Blood tests
You may have blood tests to check for specific chemical markers in the blood. Some tumours, such as pituitary adenoma or germ cell tumours may change the level of particular hormones and your doctor will check for these.
 
CT scan
A CT scan is a computerised scan using X-rays. Brain tumours usually show up on this type of scan. You may have a CT scan of the brain. When you have your CT scan, you have an injection during or just before the scan. This is called a contrast medium. It is a dye that circulates in your bloodstream to the brain and makes the CT pictures of the brain clearer. We have detailed information about having a CT scan in the section about cancer tests.

MRI brain scan
MRI scans use magnetic fields to create a picture of body structures. These scans usually give a very clear picture of the brain and will almost certainly show up any brain tumour that is present. You usually have an injection of contrast medium to make the scan clearer.

Specialised MRI scans called magnetic resonance angiography (MRA scans) can show the blood vessels in the brain. Magnetic resonance spectroscopy (MRS scans) look at chemicals in the tumour. Perfusion MRI scans look at the blood flow in different parts of the brain and diffusion (DTI) how the parts of the brain are connected and if these connections are damaged.

Testing your nervous system
Testing your nervous system is called a neurological examination. It involves a number of simple tests. Your doctor may do the following.
-- Test your muscle strength by asking you to squeeze their hand with each of yours or push against their hand with your feet
-- See if you have any areas of numbness
-- Test your reflexes by tapping your knee with a rubber hammer
-- Check if there are any weaknesses in the muscles of your face, eyes and tongue
-- Look into the back of your eyes to see if there are any changes caused by increased pressure in the brain
-- Ask you some questions to see how you follow commands, what your memory is like and can you read and write.