Basilar Tip Aneurysm with spasm

Ray Ballinger, MD, PhD

Straub Clinic and Hospital

rballinger at


41 y/o woman with sudden onset of headache


brain aneurysm CT

Publication Date: 13 October 2003

History and Images

41 y/o woman with sudden onset of headache. Patient had a CT at another facility and was referred for further evaluation and treatment.

CT: click to enlargeCT: click to enlargeCT: click to enlarge


The first source image shows blood within the suprasellar cystern. The second image shows a round area of enhancement in the area of the basilar tip. A coronal MIP image of this area is provided. The two images below are 3-D reconstructions performed on a TeraRecon workstation using 0.5 mm isovolumetric voxels images from a 16 multidetector Toshiba CT scanner. These images demonstrate a 35 mm aneurysm arising off the tip of the basilar artery. Note the spasm in the M1 and A1 segments from subarachnoid hemorrhage.


Basilar Tip Aneurysm with spasm


Basilar tip aneurysms are the most common posterior fossa aneurysm but account for only about 3-5% of all intracranial aneurysms. They may become quite large causing a mass effect on the cranial nerves or brain stem. Subarachnoid hemmorhage is a common cause of intracranial arterial spasm.