What imaging tests are done on the brain?
• Computerized axial tomographic scan (CT or CAT scan) — Uses X-rays to generate an image of the brain. Doctors use CT to determine whether a stroke has occurred and, if so, what kind. (Ischemic strokes are caused by a clot that blocks an artery. Hemorrhagic strokes result from a ruptured blood vessel in the brain causing bleeding into brain tissue.) CT scanning takes from 5 to 10 minutes to complete (mostly less than 5 minutes). The test causes no discomfort. • Magnetic resonance imaging scanning (MRI) — The stroke patient is placed into the MRI scanner. This scanner has a magnetic field in which the head is subjected to bursts of energy of a known magnetic frequency. The response of the brain cells to these bursts of energy is detected as signals that ultimately generate an image of the brain. MRI can give very accurate images of the brain. These are used to determine the presence, location and size of aneurysms and arteriovenous malformations, which are potential sources for hemorrh
