Identification of Hostile Hemodynamics and Geometries of Cerebral Aneurysms: A Case-Control Study

Abstract

Unstable and ruptured aneurysms have more complex flows with concentrated wall shear stress and are larger, more elongated, and irregular than stable aneurysms, independent of aneurysm location and patient sex and age.

Assessing the Risk of Intracranial Aneurysm Rupture Using Morphological and Hemodynamic Biomarkers Evaluated from Magnetic Resonance Fluid Dynamics and Computational Fluid Dynamics

“…However, several studies have reported WSS in the aneurysm as a significant parameter in the rupture risk assessment. [23][24][25][26] In addition, ICI was unable to show a significant effect on the aneurysm rupture risk in the present study in contrast to the initial findings reported by Cebral et al 20 With respect to another two hemodynamic biomarkers, although we attempted the analysis of EL 21 and PLc, 22 confounding results were observed possibly due to the distinctive ways of approximation of static pressure variable by the fluid dynamic analysis software. Those results are not presented in this study as further scrutiny is warranted regarding the biomarker definitions and way of analysis.…”

“…The aspect ratio, presence of blebs and NSI did not gain statistical significance in our study comparable to Amigo and Valencia 26 but in contrast to several other studies. [17][18][19][23][24][25] In relation to the investigated hemodynamic biomarkers, OSI and RRT were significantly different between the ruptured group and the unruptured group of aneurysms suggesting higher blood oscillations and longer resident times near aneurysm wall can distinguish aneurysm rupture. The longer the time blood spends inside the aneurysm, the slower and circulatory its flow.…”

“…10 Shearing velocity is calculated by dividing velocity along the wall by distance from wall to the velocity measuring point. WSS related parameters evaluated in this study were time averaged wall shear stress (TAWSS), [23][24][25][26] oscillatory shear index (OSI) 27 and relative residence time (RRT). 28 TAWSS, OSI and RRT were further analyzed to obtain spatial average, spatial maximum and spatial minimum values.…”

“…16 Several recent studies have investigated morphological and hemodynamic parameters to assess the rupture risk of intracranial aneurysms and have found significant results with respect to aspect ratio, 17 size ratio, 18 presence of blebs, 5 nonsphericity index (NSI), 19 inflow concentration index, 20 energy loss, 21 pressure loss coefficient 22 and wall shear stress derivatives. [23][24][25][26][27][28] However, all of these studies are based on CFD analysis and none of these studies had used patient specific inflow-outflow boundary conditions for the analysis which is a major limitation. In addition, to our knowledge, no rigorous intracranial aneurysm rupture risk assessment study has been reported that utilizes MRFD analysis with representative larger samples rather than case reports.…”

External validation of cerebral aneurysm rupture probability model with data from two patient cohorts

“…Therefore, it gives the probability of being ruptured of a given aneurysm. However, based on the assumption that high risk aneurysms resemble those that have already ruptured [8], this model could also be useful for aneurysm rupture risk assessment. To evaluate the validity of the model for this application, the assessment of the model’s performance with longitudinal data is an essential next step and is planned for future work.…”