Digital subtraction angiography (DSA) images were compared between patients with BBAs (n = 12, group A) and patients with unruptured paraclinoid aneurysms ≤ 5 mm in size treated by endovascular procedures (n = 12, group B). DSA images were assessed for irregularities in the diameter of the parent artery and delayed inflow and outflow of contrast medium in the aneurysm. Enlargement of the aneurysm and morphological changes from the first assessment were also evaluated in patients with BBAs. Compared to the group B, group A had a higher proportion of irregular vessel diameter (p = 0.013) and the delayed contrast medium outflow (p = 0.014). As well, stagnation of contrast medium along the aneurysm wall was a characteristic finding of BBAs, even for small aneurysms. Irregular morphological features of the parent artery and delayed contrast medium outflow as characteristic findings of ruptured BBAs may improve the diagnosis of these uncommon aneurysms, which remains challenging in practice. This was a retrospective analysis of patients with an aneurysm diagnosed as a BBA treated at our hospital or its affiliated institutions between 2008 and 2020. BBAs were comprehensively diagnosed by an expert neuro-interventionalist based on the following characteristics: ruptured and small aneurysm, non-bifurcated site of the ICA, aneurysm enlargement over time, irregular vessel wall, and young age. Previous studies have largely focused on the treatment strategies for BBAs, with little emphasis on the characteristic imaging of BBAs. In this study, we investigated the morphological and contrast medium dynamic characteristics of ruptured BBAs diagnosed from the clinical course and initial imaging, based on DSA. Our findings indicate that irregularity of the parent artery and delayed outflow of contrast medium in the aneurysm were significant imaging findings for BBAs.

With Regards,
Sara Giselle
Associate Managing Editor
Journal of Stroke Resarch & Therapy