scholarly journals Flow-induced, inflammation-mediated arterial wall remodeling in the formation and progression of intracranial aneurysms

2019 ◽  
Vol 47 (1) ◽  
pp. E21 ◽  
Author(s):  
Juhana Frösen ◽  
Juan Cebral ◽  
Anne M. Robertson ◽  
Tomohiro Aoki
Keyword(s):  
Drug Therapy ◽  
Intracranial Aneurysms ◽  
Arterial Wall ◽  
Macrophage Infiltration ◽  
Patient Specific ◽  
Diagnostic Tools ◽  
Flow Conditions ◽  
Internal Elastic Lamina ◽  
Specific Flow ◽  
Unruptured Intracranial Aneurysms

OBJECTIVEUnruptured intracranial aneurysms (UIAs) are relatively common lesions that may cause devastating intracranial hemorrhage, thus producing considerable suffering and anxiety in those affected by the disease or an increased likelihood of developing it. Advances in the knowledge of the pathobiology behind intracranial aneurysm (IA) formation, progression, and rupture have led to preclinical testing of drug therapies that would prevent IA formation or progression. In parallel, novel biologically based diagnostic tools to estimate rupture risk are approaching clinical use. Arterial wall remodeling, triggered by flow and intramural stresses and mediated by inflammation, is relevant to both.METHODSThis review discusses the basis of flow-driven vessel remodeling and translates that knowledge to the observations made on the mechanisms of IA initiation and progression on studies using animal models of induced IA formation, study of human IA tissue samples, and study of patient-derived computational fluid dynamics models.RESULTSBlood flow conditions leading to high wall shear stress (WSS) activate proinflammatory signaling in endothelial cells that recruits macrophages to the site exposed to high WSS, especially through macrophage chemoattractant protein 1 (MCP1). This macrophage infiltration leads to protease expression, which disrupts the internal elastic lamina and collagen matrix, leading to focal outward bulging of the wall and IA initiation. For the IA to grow, collagen remodeling and smooth muscle cell (SMC) proliferation are essential, because the fact that collagen does not distend much prevents the passive dilation of a focal weakness to a sizable IA. Chronic macrophage infiltration of the IA wall promotes this SMC-mediated growth and is a potential target for drug therapy. Once the IA wall grows, it is subjected to changes in wall tension and flow conditions as a result of the change in geometry and has to remodel accordingly to avoid rupture. Flow affects this remodeling process.CONCLUSIONSFlow triggers an inflammatory reaction that predisposes the arterial wall to IA initiation and growth and affects the associated remodeling of the UIA wall. This chronic inflammation is a putative target for drug therapy that would stabilize UIAs or prevent UIA formation. Moreover, once this coupling between IA wall remodeling and flow is understood, data from patient-specific flow models can be gathered as part of the diagnostic workup and utilized to improve risk assessment for UIA initiation, progression, and eventual rupture.

Does the DSA reconstruction kernel affect hemodynamic predictions in intracranial aneurysms? An analysis of geometry and blood flow variations

2017 ◽  
Vol 10 (3) ◽  
pp. 290-296 ◽  
Author(s):  
P Berg ◽  
S Saalfeld ◽  
S Voß ◽  
T Redel ◽  
B Preim ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intracranial Aneurysms ◽  
Three Dimensional ◽  
Patient Specific ◽  
Parent Artery ◽  
Imaging Data ◽  
Specific Flow ◽  
Aneurysm Neck ◽  
Velocity Magnitude ◽  
Reconstruction Kernel

BackgroundComputational fluid dynamics (CFD) blood flow predictions in intracranial aneurysms promise great potential to reveal patient-specific flow structures. Since the workflow from image acquisition to the final result includes various processing steps, quantifications of the individual introduced potential error sources are required.MethodsThree-dimensional (3D) reconstruction of the acquired imaging data as input to 3D model generation was evaluated. Six different reconstruction modes for 3D digital subtraction angiography (DSA) acquisitions were applied to eight patient-specific aneurysms. Segmentations were extracted to compare the 3D luminal surfaces. Time-dependent CFD simulations were carried out in all 48 configurations to assess the velocity and wall shear stress (WSS) variability due to the choice of reconstruction kernel.ResultsAll kernels yielded good segmentation agreement in the parent artery; deviations of the luminal surface were present at the aneurysm neck (up to 34.18%) and in distal or perforating arteries. Observations included pseudostenoses as well as noisy surfaces, depending on the selected reconstruction kernel. Consequently, the hemodynamic predictions show a mean SD of 11.09% for the aneurysm neck inflow rate, 5.07% for the centerline-based velocity magnitude, and 17.83%/9.53% for the mean/max aneurysmal WSS, respectively. In particular, vessel sections distal to the aneurysms yielded stronger variations of the CFD values.ConclusionsThe choice of reconstruction kernel for DSA data influences the segmentation result, especially for small arteries. Therefore, if precise morphology measurements or blood flow descriptions are desired, a specific reconstruction setting is required. Furthermore, research groups should be encouraged to denominate the kernel types used in future hemodynamic studies.

Numerical Simulations of Flow in Cerebral Aneurysms: Comparison of CFD Results and In Vivo MRI Measurements

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Vitaliy L. Rayz ◽  
Loic Boussel ◽  
Gabriel Acevedo-Bolton ◽  
Alastair J. Martin ◽  
William L. Young ◽  
...  
Keyword(s):  
Flow Fields ◽  
Patient Specific ◽  
Flow Ratio ◽  
Flow Conditions ◽  
Velocity Measurements ◽  
Cfd Simulations ◽  
Specific Flow ◽  
Inlet Flow ◽  
Good Agreement

Computational fluid dynamics (CFD) methods can be used to compute the velocity field in patient-specific vascular geometries for pulsatile physiological flow. Those simulations require geometric and hemodynamic boundary values. The purpose of this study is to demonstrate that CFD models constructed from patient-specific magnetic resonance (MR) angiography and velocimetry data predict flow fields that are in good agreement with in vivo measurements and therefore can provide valuable information for clinicians. The effect of the inlet flow rate conditions on calculated velocity fields was investigated. We assessed the internal consistency of our approach by comparing CFD predictions of the in-plane velocity field to the corresponding in vivo MR velocimetry measurements. Patient-specific surface models of four basilar artery aneurysms were constructed from contrast-enhanced MR angiography data. CFD simulations were carried out in those models using patient-specific flow conditions extracted from MR velocity measurements of flow in the inlet vessels. The simulation results computed for slices through the vasculature of interest were compared with in-plane velocity measurements acquired with phase-contrast MR imaging in vivo. The sensitivity of the flow fields to inlet flow ratio variations was assessed by simulating five different inlet flow scenarios for each of the basilar aneurysm models. In the majority of cases, altering the inlet flow ratio caused major changes in the flow fields predicted in the aneurysm. A good agreement was found between the flow fields measured in vivo using the in-plane MR velocimetry technique and those predicted with CFD simulations. The study serves to demonstrate the consistency and reliability of both MR imaging and numerical modeling methods. The results demonstrate the clinical relevance of computational models and suggest that realistic patient-specific flow conditions are required for numerical simulations of the flow in aneurysmal blood vessels.

Factors influencing management of unruptured intracranial aneurysms: an analysis of 424 consecutive patients

2017 ◽  
Vol 127 (1) ◽  
pp. 96-101 ◽  
Author(s):  
Jian Guan ◽  
Michael Karsy ◽  
William T. Couldwell ◽  
Richard H. Schmidt ◽  
Philipp Taussky ◽  
...  
Keyword(s):  
Charlson Comorbidity Index ◽  
Intracranial Aneurysms ◽  
Medical Center ◽  
Aneurysm Rupture ◽  
Patient Treatment ◽  
Patient Specific ◽  
Multiple Aneurysms ◽  
Aneurysm Size ◽  
Unruptured Intracranial Aneurysms ◽  
Comorbidity Index

OBJECTIVEThe choice between treating and observing unruptured intracranial aneurysms is often difficult, with little guidance on which variables should influence decision making on a patient-by-patient basis. Here, the authors compared demographic variables, aneurysm-related variables, and comorbidities in patients who received microsurgical or endovascular treatment and those who were conservatively managed to determine which factors push the surgeon toward recommending treatment.METHODSA retrospective chart review was conducted of all patients diagnosed with an unruptured intracranial aneurysm at their institution between January 1, 2013, and January 1, 2016. These patients were dichotomized based on whether their aneurysm was treated. Demographic, geographic, socioeconomic, comorbidity, and aneurysm-related information was analyzed to assess which factors were associated with the decision to treat.RESULTSA total of 424 patients were identified, 163 who were treated surgically or endovascularly and 261 who were managed conservatively. In a multivariable model, an age < 65 years (OR 2.913, 95% CI 1.298–6.541, p = 0.010), a lower Charlson Comorbidity Index (OR 1.536, 95% CI 1.274–1.855, p < 0.001), a larger aneurysm size (OR 1.176, 95% CI 1.100–1.257, p < 0.001), multiple aneurysms (OR 2.093, 95% CI 1.121–3.907, p = 0.020), a white race (OR 2.288, 95% CI 1.245–4.204, p = 0.008), and living further from the medical center (OR 2.125, 95% CI 1.281–3.522, p = 0.003) were all associated with the decision to treat rather than observe.CONCLUSIONSWhereas several factors were expected to be considered in the decision to treat unruptured intracranial aneurysms, including age, Charlson Comorbidity Index, aneurysm size, and multiple aneurysms, other factors such as race and proximity to the medical center were unanticipated. Further studies are needed to identify such biases in patient treatment and improve treatment delineation based on patient-specific aneurysm rupture risk.

scholarly journals Development of an Intravascular Doppler Optical Coherence Tomography Imaging Technique for Neurovascular Applications

2021 ◽  
Author(s):  
Barry Vuong
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Intracranial Aneurysm ◽  
Intracranial Aneurysms ◽  
Fluid Dynamic ◽  
Patient Specific ◽  
Optical Coherence ◽  
Specific Flow ◽  
Arterial Lumen ◽  
Risk Of Rupture

The rupture of an intracranial aneurysm can cause spontaneous subarachnoid hemorrhage and result in sudden death. A large portion of intracranial aneurysms occurs near the center of the head, at the skull base, which poses significant technical challenge to neurosurgeons due to limited accessibility. The utilization of angiography is prominent during the treatment of intracranial aneurysms. However, malapposition of stent or incomplete packing of the intracranial aneurysm can be difficult to assess with angiography, and could lead to severe postoperative complications. As a result, angiography may not be sufficient in determining the risk of rupture as the compensatory mechanisms are known to occur at the microstructural level due to the local hemodynamics in the arterial lumen, as well as in evaluating the intraoperative treatment. In this work, we describe a method for assessing intracranial aneurysm through the evaluation of blood flow within the lumen and morphological structures of the arterial wall with optical coherence tomography (OCT). Sterile intravascular fiber-optic catheters can be introduced in the artery to detect blood flow. Prior to this work, limited investigations of catheter based Doppler OCT (DOCT) were reported. A novel signal processing technique was developed to further reduce the effect of Doppler noise within a catheter based DOCT system. This technique consisted of splitting the interferogram of an OCT signal prior to estimating the Doppler shift. This split spectrum DOCT (ssDOCT) method was evaluated through flow models and porcine models, as well as through the correlation between ssDOCT algorithm and computational fluid dynamic (CFD) models. It was observed that ssDOCT provided improved Doppler artefact suppression over the conventional DOCT technique. ssDOCT also provided the ability to estimate lower velocities within the DOCT image to measure the hemodynamic patterns around stent struts in both the internal carotid and patient specific flow phantoms. An OCT imaging study was also conducted consisting of surgically resected human intracranial aneurysms. Further enhancement of the detection of these key morphological structures was demonstrated by an optical-attenuation imaging variant of OCT. The presented techniques could provide further insights to the cause of intracranial aneurysm rupture and vascular healing mechanisms.

scholarly journals Development of an Intravascular Doppler Optical Coherence Tomography Imaging Technique for Neurovascular Applications

2021 ◽  
Author(s):  
Barry Vuong
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Intracranial Aneurysm ◽  
Intracranial Aneurysms ◽  
Fluid Dynamic ◽  
Patient Specific ◽  
Optical Coherence ◽  
Specific Flow ◽  
Arterial Lumen ◽  
Risk Of Rupture

The rupture of an intracranial aneurysm can cause spontaneous subarachnoid hemorrhage and result in sudden death. A large portion of intracranial aneurysms occurs near the center of the head, at the skull base, which poses significant technical challenge to neurosurgeons due to limited accessibility. The utilization of angiography is prominent during the treatment of intracranial aneurysms. However, malapposition of stent or incomplete packing of the intracranial aneurysm can be difficult to assess with angiography, and could lead to severe postoperative complications. As a result, angiography may not be sufficient in determining the risk of rupture as the compensatory mechanisms are known to occur at the microstructural level due to the local hemodynamics in the arterial lumen, as well as in evaluating the intraoperative treatment. In this work, we describe a method for assessing intracranial aneurysm through the evaluation of blood flow within the lumen and morphological structures of the arterial wall with optical coherence tomography (OCT). Sterile intravascular fiber-optic catheters can be introduced in the artery to detect blood flow. Prior to this work, limited investigations of catheter based Doppler OCT (DOCT) were reported. A novel signal processing technique was developed to further reduce the effect of Doppler noise within a catheter based DOCT system. This technique consisted of splitting the interferogram of an OCT signal prior to estimating the Doppler shift. This split spectrum DOCT (ssDOCT) method was evaluated through flow models and porcine models, as well as through the correlation between ssDOCT algorithm and computational fluid dynamic (CFD) models. It was observed that ssDOCT provided improved Doppler artefact suppression over the conventional DOCT technique. ssDOCT also provided the ability to estimate lower velocities within the DOCT image to measure the hemodynamic patterns around stent struts in both the internal carotid and patient specific flow phantoms. An OCT imaging study was also conducted consisting of surgically resected human intracranial aneurysms. Further enhancement of the detection of these key morphological structures was demonstrated by an optical-attenuation imaging variant of OCT. The presented techniques could provide further insights to the cause of intracranial aneurysm rupture and vascular healing mechanisms.

scholarly journals Development of an Intravascular Doppler Optical Coherence Tomography Imaging Technique for Neurovascular Applications

2021 ◽  
Author(s):  
Barry Vuong
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Intracranial Aneurysm ◽  
Intracranial Aneurysms ◽  
Fluid Dynamic ◽  
Patient Specific ◽  
Optical Coherence ◽  
Specific Flow ◽  
Arterial Lumen ◽  
Risk Of Rupture

The rupture of an intracranial aneurysm can cause spontaneous subarachnoid hemorrhage and result in sudden death. A large portion of intracranial aneurysms occurs near the center of the head, at the skull base, which poses significant technical challenge to neurosurgeons due to limited accessibility. The utilization of angiography is prominent during the treatment of intracranial aneurysms. However, malapposition of stent or incomplete packing of the intracranial aneurysm can be difficult to assess with angiography, and could lead to severe postoperative complications. As a result, angiography may not be sufficient in determining the risk of rupture as the compensatory mechanisms are known to occur at the microstructural level due to the local hemodynamics in the arterial lumen, as well as in evaluating the intraoperative treatment. In this work, we describe a method for assessing intracranial aneurysm through the evaluation of blood flow within the lumen and morphological structures of the arterial wall with optical coherence tomography (OCT). Sterile intravascular fiber-optic catheters can be introduced in the artery to detect blood flow. Prior to this work, limited investigations of catheter based Doppler OCT (DOCT) were reported. A novel signal processing technique was developed to further reduce the effect of Doppler noise within a catheter based DOCT system. This technique consisted of splitting the interferogram of an OCT signal prior to estimating the Doppler shift. This split spectrum DOCT (ssDOCT) method was evaluated through flow models and porcine models, as well as through the correlation between ssDOCT algorithm and computational fluid dynamic (CFD) models. It was observed that ssDOCT provided improved Doppler artefact suppression over the conventional DOCT technique. ssDOCT also provided the ability to estimate lower velocities within the DOCT image to measure the hemodynamic patterns around stent struts in both the internal carotid and patient specific flow phantoms. An OCT imaging study was also conducted consisting of surgically resected human intracranial aneurysms. Further enhancement of the detection of these key morphological structures was demonstrated by an optical-attenuation imaging variant of OCT. The presented techniques could provide further insights to the cause of intracranial aneurysm rupture and vascular healing mechanisms.

Intracranial aneurysms in sickle-cell anemia: clinical features and pathogenesis

1991 ◽  
Vol 75 (3) ◽  
pp. 356-363 ◽  
Author(s):  
Nelson M. Oyesiku ◽  
Daniel L. Barrow ◽  
James R. Eckman ◽  
Suzie C. Tindall ◽  
Austin R. T. Colohan
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
World Literature ◽  
Intracranial Aneurysms ◽  
Arterial Wall ◽  
Muscle Layer ◽  
Unusual Complication ◽  
Internal Elastic Lamina ◽  
Content Type ◽  
Aneurysm Formation

✓ Intracranial aneurysms are an unusual complication of sickle-cell anemia; only 15 patients have been described in the world literature. An additional 15 patients with sickle-cell anemia and subarachnoid hemorrhage (SAH) from ruptured intracranial aneurysms are presented. There was a high incidence of multiple aneurysms (60%); some of which were in unusual locations. The clinical and pathological features of this series of patients have provided a paradigm for acquired aneurysm formation that may be applicable to other intracranial aneurysms. Thirteen patients underwent craniotomy and clip ligation; the perioperative management of these patients is discussed. Of these 13, eight had a good recovery, three were left with moderate disability, one patient died of surgical complications, and one died of complications related to sickle-cell anemia. Two of the 15 patients died of SAH. The authors propose that endothelial injury from the abnormal adherence of sickle erythrocytes to the endothelium is the initiating event in arterial wall injury. Subsequently, there is fragmentation of the internal elastic lamina and degeneration of the smooth-muscle layer. Hemodynamic stress at these loci of arterial wall damage results in aneurysm formation. This hypothesis also explains other cerebrovascular manifestations of sickle-cell anemia, namely vaso-occlusive disease and hemorrhage without aneurysm formation. Pathological material from this series and data from the literature are presented to support this hypothesis.

scholarly journals Development of an Intravascular Doppler Optical Coherence Tomography Imaging Technique for Neurovascular Applications

2021 ◽  
Author(s):  
Barry Vuong
Keyword(s):  
Blood Flow ◽  
Optical Coherence Tomography ◽  
Intracranial Aneurysm ◽  
Intracranial Aneurysms ◽  
Fluid Dynamic ◽  
Patient Specific ◽  
Optical Coherence ◽  
Specific Flow ◽  
Arterial Lumen ◽  
Risk Of Rupture

The rupture of an intracranial aneurysm can cause spontaneous subarachnoid hemorrhage and result in sudden death. A large portion of intracranial aneurysms occurs near the center of the head, at the skull base, which poses significant technical challenge to neurosurgeons due to limited accessibility. The utilization of angiography is prominent during the treatment of intracranial aneurysms. However, malapposition of stent or incomplete packing of the intracranial aneurysm can be difficult to assess with angiography, and could lead to severe postoperative complications. As a result, angiography may not be sufficient in determining the risk of rupture as the compensatory mechanisms are known to occur at the microstructural level due to the local hemodynamics in the arterial lumen, as well as in evaluating the intraoperative treatment. In this work, we describe a method for assessing intracranial aneurysm through the evaluation of blood flow within the lumen and morphological structures of the arterial wall with optical coherence tomography (OCT). Sterile intravascular fiber-optic catheters can be introduced in the artery to detect blood flow. Prior to this work, limited investigations of catheter based Doppler OCT (DOCT) were reported. A novel signal processing technique was developed to further reduce the effect of Doppler noise within a catheter based DOCT system. This technique consisted of splitting the interferogram of an OCT signal prior to estimating the Doppler shift. This split spectrum DOCT (ssDOCT) method was evaluated through flow models and porcine models, as well as through the correlation between ssDOCT algorithm and computational fluid dynamic (CFD) models. It was observed that ssDOCT provided improved Doppler artefact suppression over the conventional DOCT technique. ssDOCT also provided the ability to estimate lower velocities within the DOCT image to measure the hemodynamic patterns around stent struts in both the internal carotid and patient specific flow phantoms. An OCT imaging study was also conducted consisting of surgically resected human intracranial aneurysms. Further enhancement of the detection of these key morphological structures was demonstrated by an optical-attenuation imaging variant of OCT. The presented techniques could provide further insights to the cause of intracranial aneurysm rupture and vascular healing mechanisms.

scholarly journals Clinical relevance of short-term follow-up of unruptured intracranial aneurysms

2019 ◽  
Vol 47 (1) ◽  
pp. E7 ◽  
Author(s):  
Rob Molenberg ◽  
Marlien W. Aalbers ◽  
Jan D. M. Metzemaekers ◽  
Aryan Mazuri ◽  
Gert-Jan Luijckx ◽  
...  
Keyword(s):  
Clinical Relevance ◽  
Intracranial Aneurysms ◽  
Significant Risk ◽  
Patient Specific ◽  
Rupture Risk ◽  
Short Term ◽  
Unruptured Intracranial Aneurysms ◽  
Increased Risk ◽  
Risk Of Rupture

OBJECTIVEUnruptured intracranial aneurysms are common incidental findings on brain imaging. Short-term follow-up for conservatively treated aneurysms is routinely performed in most cerebrovascular centers, although its clinical relevance remains unclear. In this study, the authors assessed the extent of growth as well as the rupture risk during short-term follow-up of conservatively treated unruptured intracranial aneurysms. In addition, the influence of patient-specific and aneurysm-specific factors on growth and rupture risk was investigated.METHODSThe authors queried their prospective institutional neurovascular registry to identify patients with unruptured intracranial aneurysms and short-term follow-up imaging, defined as follow-up MRA and/or CTA within 3 months to 2 years after initial diagnosis. Medical records and questionnaires were used to acquire baseline information. The authors measured aneurysm size at baseline and at follow-up to detect growth. Rupture was defined as a CT scan–proven and/or CSF-proven subarachnoid hemorrhage (SAH).RESULTSA total of 206 consecutive patients with 267 conservatively managed unruptured aneurysms underwent short-term follow-up at the authors’ center. Seven aneurysms (2.6%) enlarged during a median follow-up duration of 1 year (range 0.3–2.0 years). One aneurysm (0.4%) ruptured 10 months after initial discovery. Statistically significant risk factors for growth or rupture were autosomal-dominant polycystic kidney disease (RR 8.3, 95% CI 2.0–34.7), aspect ratio > 1.6 or size ratio > 3 (RR 10.8, 95% CI 2.2–52.2), and initial size ≥ 7 mm (RR 10.7, 95% CI 2.7–42.8).CONCLUSIONSSignificant growth of unruptured intracranial aneurysms may occur in a small proportion of patients during short-term follow-up. As aneurysm growth is associated with an increased risk of rupture, the authors advocate that short-term follow-up is clinically relevant and has an important role in reducing the risk of a potential SAH.

Hemodynamic differences between unstable and stable unruptured aneurysms independent of size and location: a pilot study

2016 ◽  
Vol 9 (4) ◽  
pp. 376-380 ◽  
Author(s):  
Waleed Brinjikji ◽  
Bong Jae Chung ◽  
Carlos Jimenez ◽  
Christopher Putman ◽  
David F Kallmes ◽  
...  
Keyword(s):  
Shear Stress ◽  
Pilot Study ◽  
Wall Shear Stress ◽  
Intracranial Aneurysms ◽  
Wilcoxon Test ◽  
Patient Specific ◽  
Unruptured Aneurysms ◽  
Unruptured Intracranial Aneurysms ◽  
Wall Shear ◽  
Geometric Variables

BackgroundWhile clinical and angiographic risk factors for intracranial aneurysm instability are well established, it is reasonable to postulate that intra-aneurysmal hemodynamics also have a role in aneurysm instability.ObjectiveTo identify hemodynamic characteristics that differ between radiologically unstable and stable unruptured intracranial aneurysms.Materials and methods12 pairs of unruptured intracranial aneurysms with a 3D rotational angiographic set of images and followed up longitudinally without treatment were studied. Each pair consisted of one stable aneurysm (no change on serial imaging) and one unstable aneurysm (demonstrated growth of at least 1 mm diameter or ruptured during follow-up) of matching size (within 10%) and locations. Patient-specific computational fluid dynamics models were created and run under pulsatile flow conditions. Relevant hemodynamic and geometric variables were calculated and compared between groups using the paired Wilcoxon test.ResultsThe area of the aneurysm under low wall shear stress (low shear stress area (LSA)) was 2.26 times larger in unstable aneurysms than in stable aneurysms (p=0.0499). The mean aneurysm vorticity was smaller by a factor of 0.57 in unstable aneurysms compared with stable aneurysms (p=0.0499). No statistically significant differences in geometric variables or shape indices were found.ConclusionsThis pilot study suggests there may be hemodynamic differences between unstable and stable unruptured cerebral aneurysms. In particular, the area under low wall shear stress was larger in unstable aneurysms. These findings should be considered tentative until confirmed by future larger studies.

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