Correlation between computational fluid dynamics-derived low wall shear stress and vessel wall enhancement on high-resolution MR vessel wall imaging in intracranial aneurysms.

objectiveTo determine whether regions of low wall shear stress (WSS) derived from computational fluid dynamics (CFD) spatially correspond to vessel wall imaging (VWI) enhancement in unruptured intracranial aneurysms. MATERIALS AND

methodsWe retrospectively analyzed 49 patients with 49 unruptured intracranial aneurysms who underwent contrast-enhanced high-resolution VWI and angiographic imaging. A board-certified neuroradiologist identified the epicenter of maximal aneurysm wall enhancement on VWI. Patient-specific aneurysm lumens were reconstructed for CFD to map WSS on the aneurysm surface, and low-WSS locations were extracted on the sac. Spatial correspondence was quantified as the three-dimensional Euclidean distance between the VWI-enhancing focus and the nearest low-WSS location. A reference threshold of 1.42 mm (diagonal length of the acquisition voxel) was used to categorize close versus loose proximity. Associations between distance and aneurysm size/location were evaluated using Spearman correlation and the Kruskal-Wallis test.

resultsThe median distance between the VWI-enhancing focus and the low-WSS location was 0.55 mm (interquartile range: 0.33-1.39 mm). Using the 1.42-mm reference threshold, 37 of 49 aneurysms (75.5%) demonstrated proximity within this range. No significant associations were found between WSS-VWI proximity and aneurysm size (Spearman's rho = 0.243, p = 0.093) or location (p = 0.667).

conclusionsLow-WSS locations on CFD correspond to inflammatory enhancement on VWI, supporting the concept that low shear stress is associated with aneurysm wall inflammation. CFD-based hemodynamic analysis may serve as a noninvasive method for predicting vessel wall inflammation and assessing aneurysm instability. KEY POINTS: Question Detecting vessel wall inflammation in intracranial aneurysms requires specialized contrast MRI. Can CFD identify inflammatory regions noninvasively through low WSS mapping? Findings Low WSS regions from CFD closely corresponded to inflammatory enhancement on high-resolution MR VWI, showing submillimeter spatial agreement. Clinical relevance CFD-derived WSS mapping provides a noninvasive method to predict aneurysm wall inflammation and instability, potentially enabling earlier risk stratification and reducing the need for contrast-enhanced MRI in routine aneurysm surveillance and treatment decision-making.