Association between aneurysm hemodynamics and wall enhancement on 3D vessel wall MRI

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Aneurysm wall enhancement (AWE) on 3D vessel wall MRI (VWMRI) has been suggested as an imaging biomarker for intracranial aneurysms (IAs) at higher risk of rupture. While computational fluid dynamics (CFD) studies have been used to investigate the association between hemodynamic forces and rupture status of IAs, the role of hemodynamic forces in unruptured IAs with AWE is poorly understood. The authors investigated the role and implications of abnormal hemodynamics related to aneurysm pathophysiology in patients with AWE in unruptured IAs.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Twenty-five patients who had undergone digital subtraction angiography (DSA) and VWMRI studies from September 2016 to September 2017 were included, resulting in 22 patients with 25 IAs, 9 with and 16 without AWE. High-resolution CFD models of hemodynamics were created from DSA images. Univariate and multivariate analyses were performed to investigate the association between AWE and conventional morphological and hemodynamic parameters. Normalized MRI signal intensity was quantified and quantitatively associated with wall shear stresses (WSSs) for the entire aneurysm sac, and in regions of low, intermediate, and high WSS.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>The AWE group had lower WSS (p &lt; 0.01) and sac-averaged velocity (p &lt; 0.01) and larger aneurysm size (p &lt; 0.001) and size ratio (p = 0.0251) than the non-AWE group. From multivariate analysis of both hemodynamic and morphological factors, only low WSS was found to be independently associated with AWE. Sac-averaged normalized MRI signal intensity correlated with WSS and was significantly different in regions of low WSS compared to regions of intermediate (p = 0.018) and high (p &lt; 0.001) WSS.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>The presence of AWE was associated with morphological and hemodynamic factors related to rupture risk. Low WSS was found to be an independent predictor of AWE. Our findings support the hypothesis that low WSS in IAs with AWE may indicate a growth and remodeling process that may predispose such aneurysms to rupture; however, a causality between the two cannot be established.</jats:p></jats:sec>

Multimodal validation of focal enhancement in intracranial aneurysms as a surrogate marker for aneurysm instability

“…In this study, focal enhancement was colocalized with low AWSS, low maxOSI, and high LSA in agreement with results recently published by Xiao et al and Khan et al [13,31], confirming the assumption that enhanced regions possibly indicate the presence and localization of low-flow conditions in an aneurysm.…”

Spatial Configuration of Abdominal Aortic Aneurysm Analysis as a Useful Tool for the Estimation of Stent-Graft Migration

“…AAA is a high-risk vascular disease which treatment depends on its diameter. When the diameter is lower than 40 mm pharmacological treatment is applied [ 2 , 3 ], while AAA with diameter equal or above 55 mm and growth rate over 5 mm every 6 months require surgical repair either open or endovascular [ 4 ].…”

Regional Aneurysm Wall Enhancement is Affected by Local Hemodynamics: A 7T MRI Study

“…19 Similarly, another study found that aneurysms with AWE were larger and had lower WSS and velocities than aneurysms without enhancement, and the AWE signal intensity was inversely correlated with WSS magnitude. 20 A recent study showed that the presence of AWE was associated with low normalized WSS, size, and size ratio. 21 However, several factors other than inflammation have been proposed as potential causes of increased AWE signals, in particular low-flow patterns that lead to pseudoenhancement signals in vivo.…”