Tests for brain tumours

Physical examination

Your doctor will assess your nervous system to check how different parts of your brain and body are working, including your speech, hearing, vision and movement. This is called a neurological examination and may include:

• checking your reflexes (e.g. knee jerks)
• testing the strength in your arm and leg muscles
• walking, to show your balance and coordination
• testing sensations (e.g. if you can feel light touch or pinpricks)
• thinking exercises, such as simple arithmetic or memory tests.

The doctor may also test your eye and pupil movements, and look into your eyes using an instrument called an ophthalmoscope. This allows the doctor to see parts of the eye and its function – including your optic nerve, which sends information from the eyes to the brain. Swelling of the optic nerve can be an early sign of raised pressure inside the skull.

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Blood tests

You are likely to have blood tests to check your overall health. Most brain and spinal cord tumours cannot be found or monitored by a blood test. However, blood or special urine tests can be used to check whether the tumour is producing unusual levels of hormones, for example, if the pituitary gland is affected.

MRI scan

Your doctor will usually recommend an MRI (magnetic resonance imaging) scan to check for brain tumours and to help plan treatment. An MRI scan uses a powerful magnet and a computer to build up detailed pictures of your body. Let your doctor or nurse know if you have a pacemaker or any metallic object in your body (e.g. surgical clips after heart or bowel surgery). The magnet can interfere with some pacemakers, but newer pacemakers are often MRI-compatible.

For an MRI, you may be injected with a dye (known as contrast) that highlights any abnormalities in your brain. You will then lie on an examination table inside a large metal tube that is open at both ends.

The test is painless, but the noisy, narrow machine makes some people feel anxious or claustrophobic. If you think you may get upset, talk to your medical team before you go for the scan. You may be given medicine to help you relax or be able to bring someone into the room for support. You will have headphones or earplugs and you can press a distress button if you are worried at any time. An MRI takes 30–45 minutes.

The pictures from an MRI scan are generally more detailed than pictures from a CT scan (see below).

CT scan

Many people may have a CT (computerised tomography) scan, or it may be used if you are unable to have an MRI. This scan uses x-rays and a computer to create detailed pictures of the inside of the body.

Sometimes a dye (known as contrast) is injected into a vein before the scan to help make the pictures clearer. The contrast may make you feel hot all over and leave a bitter taste in your mouth. You may also feel like you are going to pee. These sensations usually only last a couple of minutes.

The CT scanner is a large, open doughnut-shaped machine. You will lie on a table that moves in and out of the scanner. It may take about 30 minutes to prepare for the scan, but the actual test takes only about 10 minutes and is painless.

Further tests

You may have some of the tests listed below to find out more information about the tumour and help your doctor plan treatment.

MRS scan

An MRS (magnetic resonance spectroscopy) scan is a specialised type of MRI. It is sometimes done at the same time as a standard MRI, but is more often used to check if a tumour has grown back after treatment. An MRS scan looks for changes in the chemicals in the brain.

MR tractography

An MR (magnetic resonance) tractography scan helps show the message pathways (tracts) within the brain, e.g. the visual pathway from the eye. It may be used to help plan treatment for gliomas.

MR perfusion scan

This type of scan shows the amount of blood flowing to various parts of the brain. It can also be used to help identify more features of the tumour, or may be used after treatment.

SPET or SPECT scan

A SPET or SPECT (single photon emission computerised tomography) scan shows blood flow in the brain. You will be injected with a small amount of radioactive fluid and then your brain will be scanned with a special camera. Areas with higher blood flow, such as a tumour, will show up brighter on the scan.

PET scan

For a PET (positron emission tomography) scan, you will be injected with a small amount of radioactive solution. Cancer cells absorb the solution at a faster rate than normal cells and show up brighter on the scan.

Lumbar puncture

Also called a spinal tap, a lumbar puncture uses a needle to collect a sample of cerebrospinal fluid (CSF) from the spinal column. The fluid is checked for cancer cells in a laboratory.

Biopsy

If scans show an abnormality that looks like a tumour, some tissue may be removed and tested. During a biopsy, the neurosurgeon makes a small opening in the skull and inserts a needle to take a small sample. Or they may take a biopsy through your nose. A biopsy may also be taken during surgery, while the neurosurgeon removes as much of the tumour as possible. A specialist doctor called a pathologist will examine the tissue under a microscope for signs of cancer and to work out the specific type of tumour.

Molecular testing 

A pathologist will run special tests on the biopsy sample to look for specific changes in the genes of the tumour cells (called molecular markers). These gene changes may happen during a person’s life (acquired) or be passed through families (inherited). The test results can help identify the features of the tumour so your doctors can recommend the most appropriate treatment. Ask your doctor about genetic testing.