Clinicopathological Insights From Vessel Wall Imaging of Unruptured Intracranial Aneurysms

Background and Purpose— The clinical significance of vessel wall imaging (VWI) remains unclear in patients with unruptured intracranial aneurysms. This study was performed to investigate the correlations between aneurysm wall imaging findings and histopathologic aneurysm wall architectures. Methods— A total of 9 aneurysms was evaluated by VWI and subsequently characterized with histopathology. We used VWI to visualize the aneurysm wall and determine if there was aneurysm wall enhancement after gadolinium contrast administration. Results— Aneurysm wall structures were identified in 6 of 9 unruptured intracranial aneurysms by native VWI, and wall enhancement was identified in 5 of these 6 aneurysms. Histopathologic studies revealed that wall thickening accompanied by atherosclerosis, neovascularization, and macrophage infiltration corresponded to visualization of the aneurysm wall by native VWI and to aneurysm wall enhancement. Conclusions— VWI can visualize thickening of the aneurysm wall, and wall enhancement corresponded to histologically confirmed degenerative changes accompanied by neovascularization and prominent macrophage infiltration.