MCA trifurcation aneurysm (CTA)

Case contributed by Roberto Schubert


CT performed for possible ischemic stroke and acute headaches.

Patient Data

Age: 70 years
Gender: Male

CT brain


Non contrast CT scan through the brain demonstrates no acute abnormality. Extensive periventricular low density is in keeping with small vessel ischemic change, most likely chronic. On the right a rounded density is seen in the sylvian fissure, which appears to be in continuity with the right MCA and contains a focus of peripheral calcification. The supraclinoid ICA on the left is bulbous. No evidence of subarachnoid hemorrhage. 

CT angiogram


Large aneurysm at the branching M1 segment of the right middle cerebral artery, giving off superior middle and inferior vessels (MCA trifurcation). No signs of recent hemorrhage. The left supraclinoid internal carotid artery is ectatic, incorporating the origin of the PCOM, but no focal aneurysm can be identified. 

Case Discussion

An aneurysm is a focal abnormal dilatation of a blood vessel. Cerebral artery aneurysms a true aneurysms mostly located near the skull base. They may present with acute subarachnoid hemorrhage (SAH), but can also be found incidentally on MRI or CT. As many as 20% of patients with subarachnoid hemorrhage have a positive family history. Multiple cerebral artery aneurysms are present in 20%.  In SAH, invasive treatment, either surgical or inventional, is always indicated, because of the high mortality of a second hemorrhage. The work-up must include a selective four-vessel catheter angiography of the carotid and vertebral arteries with compression tests. CT angiography is probably the best non-invasive imaging modality in cerebral aneurysms1.

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