Would a ct scan detect a brain annurysum and can they see the arteries by the cr scan?

No: Iv contrast ct is in order to detect aneurysm at the circle of Willis.

Tests for aneurysm: A standard head CT scan without contrast would probably not show an aneurysm unless it was large. A CT with contrast, or better, a CT angiogram or MR angiogram are much better at determining the presence of a cerebral aneurysm.

Yes and no: A CT scan, if it's given with intravenous contrast and the computer is configured the right way, can see aneurysms. That's called a CT angiogram. A non-contrast scan can see blood from a leaked aneurysm but doesn't really see the aneurysm itself very well. MRI is also very good for aneurysm. Arteries can be seen on CT with contrast. Without contrast, not so much.