What does computational fluid dynamics tell us about intracranial aneurysms? A meta-analysis and critical review.
Ontology highlight
ABSTRACT:
SUBMITTER: Saqr KM
PROVIDER: S-EPMC7181089 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Three-dimensional rotational angiography (3DRA) is an evolving imaging procedure from traditional digital subtraction angiography and is gaining much interest for detecting intracranial aneurysms. Computational fluid dynamics (CFD) modeling plays an important role in understanding the biomechanical properties and in facilitating the prediction of aneurysm rupture. A successful computational study relies on an accurate description of the vascular geometry that is obtained from volumetric images.The authors propose a new aneurysm segmentation algorithm to facilitate the study of CFD. This software combines a region-growing segmentation method with the 3D extension of a deformable contour based on a charged fluid model. A charged fluid model essentially consists of a set of charged elements that are governed by the nature of electrostatics. The approach requires no prior knowledge of anatomic structures and automatically segments the vasculature after the end-user selects a vessel section in a plane image.Experimental results on 15 cases indicate that aneurysm structures were effectively segmented and in good agreement with manual delineation outcomes. In comparison with the existing methods, the algorithm provided a much higher overlap index with respect to the ground truth. Furthermore, the outcomes of the proposed approach achieved a clean representation of vascular structures that is advantageous for hemodynamics analyses.A new aneurysm segmentation framework in an attempt to automatically segment vascular structures in 3DRA image volumes has been developed. The proposed algorithm demonstrated promising performance and unique characteristics to adequately segment aneurysms in 3DRA image volumes for further study in computational fluid dynamics.
| S-EPMC2789114 | biostudies-literature
Project description:OBJECTIVE: The importance of hemodynamics in the etiopathogenesis of intracranial aneurysms (IAs) is widely accepted. Computational fluid dynamics (CFD) is being used increasingly for hemodynamic predictions. However, alogn with the continuing development and validation of these tools, it is imperative to collect the opinion of the clinicians. METHODS: A workshop on CFD was conducted during the European Society of Minimally Invasive Neurological Therapy (ESMINT) Teaching Course, Lisbon, Portugal. 36 delegates, mostly clinicians, performed supervised CFD analysis for an IA, using the @neuFuse software developed within the European project @neurIST. Feedback on the workshop was collected and analyzed. The performance was assessed on a scale of 1 to 4 and, compared with experts' performance. RESULTS: Current dilemmas in the management of unruptured IAs remained the most important motivating factor to attend the workshop and majority of participants showed interest in participating in a multicentric trial. The participants achieved an average score of 2.52 (range 0-4) which was 63% (range 0-100%) of an expert user. CONCLUSIONS: Although participants showed a manifest interest in CFD, there was a clear lack of awareness concerning the role of hemodynamics in the etiopathogenesis of IAs and the use of CFD in this context. More efforts therefore are required to enhance understanding of the clinicians in the subject.
| S-EPMC2729101 | biostudies-literature
Project description:Background and purposeRupture risk assessment for intracranial aneurysms remains challenging, and risk factors, including wall shear stress, are discussed controversially. The primary purpose of the presented challenge was to determine how consistently aneurysm rupture status and rupture site could be identified on the basis of computational fluid dynamics.Materials and methodsTwo geometrically similar MCA aneurysms were selected, 1 ruptured, 1 unruptured. Participating computational fluid dynamics groups were blinded as to which case was ruptured. Participants were provided with digitally segmented lumen geometries and, for this phase of the challenge, were free to choose their own flow rates, blood rheologies, and so forth. Participants were asked to report which case had ruptured and the likely site of rupture. In parallel, lumen geometries were provided to a group of neurosurgeons for their predictions of rupture status and site.ResultsOf 26 participating computational fluid dynamics groups, 21 (81%) correctly identified the ruptured case. Although the known rupture site was associated with low and oscillatory wall shear stress, most groups identified other sites, some of which also experienced low and oscillatory shear. Of the 43 participating neurosurgeons, 39 (91%) identified the ruptured case. None correctly identified the rupture site.ConclusionsGeometric or hemodynamic considerations favor identification of rupture status; however, retrospective identification of the rupture site remains a challenge for both engineers and clinicians. A more precise understanding of the hemodynamic factors involved in aneurysm wall pathology is likely required for computational fluid dynamics to add value to current clinical decision-making regarding rupture risk.
| S-EPMC8013045 | biostudies-literature
Project description:Background and purposeCFD has been proved valuable for simulating blood flow in intracranial aneurysms, which may add to better rupture risk assessment. However, CFD has drawbacks such as the sensitivity to assumptions needed for the model, which may hinder its clinical implementation. 3D PC-MR imaging is a technique that enables measurements of blood flow. The purpose of this study was to compare flow patterns on the basis of 3D PC-MR imaging with CFD estimates.Materials and methods3D PC-MR imaging was performed in 8 intracranial aneurysms. Two sets of patient-specific inflow boundaries for CFD were obtained from a separate 2D PC-MR imaging sequence (2D CFD) and from the 3D PC-MR imaging (3D CFD) data. 3D PC-MR imaging and CFD were compared by calculation of the differences between velocity vector magnitudes and angles. Differences in flow patterns expressed as the presence and strengths of vortices were determined by calculation of singular flow energy.ResultsIn systole, flow features such as vortex patterns were similar. In diastole, 3D PC-MR imaging measurements appeared inconsistent due to low velocity-to-noise ratios. The relative difference in velocity magnitude was 67.6 ± 51.4% and 27.1 ± 24.9% in systole and 33.7 ± 21.5% and 17.7 ± 10.2% in diastole for 2D CFD and 3D CFD, respectively. For singular energy, this was reduced to 15.5 ± 13.9% at systole and 19.4 ± 17.6% at diastole (2D CFD).ConclusionsIn systole, good agreement between 3D PC-MR imaging and CFD on flow-pattern visualization and singular-energy calculation was found. In diastole, flow patterns of 3D PC-MR imaging differed from those obtained from CFD due to low velocity-to-noise ratios.
| S-EPMC7965648 | biostudies-literature
Project description:The objective of the study was to examine the correlations between intracranial aneurysm morphology and wall shear stress (WSS) to identify reliable predictors of rupture risk. Seventy-two intracranial aneurysms (41 ruptured and 31 unruptured) from 63 patients were studied retrospectively. All aneurysms were divided into two categories: narrow (aspect ratio ?1.4) and wide-necked (aspect ratio <1.4 or neck width ?4 mm). Computational fluid dynamics was used to determine the distribution of WSS, which was analyzed between different morphological groups and between ruptured and unruptured aneurysms. Sections of the walls of clipped aneurysms were stained with hematoxylin-eosin, observed under a microscope, and photographed. Ruptured aneurysms were statistically more likely to have a greater low WSS area ratio (LSAR) (P = 0.001) and higher aneurysms parent WSS ratio (P = 0.026) than unruptured aneurysms. Narrow-necked aneurysms were statistically more likely to have a larger LSAR (P < 0.001) and lower values of MWSS (P < 0.001), mean aneurysm-parent WSS ratio (P < 0.001), HWSS (P = 0.012), and the highest aneurysm-parent WSS ratio (P < 0.001) than wide-necked aneurysms. The aneurysm wall showed two different pathological changes associated with high or low WSS in wide-necked aneurysms. Aneurysm morphology could affect the distribution and magnitude of WSS on the basis of differences in blood flow. Both high and low WSS could contribute to focal wall damage and rupture through different mechanisms associated with each morphological type.
| S-EPMC5486504 | biostudies-literature
Project description:Background and purposePatient and aneurysm characteristics have been reported to differ between patients with familial and non-familial intracranial aneurysms (IAs), although results are inconsistent. We systematically reviewed and meta-analyzed the literature to identify and quantify patient- and aneurysm characteristics associated with familial IAs.MethodsWe searched PubMed and EMBASE for case-control and cohort studies comparing patient- and aneurysm characteristics between familial and non-familial IAs. Two observers independently assessed study eligibility and appraised quality with the Newcastle Ottawa Scale. With univariable weighted linear regression analysis we calculated β-coefficients with corresponding 95% confidence intervals (CIs) for ruptured and unruptured IAs combined and for ruptured IAs only. Heterogeneity was assessed with Higgins I2.ResultsA total of 15 articles were included in the meta-analysis in which 16,346 patients were analyzed with a total of 14,225 IAs. For ruptured and unruptured IAs combined, multiple IAs were more prevalent in familial (28.5%) than in non-familial IAs (20.4%; β = 0.10, 95% CI, 0.04 to 0.16; I2 0%). For ruptured IAs only, in familial patients IAs were more prevalent on the middle cerebral artery (41.1% versus 29.5%; β = 0.12, 95% CI, 0.01 to 0.24; I2 12%) and ruptured at a younger age (46.5 years versus 50.8 years; β = -5.00, 95% CI, -9.31 to -0.69; I2 98%) than in non-familial patients. No significant differences were found for the proportion of women, size of the aneurysm at time of rupture, smoking or hypertension.ConclusionThese results suggest that characteristics of familial and non-familial IAs show considerable overlap, yet differ on specific aspects. However, results for age at rupture showed considerable heterogeneity. These findings should be taken into consideration for future etiological research into IAs.
| S-EPMC6453525 | biostudies-literature
Project description:BackgroundThe safety and efficacy of treatment with self-expandable braided stents (LEO and LVIS) required further investigation.PurposeOur aim was to analyze the outcomes after treatment with braided stents.Data sourcesA systematic search of 3 databases was performed for studies published from 2006 to 2017.Study selectionAccording to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting patients treated with LEO or LVIS stents.Data analysisRandom-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, and neurologic outcomes.Data synthesisThirty-five studies evaluating 1426 patients treated with braided stents were included in this meta-analysis. Successful stent delivery and complete aneurysm occlusion were 97% (1041/1095; 95% CI, 95%-98%) (I2 = 44%) and 88.3% (1097/1256; 95% CI, 85%-91%) (I2 = 72%), respectively. Overall, treatment-related complications were 7.4% (107/1317; 95% CI, 5%-9%) (I2 = 44%). Ischemic/thromboembolic events (48/1324 = 2.4%; 95% CI, 1.5%-3.4%) (I2 = 27%) and in-stent thrombosis (35/1324 = 1.5%; 95% CI, 0.6%-1.7%) (I2 = 0%) were the most common complications. Treatment-related morbidity was 1.5% (30/1324; 95% CI, 0.9%-2%) and was comparable between the LEO and LVIS groups. Complication rates between the anterior (29/322 = 8.8%; 95% CI, 3.4%-12%) (I2 = 41%) versus posterior circulation (10/84 = 10.5%; 95% CI, 4%-16%) (I2 = 0%) and distal (30/303 = 8%; 95% CI, 4.5%-12%) (I2 = 48%) versus proximal aneurysms (14/153 = 9%; 95% CI, 3%-13%) (I2 = 46%) were comparable (P > .05).LimitationsLimitations were selection and publication biases.ConclusionsIn this analysis, treatment with the LEO and LVIS stents was relatively safe and effective. The most common complications were periprocedural thromboembolisms and in-stent thrombosis. The rate of complications was comparable among anterior and posterior circulation aneurysms, as well as for proximal and distally located lesions.
| S-EPMC7655354 | biostudies-literature
Project description:BackgroundThe implantation of flow-diverter stents for the treatment of ruptured intracranial aneurysms required further investigation.PurposeOur aim was to analyze the outcomes after flow diversion of ruptured intracranial aneurysms.Data sourcesA systematic search of 3 databases was performed for studies published from 2006 to 2018.Study selectionAccording to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies (from 2010 to 2018) reporting acutely ruptured intracranial aneurysms treated with flow diversion.Data analysisRandom-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, rebleeding, and factors influencing the studied outcomes.Data synthesisWe included 20 studies evaluating 223 patients with acutely ruptured intracranial aneurysms treated with flow-diverter stents. Immediate angiographic occlusion was obtained in 32% (29/86; 95% CI, 15.4%-48%; I2 = 79.6%) of aneurysms, whereas long-term complete/near-complete aneurysm occlusion was 88.9% (162/189; 95% CI, 84%-93.5%; I2 = 20.9%) (mean radiologic follow-up of 9.6 months). The treatment-related complication rate was 17.8% (42/223; 95% CI, 11%-24%; I2 = 52.6%). Complications were higher in the posterior circulation (16/72 = 27%; 95% CI, 14%-40%; I2 = 66% versus 18/149 = 11.7%; 95% CI, 7%-16%; I2 = 0%) (P = .004) and after treatment with multiple stents (14/52 = 26%; 95% CI, 14%-45%; I2 = 59%) compared with a single stent (20/141 = 10%; 95% CI, 5%-15%; I2 = 0%) (P = .004). Aneurysm rebleeding after treatment was 4% (5/223; 95% CI, 1.8%-7%; I2 = 0%) and was higher in the first 72 hours.LimitationsSmall and retrospective series.ConclusionsFlow-diversion treatment of ruptured intracranial aneurysms yields a high rate of long-term angiographic occlusion with a relatively low rate of aneurysm rebleeding. However, treatment is associated with a complication rate of 18%. When coiling or microsurgical clipping are not feasible strategies, anterior circulation ruptured aneurysms can be effectively treated with a flow-diversion technique, minimizing the number of stents deployed. Given the 27% rate of complications, flow diversion for ruptured posterior circulation aneurysms should be considered only in selected cases not amenable to other treatments.
| S-EPMC7655299 | biostudies-literature
Project description:BackgroundThe purpose of this analysis is to evaluate the current evidence with regard to the effectiveness and safety between coiling and clipping in patients with ruptured intracranial aneurysms (RIAs).MethodsWe performed a meta-analysis that compared clipping with coiling between July 2000 and September 2021. PubMed, EMBASE, and the Cochrane Library were searched for related articles systematically. And the treatment efficacy and postoperative complications were analyzed.ResultsWe identified three randomized controlled trials and thirty-seven observational studies involving 60,875 patients with ruptured cerebral aneurysms. The summary results showed that coiling was related a better quality of life (mRS0-2; OR=1.327; CI=1.093-1.612; p<0.05), a higher risk of mortality (OR=1.116; CI=1.054-1.180; p<0.05), higher rate of rebleeding (RR=1.410; CI=1.092-1.822; p<0.05), lower incidence of vasospasm (OR=0.787; CI=0.649-0.954; p<0.05), higher risk of hydrocephalous (RR=1.143; CI=1.043-1.252; p<0.05), lower risk of cerebral infarction (RR=0.669; CI=0.596-0.751; p<0.05), lower risk of neuro deficits (RR=0.720; CI=0.582-0.892; p<0.05), and a lower rate of complete occlusion (OR=0.495; CI=0.280-0.876; p<0.05).ConclusionCoiling was significantly associated with a better life quality (mRS0-2), a lower incidence of postoperative complications, and a higher rate of mortality, rebleeding, hydrocephalous, and a lower rate of complete occlusion than clipping.
| S-EPMC9310462 | biostudies-literature
Project description:Background and purposeThe Woven EndoBridge is an intrasaccular device for the treatment of intracranial aneurysms. The first generation consisted of a high-profile double-layer braid. This review aims to evaluate the outcomes of the new generation low-profile Woven EndoBridge single layer device for intracranial aneurysm treatment.MethodsA systematic review was conducted with Medline, Embase, and Web of Science Conference Proceedings databases. The search strategy provided 589 articles, 15 articles were included.ResultsFifteen articles were identified reporting the use of Woven EndoBridge single-layer devices in 963 aneurysms, mostly wide-necked bifurcation aneurysms. Procedural aneurysm rupture was reported in 8 of 963 patients (0.83%; 95%CI 0.39-1.66%) and thromboembolic events in 54 of 963 patients (5.61%, 95CI 4.31-7.26%). Cumulative morbidity was 2.85% (27/949, 95%CI 1.95-4.12%) and mortality 0.93% (9/963, 95%CI 0.46-1.80%). The overall rate of adequate aneurysm occlusion at last follow-up was 83.3% (613/736; 95%CI 80.4-85.8%). Retreatment was reported in 38 aneurysms in eight studies with 450 aneurysms with follow-up (38/450; 8.4%, 95CI 6.2-11.4%). In 12 studies comprising 644 aneurysms with follow-up, rebleeds occurred in three patients in three studies with mean follow-up between 3.3 and 14.4 months (0.47%, 95%CI 0.09-1.43%).ConclusionWoven EndoBridge single-layer is a promising new low-profile device especially for wide-neck bifurcation aneurysms, both ruptured and unruptured. No antiplatelet medication is needed which is a great advantage, especially in ruptured aneurysms. Efficacy and safety compare favorably with (stent-assisted) coiling. However, no direct comparison with other treatments is available as yet.
| S-EPMC7446584 | biostudies-literature