Rupture risk of small intracranial aneurysm: comparison between small ruptured intracranial aneurysm and large unruptured intracranial aneurysm

Abstract

Abstract Background Size is one of the risk factors of intracranial aneurysms (IAs) rupture, but not a reliable marker of rupture risk. Two groups of IAs, ruptured IAs (RIAs) smaller than 5 mm and unruptured IAs (UIAs) larger than 10 mm, were compared to investigate the clinical and morphological characteristics associated with the risk factors for the rupture of small IAs. Methods The clinical data of 189 consecutive patients with 193 IAs were reviewed. The patients and IAs were divided into ruptured (smaller than 5 mm) and unruptured groups (larger than 10 mm). The characteristics of the patients and the IAs were compared between the two groups, and the rupture risk factors for small IAs were assessed using multiple logistic regression. Results Patient age (odds ratio [OR], 0.955), IA located at the internal carotid artery (OR, 0.202), irregular shape (OR, 0.083) and parent vessel diameter (OR, 0.426) were negatively correlated with a risk of small IA rupture. IAs located at bifurcations (OR, 6.766) were positively correlated with a risk of small IA rupture. Conclusions In addition to IA size, other factors, such as patient age, IA location, shape and parent vessel diameter, can influence the risk of small IA rupture.