Association of wall enhancement on high-resolution magnetic resonance imaging with morphology and hemodynamics in unruptured intracranial aneurysms.

Objective: To investigate the relationships between intracranial aneurysm (IA) wall enhancement (AWE) and aneurysm morphology and hemodynamic parameters.

Methods: A total of 100 patients (112 unruptured aneurysms) were categorized by enhancement degree (significant, slight, no enhancement) and pattern (circumferential, partial, no enhancement). Morphological and AWE features were measured using enhanced high-resolution magnetic resonance images (HR-MRI). Computational fluid dynamics (CFD) was used to calculate hemodynamic parameters, including time-averaged wall shear stress (TAWSS), normalized time-averaged wall shear stress (NTAWSS), oscillatory shear index (OSI), gradient oscillatory number (GON), and relative residence time (RRT).

Results: NTAWSS (p < 0.05), aspect ratio (AR, p < 0.01), and size ratio (SR, p < 0.01) showed significantly statistical difference among AWE groups. The significantly enhanced group had higher AR and SR and higher RRT but lower NTAWSS compared to non-enhanced and slightly enhanced groups. Enhancement ratio negatively correlated with NTAWSS (rs = -0.33, p < 0.001), OSI (rs = -0.28, p = 0.003), and positively correlated with the GON (rs = 0.22, p = 0.018) and RRT (rs = 0.31, p < 0.001) and SR (rs = 0.51, p < 0.001) and AR (rs = 0.48, p < 0.001).

Conclusion: Aneurysmal morphological and hemodynamic features are related to the degree and extent of AWE. Unruptured IAs with more intense AWE are larger and have lower NTAWSS and higher RRT.