Subarachnoid haemorrhage: internal carotid artery terminal aneurysm

Case contributed by Prof Peter Mitchell


Fall, trauma, unconscious.

Patient Data

Age: 23
Gender: Male


Extensive subarachnoid blood is demonstrated throughout both cerebral hemispheres. Blood fills the lateral, third and fourth ventricles. The lateral ventricles are mildly prominent for the patient's age. A large haemorrhagic focus is noted in the left suprasellar region/inferior frontal lobe measuring 28 x 20 mm. Centrally and close to the left side of the suprasellar cistern, this haemorrhagic focus is of a lower attenuation.

The basal cisterns are effaced by blood. There is no evidence of transtentorial or tonsillar herniation.

There is mild diastasis of the inferior aspect of the right lambdoid suture. No other skull fracture is demonstrated. The paranasal sinuses and mastoid air cells are clear.


Extensive subarachnoid blood with intraventricular extension is demonstrated, with a more focal haemorrhage in the left suprasellar/posterior frontal lobe region. These findings are suggestive of an aneurysmal bleed, with aneurysm most likely located in the region of the terminal left ICA.

Conventional aortic arch anatomy. The cervical carotid and vertebral arteries are free of significant stenoses or ectasias.

Left terminal ICA aneurysm projecting anterosuperiorly measures 13 x 7 mm, with a 5 mm neck, surrounded by previously described haematoma. No other aneurysms or vascular malformations are demonstrated. The remainder of the circle of Willis is unremarkable.


Left terminal ICA 10 x 7 mm aneurysm with a 5 mm neck and surrounding haematoma.


Diagnostic angiography superiorly and anteriorly projecting 13 x 7 x 5 mm terminal left internal carotid artery aneurysm. EVD in position. No other intracranial aneurysms identified. There is a small daughter aneurysm at the base of the aneurysm, medial side.

Balloon assisted coil embolisation.

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Case information

rID: 34461
Published: 22nd Feb 2015
Last edited: 28th Jun 2017
Inclusion in quiz mode: Included

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