Hospital day 3 CT head without contrast: Diffuse subarachnoid blood products. There are also blood products layering within the occipital horns of the bilateral lateral ventricles. There are also subarachnoid blood products extending inferiorly surrounding the cervical cord. This is consistent with rupture of the patient's known basilar artery aneurysm. The ventricles are further enlarged with findings of transependymal CSF migration. There is no herniation.