LAUSR

BACKGROUND Compared with intracranial aneurysms (IAs) at other locations, pericallosal artery aneurysms (PAAs) demonstrate an extremely high risk of rupture. However, due to their rarity, our understanding of their morphological characteristics was limited, and whether the morphological characteristics of PAAs contributes to this high rupture risk remains unexplored. OBJECTIVE In this study, we aimed to provide a detailed description of the morphological characteristics of PAAs and investigate the association between its morphology and rupture risk by comparison with that of anterior circulation IAs at other locations. MATERIALS AND METHODS Forty patients with 45 PAAs and 348 patients with 392 anterior circulation IAs at other locations were recruited. The clinical and radiological data for these patients were retrospectively reviewed. The differences in morphologic parameters, including the aneurysm diameter (D), neck width (N), height (H), width (W), parent artery diameter (PA), inflow angle (IA), aspect ratio (AR), size ratio (SR) and aneurysm diameter/width (D/W) ratio, between PAAs and other IA groups were compared. RESULTS Twenty-two PAAs (48.9%) were ruptured, the proportion of ruptured aneurysms was highest in PAAs compared with IAs in the anterior circulation. For both ruptured and unruptured anterior circulation IAs, PAAs had the highest AR and SR among all IA groups. Furthermore, PAAs showed the largest inflow angle. CONCLUSION The morphological characteristics of PAAs are unique. Comparing with other anterior circulation IAs, PAAs are featured with significantly increased AR, SR and inflow angle which ultimately promote their high propensity of rupture.