Medical terms. Stroke is technically a catch-all phrase for bleeding or lack of blood flow to a brain area from a blocked artery. An aneurysm usually causes bleeding. A computed tomography scan (ct or cat scan) is the quickest way to show bleeding into or around the brain. It can show vessel blockage and lack of blood flow if the affected area is large enough, if questions remain a MRI scan can show more.
Imaging is standard. Although there may be some historical and clinical findings that can help distinguish these, in industrialized societies the gold standard would be imaging, probably with mri. "stroke" is a very broad term that can encompass embolism, intracranial bleeding, and atherosclerotic disease of the brain; either embolism or aneurysm could cause a type of "stroke".