Presentation
Severe headache. Right trochlear nerve palsy.
Patient Data
Non-contrast CT demonstrates minimal subarachnoid hemorrhage in the prepontine and interpeduncular cisterns. Mild/moderate hydrocephalus.
On CTA, the right superior cerebellar artery shows small saccular aneurysm at its origin. It measures 2mm in max transverse diameter. It has a narrow neck and its fundus is projecting laterally. No evidence of contrast extravasation.The distal portion of the artery isn't visualized (likely spastic).
Compare with the normal contralateral left superior cerebellar artery.
Hypoplastic right P1 segment with continuation of the right PCOM artery (normal variant).
The right superior cerebellar artery shows small saccular aneurysm at its origin (Yellow and blue arrows)
Non contrast CT axial cuts of the brain revealed minimal subarachnoid hemorrhgae at the prepontine and interpeduncular cisterns (Red arrows on the axial non contrast CT cuts)
On the post contrast axial arterial phase shows small saccular aneurysm projecting from the right superior cerebellar artery (Blue arrow)
Case Discussion
Superior cerebellar arteries (SCA) are rare and account for 1.7% of all the intracranial aneurysms. 1
Most patients with superior cerebellar artery aneurysm present with SAH. Since the SCA is closely related to cranial nerves III, IV and V, some aneurysms present with palsies of these nerves.