The Clinical and Morphologic Features Related to Aneurysm Wall Enhancement and Enhancement Pattern in Patients with Anterior Circulation Aneurysms

Abstract

Aneurysm wall enhancement (AWE) may predict rupture-prone intracranial aneurysms (IAs). However, the clinical and morphologic risk factors related to AWE have not been well described. Furthermore, the risk factors related to enhancement patterns have never been studied, especially in patients with anterior circulation aneurysms. Therefore, we aimed to investigate the risk factors related to wall enhancement and the enhancement patterns in anterior circulation unruptured aneurysms. One hundred patients (median age, 59 years; 68% female) with 113 anterior circulation unruptured aneurysms were included in this prospective study. Clinical and morphologic risk factors related to wall enhancement and circumferential enhancement were analyzed using univariate and multivariate analyses. There were 33 symptomatic unruptured IAs (29.2%) and 50 IAs with AWE (44.2%) (partial [n= 16] and circumferential [n= 34]). Univariate analysis showed that symptomatic IAs and morphologic factors (irregular shape, size, width, dome depth, size ratio, aspect ratio, and bottleneck) correlated with wall enhancement. Furthermore, female sex, blood parameters (cholesterol and low-density lipoprotein), and morphologic factors (size and dome depth) correlated with wall enhancement patterns (P<0.05). Multivariate analysis showed that size was the most important factor in wall enhancement (P= 0.06; odds ratio, 3.758) and a trend for symptomatic IAs (P= 0.033; odds ratio, 2.426). Female sex was the most important factor in circumferential enhancement (P= 0.017; odds ratio, 7.276). AWE was strongly associated with aneurysm size and was observed more frequently in symptomatic unruptured IAs. Sex hormones and atherosclerotic factors may be involved in circumferential enhancement. However, further studies should be performed to investigate the pathologic mechanisms for pattern of enhancement.