Non-contrast enhanced silent MR angiography to evaluate hemodynamics and morphology of unruptured intracranial aneurysms: a comparative computational fluid dynamics study

Abstract

BackgroundSilent MR angiography (silent MRA) is a new generation of non-contrast enhanced angiography with outstanding advantages in visualizing cerebrovascular lesions and the follow-up after endovascular treatment for intracranial aneurysms (IAs). This study aims to investigate the reliability of silent MRA-based three-dimensional (3D) geometric description and hemodynamic calculation of IAs.Methods19 patients with 23 unruptured IAs, who underwent both silent MRA and 3D rotational angiography (3DRA), were included in this study. Computational fluid dynamics simulations were performed on all patient-specific 3D reconstruction images to compare the morphology and hemodynamics of the two different imaging models for IAs.ResultsSilent MRA models had smaller maximum and perpendicular height (mm), aneurysmal surface area (mm2), and aneurysmal volume (mm3) than 3DRA (p<0.05); the differences of the above parameters between the two models were 9.0±6.2%, 7.7±7.4%, 15.9±13.0%, and 21.4±17.5%, respectively. However, correlation analysis of morphological parameters in various dimensions and model comparison showed good overall consistency in geometrical characteristics between the two models. Moderate coherence was observed between models in time-averaged wall shear stress of aneurysm and parent vessel (TAWSS, PAWSS), aneurysm velocity (AV), parent vessel velocity, and oscillatory shear index (OSI). However, strong correlations were observed among normalized aneurysm wall shear stress (NWSS), low shear area (LSA), inflow concentration index (ICI), and normalized aneurysm velocity (NAV).ConclusionBoth morphological and hemodynamic assessments of IAs for silent MRA are comparable to 3DRA. Additionally, normalized indicators such as NWSS, LSA, ICI, and NAV were better than TAWSS, AV, and OSI in silent MRA-related hemodynamic evaluation.

Nomograms for assessing the rupture risk of anterior choroid artery aneurysms based on clinical, morphological, and hemodynamic features

“…The procedure using MIMICS 21.0 software (Materialise NV, Leuven, Belgium) unfolds as follows: Data are imported via “New Project,” settings are adjusted through “Threshold” until blood vessels are distinctly displayed, the region of interest is selected in “Crop Mask” for 3D image reconstruction, and the resultant file is exported in STereoLithography (STL) format. AneuFlow™ software (V1.1.4.1, ArteryFlow Technology, Hangzhou, China) for measuring aneurysm morphology and hemodynamics encompasses three steps ( 18 ). First, the STL file is imported into the AneuFlow™ software, allowing doctors to obtain additional morphological parameters by manually identifying the aneurysm neck.…”

Assessing the risk of intracranial aneurysm rupture using computational fluid dynamics: a pilot study

“…Briefly, DICOM images were segmented in the region of interest, including aneurysm sac and adjacent parent vessels. Then eight morphological parameters ( 20 , 21 ) were measured and calculated using AneuFlowTM (ArteryFlow, Hangzhou) ( 22 ), including H max , SR, AR, θ F , θ A , EI, NSI, UI. As for CFD models, finite volume meshes with 0.5–1 million elements were imported into the CFD solver to calculate time-resolved 3D velocity and pressure fields.…”