Middle Cerebral Artery Aneurysm
Last Updated: September 28, 2018
Approximately 30% of all ruptured cerebral aneurysms and 36% of all unruptured cerebral aneurysms originate along the middle cerebral artery (MCA) territory. They are usually located at the MCA bifurcation and often project laterally in the plane of the M1 segment.
MCA bifurcation aneurysms account for approximately 35% of all giant aneurysms. Because of their location, lateral projection, and attachment of the dome to the lobe, nearly 50% of ruptured MCA aneurysms present with intraparenchymal hematomas, and 80% of these are in the temporal lobe.
Any patient with a spontaneous hematoma adjacent to the Sylvian fissure, with or without associated subarachnoid hemorrhage, should undergo vascular imaging to rule out an underlying vascular anomaly. Complete vascular imaging is necessary; approximately 40% of patients with MCA aneurysms have multiple aneurysms, in contradistinction to approximately 20% of those with aneurysms in other locations. Moreover, mirror aneurysms can be seen in 13% of patients with MCA aneurysms.
Although MCA aneurysms are most commonly seen at the MCA bifurcation, they may a...