Evaluation of the shrinkage process of a neck remnant after stent-coil treatment of a cerebral aneurysm using silent magnetic resonance angiography and computational fluid dynamics analysis: illustrative case

J Neurosurg Case Lessons. 2024 Apr 15;7(16):CASE24141. doi: 10.3171/CASE24141. Print 2024 Apr 15.


Background: Silent magnetic resonance angiography (MRA) mitigates metal artifacts, facilitating clear visualization of neck remnants after stent and coil embolization of cerebral aneurysms. This study aims to scrutinize hemodynamics at the neck remnant by employing silent MRA and computational fluid dynamics.

Observations: The authors longitudinally tracked images of a partially thrombosed anterior communicating artery aneurysm's neck remnant, which had been treated with stent-assisted coil embolization, using silent MRA over a decade. Computational fluid dynamics delineated the neck remnant's reduction process, evaluating hemodynamic parameters such as flow rate, wall shear stress magnitude and vector, and streamlines. The neck remnant exhibited diminishing surface area, volume, neck size, dome depth, and aspect ratio. Its reduction correlated with a decline in the flow rate ratio of the remnant dome to the inflow parent artery. Analysis delineated regions within the contracting neck remnant characterized by consistently low average wall shear stress magnitude and variation, accompanied by notable variations in wall shear stress vector directionality.

Lessons: Evaluation of neck remnants after stent-coil embolization is possible through silent MRA and computational fluid dynamics. Predicting the neck remnant reduction may be achievable through hemodynamic parameter analysis.

Keywords: computational fluid dynamics; magnetic resonance image; neck remnant; silent magnetic resonance angiography; stent and coil embolization; wall shear stress.