RT Journal Article
SR Electronic
T1 Does Arterial Flow Rate Affect the Assessment of Flow-Diverter Stent Performance?
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
DO 10.3174/ajnr.A4933
A1 H.G. Morales
A1 O. Bonnefous
A1 A.J. Geers
A1 O. Brina
A1 V.M. Pereira
A1 L. Spelle
A1 J. Moret
A1 I. Larrabide
YR 2016
UL http://www.ajnr.org/content/early/2016/09/15/ajnr.A4933.abstract
AB BACKGROUND AND PURPOSE: Our aim was to assess the performance of flow-diverter stents. The pre- and end-of-treatment angiographies are commonly compared. However, the arterial flow rate may change between acquisitions; therefore, a better understanding of its influence on the local intra-aneurysmal hemodynamics before and after flow-diverter stent use is required.MATERIALS AND METHODS: Twenty-five image-based aneurysm models extracted from 3D rotational angiograms were conditioned for computational fluid dynamics simulations. Pulsatile simulations were performed at different arterial flow rates, covering a wide possible range of physiologic flows among 1–5 mL/s. The effect of flow-diverter stents on intra-aneurysmal hemodynamics was numerically simulated with a porous medium model. Spatiotemporal-averaged intra-aneurysmal flow velocity and flow rate were calculated for each case to quantify the hemodynamics after treatment. The short-term flow-diverter stent performance was characterized by the relative velocity reduction inside the aneurysm.RESULTS: Spatiotemporal-averaged intra-aneurysmal flow velocity before and after flow-diverter stent use is linearly proportional to the mean arterial flow rate (minimum R2 > 0.983 of the linear regression models for untreated and stented models). Relative velocity reduction asymptotically decreases with increasing mean arterial flow rate. When the most probable range of arterial flow rate was considered (3–5 mL/s), instead of the wide possible flow range, the mean SD of relative velocity reduction was reduced from 3.6% to 0.48%.CONCLUSIONS: Both intra-aneurysmal aneurysm velocity and flow-diverter stent performance depend on the arterial flow rate. The performance could be considered independent of the arterial flow rates within the most probable range of physiologic flows.AbbreviationsCFDcomputational fluid dynamicsmratio between the aneurysm velocity and the arterial flowQ̅mean arterial flow rateQminminimum arterial flow rate required to have a distinguishable velocity inside the aneurysmsstenteduuntreated;v̅e̅l̅redrelative velocity reductionvelsaspatiotemporal-averaged flow velocity