Further tests for diagnosing brain tumours
At the hospital you may have to have some of the following tests. Your doctor will select the most suitable ones for your particular situation and symptoms.
Most of these tests can be done as an outpatient if appropriate, so you’ll be able to go home shortly after the test.
Brain MRI (magnetic resonance imaging) scanBack to top
This test uses magnetic fields to build up a detailed picture of the inside of your head. The scanner is a powerful magnet so you may be asked to complete and sign a checklist to make sure it’s safe for you. The checklist asks about any metal implants you may have, such as a pacemaker, surgical clips or bone pins. You should also tell your doctor if you’ve ever worked with metal or in the metal industry, as very tiny fragments of metal can sometimes lodge in the body. If you do have any metal in your body, it’s likely that you won’t be able to have an MRI scan. In this situation, another type of scan can be used.
Before the scan, you’ll be asked to remove any metal belongings including jewellery. Some people are given an injection of dye into a vein in the arm, which doesn’t usually cause discomfort. This is called a contrast medium and can help the images from the scan show up more clearly. During the test, you’ll lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It’s painless but can be slightly uncomfortable, and some people feel a bit claustrophobic. It’s also noisy, but you’ll be given earplugs or headphones. You can hear, and speak to, the person operating the scanner.
Specialist MRI scans called MRS (magnetic resonance spectroscopy) may sometimes be used to help diagnose a brain tumour. MRS scans look at the chemicals in the tumour. Another specialised type of MRI scan, called MRA (magnetic resonance angiography) looks at the blood vessels of the tumour.
Brain CT (computerised tomography) scanBack to top
A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body. The scan takes 10–30 minutes and is painless. It uses a small amount of radiation, which is very unlikely to harm you and will not harm anyone you come into contact with. You will be asked not to eat or drink for at least four hours before the scan.
You may be given an injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It’s important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection.
You’ll probably be able to go home as soon as the scan is over.
Someone having a CT scan
View a large version of the image of someone having a CT scan
The doctors may need to take a small part of the tumour (a biopsy) to find out exactly what type of tumour you have.
PET (positron emission tomography) scanBack to top
A PET scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body.
A very small amount of the mildly radioactive substance is injected into a vein, usually in your arm. Tumours normally absorb more of the glucose and the radioactivity shows up on the scan.After the injection you may be asked to lie in a dark room with your eyes closed. You’ll then be taken to the scanning room and asked to lie on a couch with the scanning ring around you. The dose of radiation you receive is no more than a normal x-ray.
A PET scan isn’t routinely used to diagnose a brain tumour, but it may help to tell whether a tumour is growing and whether it is cancerous (malignant) or benign. PET scans aren’t available in all hospitals, and you may have to travel to a hospital some distance away to have one.
SPECT (single photon emission computerised tomography) scanBack to top
This test is similar to a PET scan. It looks at blood flow through the brain.
You are given an injection of a very mild radioactive substance, usually in your arm. This substance travels in the blood to the brain. Then, in the scanning room, pictures (scans) of the brain are taken.
Blood tests and chest x-raysBack to top
There isn’t a specific blood test that can detect brain tumours, but you may have blood tests to check your general health. A chest x-ray may also be done as part of a general health check.