Presentation
CT scan performed as an outpatient for an indication of headache.
Patient Data
Round high attenuation lesion in prepontine region.
Normal appearances of the brain parenchyma.
6 mm rounded signal void (PD) in the ventral to the pons just left of the midline, in keeping with a basilar tip aneurysm.
Case Discussion
Basilar tip aneurysm. One form of posterior circulation cerebral aneurysm which account for only the minority of aneurysms with 90% occurring in the anterior circulation.
Cerebral aneurysms typically occur close to bifurcations, as with this one, which has the posterior cerebral artery immediately posteriorly.