Non-contrast head CT (A) showing diffuse subarachnoid hemorrhage and hydrocephalus. Non-contrast head CT (A) showing diffuse subarachnoid hemorrhage and hydrocephalus. Anteroposterior (B) and lateral (C) imaging of a ruptured basilar apex aneurysm found in this patient measuring 3.3 mm in height and 4.7 mm in neck size before treatment. The same basilar apex on follow-up imaging—anteroposterior (D) and lateral (E)—at 1 year, showing incomplete occlusion. Adam S Arthur et al. J NeuroIntervent Surg doi:10.1136/neurintsurg-2019-014815 Copyright © Society of NeuroInterventional Surgery. All rights reserved.