Difference between a CT scan and an MRI Scan

Having a CT scan involves lying on your back, with your head positioned inside the scanner. It takes about five to ten minutes and is completely painless. The doctor may want a scan done after dye is injected into one of your veins, so the injection might be a bit painful. If you are allergic to iodine, make sure the doctor or radiographer knows – in most cases a scan using a dye is not essential.

An MRI scan also involves your lying on your back, and you go into an enclosed tunnel; the machine is quite noisy. (They may play you your favorite music while the scan is being done, to make it slightly more pleasant.) As with a CT scan, it takes only a few minutes, depending on how many bits have to be scanned. The MRI machine contains a very powerful magnet, so, if you have any metal bits inside you or a pacemaker, you probably won’t be able to have the scan. (It is also very good at wiping clean the magnetic strips on your credit cards!) The tunnel can cause problems for people who get claustrophobic but, because the MRI scan can provide information much more easily than the alternatives, if your doctor advises one, it might be best to grit your teeth and get on with it. If you really think it might be too much, ask if it is possible to have a short-acting sedative to help calm your nerves.