Morphological Parameters Related to Aneurysm Wall Enhancement in Patients with Multiple Intracranial Aneurysms

Background: Vessel wall magnetic resonance imaging (MRI) has been suggested as a potential in vivo method to detect inflammation of aneurysm wall and identify unruptured intracranial aneurysm (UIA) at high risk for rupture. This study aims to investigate the correlation between aneurysm wall enhancement (AWE) on vessel wall MRI and rupture-related morphological parameters in patients with multiple UIAs.

Methods: Clinical data and vessel wall MRI images were reviewed in 14 patients with 30 multiple UIAs. The AWE was defined as enhancement of the aneurysm wall in postcontrast vessel wall MRI using the precontrast MRI as a reference. Morphological parameters, including aneurysm size, aspect ratio, size ratio, bottleneck factor, height-to-width ratio, nonsphericity index (NSI), and inflow angle, were measured using 3-dimensional rotation angiography. Univariate and multivariate analyses were performed to evaluate the correlations between morphological parameters and the presence of AWE.

Results: Sixteen of the 30 multiple UIAs presented with AWE on vessel wall MRI. On univariate analyses, UIAs with AWE were significantly larger (P = 0.001) and had significantly higher aspect ratio (P = 0.047), size ratio (P = 0.003), bottleneck factor (P = 0.007), and NSI (P = 0.007) values. Further multivariate logistic regression showed that aneurysm size (odds ratio, 3.54; 95% confidence interval, 1.10-11.35; P = 0.033) and NSI (odds ratio, 3.53; 95% confidence interval, 1.06-11.80; P = 0.040) were independently associated with the presence of AWE in multiple UIAs.

Conclusions: The presence of AWE on vessel wall MRI was significantly correlated with conventional morphological rupture risk factors in patients with multiple UIAs, which might indicate AWE as a potential radiologic predictor for UIAs with high rupture risk.