Wall permeability on magnetic resonance imaging is associated with intracranial aneurysm symptoms and wall enhancement

Objectives Wall remodeling and inflammation accompany symptomatic unruptured intracranial aneurysms (UIAs). The volume transfer constant ( K trans ) of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) reflects UIA wall permeability. Aneurysmal wall enhancement (AWE) on vessel wall MRI (VWI) is associated with inflammation. We hypothesized that K trans is related to symptomatic UIAs and AWE. Methods Consecutive patients with UIAs were prospectively recruited for 3-T DCE-MRI and VWI from January 2018 to March 2023. UIAs were classified as asymptomatic and symptomatic if associated with sentinel headache or oculomotor nerve palsy. K trans and AWE were assessed on DCE-MRI and VWI, respectively. AWE was evaluated using the AWE pattern and wall enhancement index (WEI). Spearman’s correlation coefficient and univariate and multivariate analyses were used to assess correlations between parameters. Results We enrolled 82 patients with 100 UIAs (28 symptomatic and 72 asymptomatic). The median K trans (2.1 versus 0.4 min −1 ; p < 0.001) and WEI (1.5 versus 0.4; p < 0.001) were higher for symptomatic aneurysms than for asymptomatic aneurysms. K trans (odds ratio [OR]: 1.60, 95% confidence interval [95% CI]: 1.01–2.52; p = 0.04) and WEI (OR: 3.31, 95% CI: 1.05–10.42; p = 0.04) were independent risk factors for symptomatic aneurysms. K trans was positively correlated with WEI (Spearman’s coefficient of rank correlation (rs) = 0.41, p < 0.001). The combination of K trans and WEI achieved an area under the curve of 0.81 for differentiating symptomatic from asymptomatic aneurysms. Conclusions K trans may be correlated with symptomatic aneurysms and AWE. K trans and WEI may provide an additional value than the PHASES score for risk stratification of UIAs. Clinical relevance statement The volume transfer constant ( K trans ) from DCE-MRI perfusion is associated with symptomatic aneurysms and provides additional value above the clinical PHASES score for risk stratification of intracranial aneurysms. Key Points • The volume transfer constant is correlated with intracranial aneurysm symptoms and aneurysmal wall enhancement. • Dynamic contrast-enhanced and vessel wall MRI facilitates understanding of the pathophysiological characteristics of intracranial aneurysm walls. • The volume transfer constant and wall enhancement index perform better than the traditional PHASES score in differentiating symptomatic aneurysms.