Sidewall Aneurysm Geometry as a Predictor of Rupture Risk Due to Associated Abnormal Hemodynamics

Abstract

Background: Hemodynamics play an important role in intracranial aneurysm (IA) initiation, growth, and rupture. Yet there remains no definitive quantitative analysis between abnormal hemodynamics and geometrical risk of IA development. Objective: The present study aims to investigate whether abnormal hemodynamics in IA sacs can be predicted by surrogate geometric markers. Methods: Computational fluid dynamics (CFD) simulations were performed on paraclinoid aneurysms derived from digital subtraction angiography (DSA) of 104 IAs in 104 patients. Four basic IA geometric parameters including maximum height, perpendicular height, maximum width, and neck diameter were measured. Abnormal hemodynamics were defined and quantified as the surface area exposed to low wall shear stress (WSS) and high oscillatory shear index (OSI) using objectively-defined thresholds. Relationships between abnormal hemodynamics and specific geometric parameters were analyzed via multiple linear regression. Results: Adjusting for age, sex, and other clinical characteristics, multiple linear regression revealed a significant relationship ( p < 0.001) between abnormal hemodynamics and both maximum width (β ≈ 1.2) and neck diameter (β ≈ −0.4), but not maximum height or perpendicular height. These findings were shown to be independent of the choice of abnormal hemodynamic indicators and threshold levels. Conclusions: Maximum width and neck diameter of IA sacs are robust surrogates of exposure to abnormal hemodynamics. Risk of rupture may be increased with wider aneurysms with narrower necks for paraclinoid aneurysms.

The effect of Dean, Reynolds and Womersley numbers on the flow in a spherical cavity on a curved round pipe. Part 1. Fluid mechanics in the cavity as a canonical flow representing intracranial aneurysms

“…Understanding the fluid dynamics at the neck and inside the sac of intracranial aneurysms, and its dependence on anatomical and physiological parameters that change from case to case, is essential to quantify the changes in haemodynamics introduced by endovascular treatment, and in particular by flow diverting stents (Fukuda et al 2019;Texakalidis et al 2019;Wan et al 2019). Flow patterns such as strong inflow jets in the aneurysmal sac have been found to be detrimental to treatment with flow diverters (Chen et al 2019;Su et al 2020), whose goal is the formation of a stable thrombus for successful treatment (Rajah, Narayanan & Rangel-Castilla 2017).…”

“…2019; Wan et al. 2019). Flow patterns such as strong inflow jets in the aneurysmal sac have been found to be detrimental to treatment with flow diverters (Chen et al.…”

Analysis of the wall thickness of intracranial aneurysms: Can computational fluid dynamics detect the translucent areas of saccular intracranial aneurysms and predict the rupture risk preoperatively?

“…When the statistical analysis was carried out again with the exclusion of the outliers (No. 15,17,31,34,45), the results were the same (Z = 1.664, P = 0.008). There were no significant differences in the multiple (I s ) area increases between the ruptured and unruptured aneurysms (Z = 0.756, P = 0.617).…”

“…When the statistical analysis was carried out again with the exclusion of the outliers (No. 15,17,31,34,45), the results revealed no significant difference between the two groups (Z = 0.985, P = 0.287). In the patients with unruptured aneurysms, the difference was statistically significant in the volume of aneurysms between the translucent group (Group B) and nontranslucent group (Group C) (z = 1.645, P = 0.009).…”

VICTORIA: VIrtual neck Curve and True Ostium Reconstruction of Intracranial Aneurysms

“…Although the multidisciplinary research effort related to rupture risk assessment and treatment support of IAs drastically increased over the last years and specific knowledge about morphological and hemodynamic phenomena could be obtained, a successful translation of these findings into a clinical environment is still lacking. 13 , 34 , 38 The underlying reasons are manifold: First, only commercially available software tools can be used. Second, the medical community is rather conservative and (potential) improvements need to be evaluated carefully.…”