in 46 aneurysms, including 42 ruptured and 4 unruptured aneurysms. Two cases were excluded because of poor medical condition. In this series, there were no rebleeding cases in acute stage. In the initial embolization for the 46 aneurysms, CO was achieved in eight aneurysms, NR in 15 aneurysms and BF in 23 aneurysms. Acute angiographical observations showed progressive thrombosis in 17 aneurysms (37%). No changes were observed in remaining 29. No recanalization was observed in this series. Only one case of BF, inside the aneurysm bleb was still observed during follow up. Additional embolization was carried out. Progressive thrombosis was frequently observed in GDC treated cerebral aneurysms during acute stage. This angiographical finding seems to show prevention of rebleeding, which is considered important for the management of GDC treatment in acutely ruptured cerebral aneurysm.

Follow-up of cerebral aneurysm embolization with hydrogel embolic system: Systematic review and meta-analysis

2015 ◽  
Vol 84 (10) ◽  
pp. 1954-1963 ◽  
Author(s):  
Zbigniew Serafin ◽  
Giovanni Di Leo ◽  
Alicja Pałys ◽  
Magdalena Nowaczewska ◽  
Wojciech Beuth ◽  
...  
Keyword(s):  
Systematic Review ◽  
Cerebral Aneurysm ◽  
Meta Analysis ◽  
Aneurysm Embolization

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.

scholarly journals Comparison of the Jcerity Endoscoper Airway with the LMA Supreme for Airway Management in Patients Undergoing Cerebral Aneurysm Embolization

2021 ◽  
Author(s):  
Junfei Zhou ◽  
Lu Li ◽  
Fang Wang ◽  
Yunqi Lv
Keyword(s):  
Laryngeal Mask Airway ◽  
Airway Management ◽  
Success Rate ◽  
Cerebral Aneurysm ◽  
Cerebral Aneurysms ◽  
Laryngeal Mask ◽  
Aneurysm Embolization ◽  
Perioperative Anticoagulation ◽  
Lma Supreme ◽  
Sealing Pressure

Abstract Background Interventional embolization of cerebral aneurysms often requires anticoagulation and antiplatelet therapy during perioperative period. A new type of laryngeal mask airway (Jcerity Endoscoper Airway)with a unique design may cause less oropharyngeal injury and bleeding for patients receiving perioperative anticoagulation. This study sought to compare the efficacy, safety and complications of Jcerity Endoscoper airwayvs LMA((Laryngeal Mask Airway) Supreme in the procedure of cerebral aneurysm embolization. Methods In this prospective, randomised clinical trial, 182 adult patients with American Society of Anesthesiologists class Ι-II scheduled for interventional embolization of cerebral aneurysms were randomly allocated into the Jcerity Endoscoper airway group and the LMA Supreme group. We compared success rate of LMA implantation, ventilation quality, airway sealing pressure, peak airway pressure, degree of blood staining, postoperative oral hemorrhage, sore throat and other complications between the groups. Results There were no significant differences between the groups in terms of success rate of LMA implantation, ventilation quality, airway sealing pressure or airway peak pressure. The LMA Supreme group showed a significantly higher degree of blood staining than the Jcerity Endoscoper airway group when the laryngeal mask airway was removed (P = 0.04), and there were also more oral hemorrhages and pharyngeal pain than in the the Jcerity Endoscoper airway group (P = 0.03,P = 0.02). No differences were observed between groups in terms of other complications related to the LMA. Conclusions The Jcerity Endoscoper airway can be safely and effectively used for airway management in patients undergoing cerebral aneurysm embolization, which can significantly reduce airway complications related to perioperative anticoagulation.

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.

The Woven EndoBridge (WEB) device: feasibility, techniques, and outcomes after FDA approval

2021 ◽  
pp. 1-7
Author(s):  
Nikolaos Mouchtouris ◽  
David Hasan ◽  
Edgar A. Samaniego ◽  
Fadi Al Saiegh ◽  
Ahmad Sweid ◽  
...  
Keyword(s):  
Cerebral Aneurysms ◽  
Arterial Phase ◽  
Unruptured Aneurysms ◽  
Fda Approval ◽  
Aneurysm Embolization ◽  
Woven Endobridge ◽  
Web Device ◽  
Wide Neck ◽  
The Web

OBJECTIVE Wide-neck bifurcation cerebral aneurysms have historically required either clip ligation or stent- or balloon-assisted coil embolization. This predicament led to the development of the Woven EndoBridge (WEB) aneurysm embolization system, a self-expanding mesh device that achieves intrasaccular flow disruption and does not require antithrombotic medications. The authors report their operative experience and 6-month follow-up occlusion outcomes with the first 115 aneurysms they treated via WEB embolization. METHODS The authors reviewed the first 115 cerebral aneurysms they treated by WEB embolization after FDA approval of the WEB embolization device (from February 2019 to January 2021). Data were collected on patient demographics and clinical presentation, aneurysm characteristics, procedural details, postembolization angiographic contrast stasis, and functional outcomes. RESULTS A total of 110 patients and 115 aneurysms were included in our study (34 ruptured and 81 unruptured aneurysms). WEB embolization was successful in 106 (92.2%) aneurysms, with a complication occurring in 6 (5.5%) patients. Contrast clearance was seen in the arterial phase in 14 (12.2%) aneurysms, in the capillary phase in 16 (13.9%), in the venous phase in 63 (54.8%), and no contrast was seen in 13 (11.3%) of the aneurysms studied. Follow-up angiography was performed on 60 (52.6%) of the aneurysms, with complete occlusion in 38 (63.3%), neck remnant in 14 (23.3%), and aneurysmal remnant in 8 (13.3%). Six (5.5%) patients required re-treatment for persistent aneurysmal residual on follow-up angiography. CONCLUSIONS The WEB device has been successfully used for the treatment of both unruptured and ruptured wide-neck bifurcation aneurysms by achieving intrasaccular flow diversion. Here, the authors have shared their experience with its unique technical considerations and device size selection, as well as critically reviewed complications and aneurysm occlusion rates.

COMPUTATIONAL INVESTIGATION OF THROMBIN CONCENTRATION IN CEREBRAL ANEURYSMS TREATED WITH FLOW-DIVERTING STENTS

2019 ◽  
Vol 19 (03) ◽  
pp. 1950007
Author(s):  
XUDONG LIU ◽  
YUNHAN CAI ◽  
LUYU SU ◽  
SHENGZHANG WANG ◽  
XINJIAN YANG
Keyword(s):  
Thrombus Formation ◽  
Flow Direction ◽  
Cerebral Aneurysms ◽  
Giant Aneurysm ◽  
Coupling Model ◽  
Patient Specific ◽  
Aneurysm Embolization ◽  
Collateral Artery ◽  
Dynamics Simulations ◽  
Small Aneurysm

Flow-diverting stent is an ongoing embolization device to treat cerebral aneurysms, and it diverts the flow direction to reduce the flow velocity inside the aneurysmal sacs and promote the thrombus formation. However, its effect for aneurysm embolization is controversial. A hemodynamic-biomedical coupling model was constructed to describe the generation and transport of thrombin in arteries, and the model was applied to investigate the variation of thrombin concentration, which plays a key role in thrombus formation, in two patient-specific cerebral aneurysm models when they are treated with Pipeline flow diverting stents. It is observed from computational fluid dynamics simulations that thrombin concentration in the aneurysmal sac without collateral artery increases significantly after Pipeline implantation, however, it has hardly any variation in the aneurysmal sac without collateral artery or in the giant aneurysmal sac after Pipeline implantation. Therefore, we believe that single Pipeline is very effective to embolize a small aneurysm without collateral artery, but cannot embolize a giant aneurysm or a small aneurysm with a collateral artery on its sac effectively.

scholarly journals Small ruptured and unruptured complex cerebral aneurysms: Single center experience of low-profile visualized intraluminal support stent

2019 ◽  
Vol 07 (04) ◽  
pp. 235-241
Author(s):  
Xianli Lv ◽  
Chuhan Jiang ◽  
Shikai Liang
Keyword(s):  
Intracranial Aneurysms ◽  
Internal Carotid ◽  
Cerebral Aneurysms ◽  
Clinical Results ◽  
Single Center Experience ◽  
Low Profile ◽  
Aneurysm Embolization ◽  
Complete Obliteration ◽  
Bleeding History

Objectives:Even though low-profile visualized intraluminal support (LVIS) device is used extensively currently and provide intraluminal support in complex cerebral aneurysm embolization, only few studies have reported its clinical results. This study presents the results of patients treated with LVIS.Patients and methods:Cerebral aneurysms with an undefined neck, fusiform shape, and blood blister-like aneurysms that were treated with LVIS between May 2017 and May 2019 were reviewed retrospectively.Results:Overall, 112 aneurysms in 104 patients were treated using LVIS, and 105 LVISs were placed. Of these, 101 aneurysms (90%) were small (< 10 mm) in size, 17 were fusiform aneurysms, and 3 were blood blister-like aneurysms. Overall, 39 patients suffered a subarachnoid hemorrhage and 65 had no bleeding history. 2 patients died of internal carotid artery (ICA) thrombosis, resulting in 1.9% mortality rate. Follow-up angiography was obtained in 68 patients (65%), and the complete obliteration rate was 98.5% in 6–12 months.Conclusion:The LVIS is a safe and effective treatment for small ruptured or unruptured complex intracranial aneurysms.

Abstract 1122‐000063: Postoperative Recanalization Factors of Coil Embolization for Cerebral Aneurysms with Comparable Volume Embolization Ratio

2021 ◽  
Vol 1 (S1) ◽  
Author(s):  
Hayato Uchikawa ◽  
Hiroyuki Takao ◽  
Soichiro Fujimura ◽  
Yuya Uchiyama ◽  
Yuma Yamanaka ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Aneurysm ◽  
High Velocity ◽  
Coil Embolization ◽  
Cerebral Aneurysms ◽  
Mean Value ◽  
Morphological Parameters ◽  
Hemodynamic Parameters ◽  
Concentrated Flow ◽  
Coil Shape

Introduction : Volume embolization ratio (VER) has been reported to be involved in postoperative recanalization of coil embolization. However, despite comparable VER, some cases remained stable, and the others showed recanalization. Hemodynamic and morphological factors, as described in previous studies, may also influence recanalization in addition to VER. In this study, we focused on cerebral aneurysms treated by coil embolization with comparable VER. Blood flow analysis using computational fluid dynamics (CFD) and geometrical measurements were performed to investigate the recanalization factors. Methods : We focused on the aneurysms that underwent coil embolization with 15–20% VER. The criteria for the case selection were that the size of the aneurysms was 5–10 mm and that the aneurysm was treated by only coil (i.e., the stent‐assisted cases were excluded). Aneurysms that recanalized after coil embolization and underwent additional coil deployment were defined as “recanalized”, and aneurysms that remained stable after coil embolization without coil compaction were defined as “stable”. Finally, we selected 7 recanalized cases (ICA: 1, MCA: 3, ACA: 3) and 18 stable cases (ICA: 6, MCA: 3, ACA: 9). CFD analysis and morphometry were performed on the vessel geometry after coil embolization. The coil shape was modeled by the virtual coil technique. We calculated three morphological parameters and 34 hemodynamic parameters, then we compared them between the recanalized and stable cases using the Mann‐Whitney U test to identify recanalization factors. In addition, we reconstructed the coil shape from medical images and compared its structure and flow characters for stable and recanalized cases. Results : The average VER for the cases analyzed in this study were 16.7% for recanalized cases and 17.7% for stable cases. As hemodynamic parameters, the spatially averaged velocity normal to the neck plane into the cerebral aneurysm ( NV neck ), and the ratio of the area where blood flows into the cerebral aneurysm after the coil embolization to the area of the neck surface (inflow area ratio: IAR) showed significant difference. Although the hemodynamic parameters were significantly different, morphological parameters did not show statistically significance. In the recanalized case, NV neck tended to be higher (mean value, recanalized: 0.931, stable: 0.822, P < 0.05), and IAR tended to be lower (mean value, recanalized: 0.319, stable: 0.408, P < 0.01). The high NV neck and low IAR indicate that the aneurysm had concentrated flow with a high velocity at the neck surface. There was the concentrated blood flow with the high velocity that collided with the modeled coil in a CFD result for the recanalized case. The area where the blood flow impinged on the modeled coil coincided with the compacted coil region reconstructed from medical images. Therefore, a large force on the coil indicated by these hemodynamic parameters may cause the postoperative recanalization. Conclusions : Even with the same level of VER, there was a possibility of recanalization in aneurysms with a high velocity and concentrated flow into the aneurysm. It is necessary to consider not only VER but also hemodynamic factors to investigate recanalization factors after the coil embolization.

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