Hemodynamic Characteristics Regarding Recanalization of Completely Coiled Aneurysms: Computational Fluid Dynamic Analysis Using Virtual Models Comparison

Abstract

PurposeHemodynamic factors are considered to play an important role in initiation and progression of the recurrence after endosaccular coiling of the intracranial aneurysms. We made paired virtual models of completely coiled aneurysms which were subsequently recanalized and compared to identify hemodynamic characteristics related to the recurred aneurysmal sac.Materials and MethodsWe created paired virtual models of computational fluid dynamics (CFD) in five aneurysms which were initially regarded as having achieved complete occlusion and then recurred during follow-up. Paired virtual models consisted of the CFD model of 3D rotational angiography obtained in the recurred aneurysm and the control model of the initial, parent artery after artificial removal of the coiled and recanalized aneurysm. Using the CFD analysis of the virtual model, we analyzed the hemodynamic characteristics on the neck of each aneurysm before and after its recurrence.ResultsHigh wall shear stress (WSS) was identified at the cross-sectionally identified aneurysm neck at which recurrence developed in all cases. A small vortex formation with relatively low velocity in front of the neck was also identified in four cases. The aneurysm recurrence locations corresponded to the location of high WSS and/or small vortex formation.ConclusionRecanalized aneurysms revealed increased WSS and small vortex formation at the cross-sectional neck of the aneurysm. This observation may partially explain the hemodynamic causes of future recanalization after coil embolization.

Microguidewire Looping to Traverse Stented Parent Arteries of Intracranial Aneurysms

“…Device improvements and advances in coiling techniques have now enabled treatment of lesions with complex configurations3,18). Stenting (and various modifications thereof) has contributed greatly in this context, broadening the scope of endovascular treatment substantially5,7,10,12,14–19,21).…”

Risk Factor Analysis of Recanalization Timing in Coiled Aneurysms: Early versus Late Recanalization

“…Hemodynamic force is another reputed factor in aneurysm recanalization and growth. 2 In recanalized aneurysms, maximum wall shear stress and spatially averaged wall shear stress exceed corresponding pretreatment values. 27 In addition, completely occluded aneurysms show diminished wall shear stress and flow velocity.…”

“…Risk factors linked to recanalization have been studied widely through comparative analysis, examining SAH at presentation, larger aneurysms, posterior locations, and other variables. 1,2 Coiled aneurysms showing major recanalization are subsequently in need of additional coiling, given the odds of rebleeding. Raymond et al 3 found that 46.9% of all recanalizations occurred within 6 months of procedures, with nearly 40% showing major recanalization.…”

Numerical simulation techniques to predict aneurysm recanalization after coil embolization and their problems

“…When applying the solid model, some studies reconstructed the coil mass using images taken by diagnostic imaging devices, other studies artificially reproduced the state in which the coil mass is deployed by reconstructing the cerebral artery geometries only at locations where there was blood flow or by artificially removing the aneurysm above the aneurysm neck surface from images before coil embolization. [6,8,11,12,16]. Ten reports have adopted this method.…”