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 hemorrhagic focus is noted in the left suprasellar region/inferior frontal lobe. Centrally and close to the left side of the suprasellar cistern, this hemorrhagic 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.
Conclusion:
Extensive subarachnoid blood with intraventricular extension is demonstrated, with a more focal hemorrhage 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.