Can Endovascular Treatment of Fusiform Intracranial Aneurysms Restore the Healthy Hemodynamic Environment?-A Virtual Pilot Study.

Sylvia Saalfeld,Philipp Berg,Janneck Stahl,Yurii Cherednychenko,Laurel Morgan Miller Marsh,Jana Korte,Daniel Behme,Oliver Beuing,Bernhard Preim

doi:10.3389/fneur.2021.771694

Abstract

Numerous studies assess intracranial aneurysm rupture risk based on morphological and hemodynamic parameter analysis in addition to clinical information such as aneurysm localization, age, and sex. However, intracranial aneurysms mostly occur with a saccular shape located either lateral to the parent artery or at a bifurcation. In contrast, fusiform intracranial aneurysms (FIAs), i.e., aneurysms with a non-saccular, dilated form, occur in approximately 3–13% of all cases and therefore have not yet been as thoroughly studied. To improve the understanding of FIA hemodynamics, this pilot study contains morphological analyses and image-based blood flow simulations in three patient-specific cases. For a precise and realistic comparison to the pre-pathological state, each dilation was manually removed and the time-dependent blood flow simulations were repeated. Additionally, a validated fast virtual stenting approach was applied to evaluate the effect of virtual endovascular flow-diverter deployment focusing on relevant hemodynamic quantities. For two of the three patients, post-interventional information was available and included in the analysis. The results of this numerical pilot study indicate that complex flow structures, i.e., helical flow phenomena and the presence of high oscillating flow features, predominantly occur in FIAs with morphologically differing appearances. Due to the investigation of the individual healthy states, the original flow environment could be restored which serves as a reference for the virtual treatment target. It was shown that the realistic deployment led to a considerable stabilization of the individual hemodynamics in all cases. Furthermore, a quantification of the stent-induced therapy effect became feasible for the treating physician. The results of the morphological and hemodynamic analyses in this pilot study show that virtual stenting can be used in FIAs to quantify the effect of the planned endovascular treatment.

Highlights

Fusiform intracranial aneurysms (FIAs) are circumferential dilatations of the cerebral vessels leading to pathological hemodynamics
For each fusiform intracranial aneurysms (FIAs) case, the maximum cross-sectional area is evaluated. This is followed by an analysis of the hemodynamic parameters, including a comparison with the manually-created healthy counterparts, and the post-interventional states based on the virtual deployment
The blood flow pattern for the FIA shows a small vortex in the aneurysmal lumen indicating a complex flow structure

Summary

Introduction

Fusiform intracranial aneurysms (FIAs) are circumferential dilatations of the cerebral vessels leading to pathological hemodynamics. FIAs more often occur at the posterior cerebral circulation, can strongly vary in size (diameter and length), and are more often present in young patients with a higher prevalence in men when compared to saccular IAs which have a 3-fold larger prevalence in women [5]. Due to their rarity, FIAs have not been as well studied as saccular aneurysms including morphological and hemodynamic parameter analysis with respect to rupture risk. The individual hemodynamic state is difficult to assess, since a clear distinction between the aneurysmal lumen and the parent vessel can be highly complicated

Methods

Results

Discussion

Conclusion