How are brain and spinal cord tumours diagnosed?

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. your ability to feel light touch or pinpricks)
• brain exercises, such as simple arithmetic or memory tests.

The doctor may also test eye and pupil movements, and look into your eyes using an instrument called an ophthalmoscope. This allows the doctor to see 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.

You are likely to have blood tests to check your overall health. Blood tests can also be used to check whether the tumour is producing unusual levels of hormones, which could mean the pituitary gland is affected.

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 other 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 (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 become distressed, mention it beforehand to your medical team. You may be given medicine to help you relax or you might be able to bring someone into the room with you for support. You will usually be offered headphones or earplugs and can press a distress button if you are worried at any time. An MRI takes 30–45 minutes and you will be able to go home afterwards.

The pictures from an MRI scan are generally more detailed than pictures from a CT scan.

Before having scans, tell the doctor if you have any allergies or have had a reaction to dyes during previous scans. You should also let them know if you have diabetes or kidney disease, or are pregnant or breastfeeding.

A CT (computerised tomography) scan uses x-rays to take many pictures of the inside of the body and then compiles them into detailed, cross-sectional pictures. Contrast may be injected into a vein to help make the scan pictures clearer. It may make you feel hot all over and leave a bitter taste in your mouth. You may also feel the need to pass urine. These side effects usually ease within minutes.

The CT scanner is a large, 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. You will be able to go home when the scan is complete.

Before having scans, tell the doctor if you have any allergies or have had a reaction to dyes during previous scans. You should also let them know if you have diabetes or kidney disease, or are pregnant or breastfeeding.

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 can be done at the same time as a standard MRI. It 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 can 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.

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.

Surgical removal of tissue (biopsy or resection) – If scans show an abnormality that looks like a tumour, some tissue may be removed so it can be examined under a microscope. During a biopsy, the neurosurgeon makes a small opening in the skull and inserts a needle to take a small sample. During a resection, 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 type of tumour.

Molecular testing – A pathologist will run special tests on the biopsy sample to look for specific mistakes in the structure of the tumour cells (called molecular markers). Some mistakes are found only in cancer cells (acquired gene changes) and some are passed through families.

The test results can help identify the features of the tumour so your doctors can recommend the most appropriate treatment. For more information about testing for gene faults (genetic testing), talk to your doctor or call Cancer Council 13 11 20.