Does ct in er rule out both hemmorgic and ischemic stroke if patient exhibiting symptoms or is mri required ?

A CT can rule out a hemorrhagic stroke when the stroke is happening. A CT does not usually show an ischemic stroke during the time when it is happening. After a couple of days the CT will however also show an ischemic stroke. An MRI will show either type of stroke even when it is occurring.

If stroke symptoms are present and there is the hope of reversal using TPA, a CAT scan is fast and can rule out bleeding. MRI is useful later if a fixed lesion has occurred.