An MRA (Magnetic Resonance Angiogram) scan is carried out exactly the same as an MRI scan apart from the use of dye which is administered through a needle in the back of your hand. This scan gives a clear picture which may show parts of the brain or other arteries that haven't shown up well on other tests. The dye used in this test has no side effects.
MRI or Magnetic Resonance Imaging is a scan which gives very detailed pictures of the brain.
As its name suggests, powerful magnets are used, which means that people with pacemakers or some types of metallic implants cannot have the test. Examples of these implants are cochlear implants, metal coils in the brain or some artificial heart valves. Furthermore, if you have any metal splinters ("flashes") in your eyes you can not have the test. Big implants like a hip replacement would not usually stop you having the test but you should tell the person doing the test if you have had one.
For this test you lie on a couch and your head is surrounded by a metal "helmet". The couch moves slowly into a tunnel to get the scan done. Some people feel a bit claustrophobic but to help, you are offered earphones and some music to make things more pleasant – this stops you hearing any machine noises too! There is a panic button if you really feel you need to get out. It is a painless test and takes about 15-20 minutes.