Hemodynamic characteristics of hyperplastic remodeling lesions in cerebral aneurysms

Abstract

Background & purposeHyperplastic remodeling (HR) lesions are sometimes found on cerebral aneurysm walls. Atherosclerosis is the results of HR, which may cause an adverse effect on surgical treatment for cerebral aneurysms. Previous studies have demonstrated that atherosclerotic changes had a correlation with certain hemodynamic characteristics. Therefore, we investigated local hemodynamic characteristics of HR lesions of cerebral aneurysms using computational fluid dynamics (CFD).MethodsTwenty-four cerebral aneurysms were investigated using CFD and intraoperative video recordings. HR lesions and red walls were confirmed on the intraoperative images, and the qualification points were determined on the center of the HR lesions and the red walls. The qualification points were set on the virtual operative images for evaluation of wall shear stress (WSS), normalized WSS (NWSS), oscillatory shear index (OSI), relative residence time (RRT), and aneurysm formation indicator (AFI). These hemodynamic parameters at the qualification points were compared between HR lesions and red walls.ResultsHR lesions had lower NWSS, lower AFI, higher OSI and prolonged RRT compared with red walls. From analysis of the receiver-operating characteristic curve for hemodynamic parameters, OSI was the most optimal hemodynamic parameter to predict HR lesions (area under the curve, 0.745; 95% confidence interval, 0.603–0.887; cutoff value, 0.00917; sensitivity, 0.643; specificity, 0.893; P<0.01). With multivariate logistic regression analyses using stepwise method, NWSS was significantly associated with the HR lesions.ConclusionsAlthough low NWSS was independently associated with HR lesions, OSI is the most valuable hemodynamic parameter to distinguish HR lesions from red walls.

Combining data from multiple sources to study mechanisms of aneurysm disease: Tools and techniques

“…These different appearances are thought to be indicative of local changes in the wall structure. For example, red regions correspond to thin translucent walls, while yellow and white regions are believed to correspond to “atherosclerotic” and “hyperplastic” remodeling regions, respectively . For comparison with local flow conditions and local biomechanical stresses, these regions of the wall are identified in intraoperative videos.…”

“…For example, red regions correspond to thin translucent walls, while yellow and white regions are believed to correspond to "atherosclerotic" and "hyperplastic" remodeling regions, respectively. 25,26 For comparison with local flow conditions and local biomechanical stresses, these regions of the wall are identified in intraoperative videos. In particular, the 3D vascular model reconstructed from the preoperative images is interactively marked using ChePen3D.…”

Effects of size and elasticity on the relation between flow velocity and wall shear stress in side-wall aneurysms: A lattice Boltzmann-based computer simulation study

“…In the present model, the input parameters are the surface elastic shear modulus κ s , the area dilation modulus κ α , and the bending modulus κ b . Both sets of parameters are related according to Eq (3) and Eq (4). For the sake of stability of simulations with a certain resolution, small values of Young's modulus E and transmural pressure P tr are utilized.…”

“…The interplay of hemodynamics and elastic arterial vessel walls (e.g. through wall shear stress (WSS) and blood pressure) is believed to play a central role in the aneurysm initiation, growth and rupture [3][4][5].…”

A Parameter to Identify Thin-walled Regions in Aneurysms by CFD

“…To avoid non-physical solution associated with the influence of inflow boundary conditions, a 0.15-m straight tube was connected to the inlet. 7) Computational and boundary conditions Blood flow was mathematically modeled as an incompressible Newtonian fluid with 1,056 kg/m 3 density and 0.0035 Pa•s viscosity 7) and was assumed to be laminar. Referring to preceding studies, unsteady calculation for two cardiac cycles was performed in each patient and the value at the second pulse peak was adopted.…”