How is a brain tumour diagnosed?
The first step is to report all symptoms to a GP. It is helpful to write them down and include a timeline that shows what each symptom is, when they began, and how frequently they occur.
If your GP suspects the presence of a brain tumour they will refer you to a neurologist for further tests. The only definite way to establish if a tumour is present is to use a CT or MRI scan, for which the neurologist can refer you.
Unfortunately, some patients may experience a seizure or other symptom that means that their referral could be via an Accident and Emergency department. In such cases, a scan may be done immediately and a referral made directly to a neurosurgeon.
Multi-disciplinary team (MDT) for brain tumour patients
Once scan results are available, patients will be referred to a specialist multidisciplinary team (MDT) at their nearest neuro-oncology hospital. Scan results, alongside all other diagnostic tests and the full medical history of the patient will be discussed,
then the MDT decide as a group what the best course of treatment should be. This ensures that every patient benefits from a range of expert opinions.
What is a CT scan for a brain tumour?
A CT scan uses X-rays to produce images of the brain, which are interpreted by a neuroradiologist to confirm if a mass is present. CT stands for “computed tomography,” meaning that a computer controls the movement of the scanning equipment, which consists of a tube that spins rapidly around the patient who is lying safely inside the CT machine.
Whilst a CT scan can show the size, shape and location of a brain tumour, an MRI scan is then required in order to gain more detailed information.
CT scans are good for X-rays of bones, so they may be used for meningioma to assess if there is any bone involvement, if this is suspected after an MRI scan.
What is an MRI scan for a brain tumour?
An MRI scan involves lying down on a comfortable bench that then slides inside a large tube, open at both ends, that contains the scanner. Patients are offered earplugs and headphones as the scanner makes loud noises as it takes the images, caused by the scanner coils being turned on and off. The headphones and an intercom ensure that patients can both hear and speak to the people operating the scanner at all times, who are called radiographers. The scan can last up to an hour, depending on the types of images required.
MRI stands for “magnetic resonance imaging” because it uses a combination of magnetic fields and radio waves to produce a detailed image of the brain. All patients with a suspected brain tumour should be offered a standard structural MRI scan.
In addition, advanced MRI techniques such as MR perfusion and MR spectroscopy are used to clarify the diagnosis, including whether a tumour is low-grade (slow growing) or high-grade (fast growing). These techniques require the patient to be given an injection
of contrast dye into their arm or through an IV (intravenous) port, to enhance the MRI images.
What is MRI brain perfusion?
The contrast dye enhances areas of the brain where there is increased blood flow, indicating that the cells in that area are requiring extra nutrients (bought to them in the blood) in order to grow more quickly. The increased blood flow therefore indicates
cancerous areas, particularly those classified as high-grade (fast growing) tumours.
What is MRI brain spectroscopy?
MRI spectroscopy compares the levels of different products of metabolism (metabolites) in the tumour with that of the normal brain tissue surrounding it.
- Amino acids
- N-acetyl aspartate
The higher the grade, the more quickly a tumour is growing and hence the more energy it needs. The more energy it uses, the higher the levels of these metabolites because they are the “end products” of the energy cycle in each cell. A healthy brain cell will produce different levels of these metabolites when compared to a tumour cell because it uses energy in a different way, and levels can vary across tumour types as well as grades.
MRI spectroscopy can also be invaluable when assessing if a tumour is actively recurring or whether the image simply shows areas that have died after treatment (necrosis), which can sometimes be difficult to tell apart just by looking at the images obtained
by a standard MRI scan.
Lumbar puncture for brain tumour diagnosis
For certain rare tumour types such as embryonal tumours, for example, patients may be offered a lumbar puncture. Colloquially known as a spinal tap,
the procedure involves a very fine needle being inserted into the lower (lumbar) area of the spine so that a sample of the cerebral spinal fluid (CSF) can be taken for analysis.
How are molecular markers used to diagnose a brain tumour?
Once scan results have confirmed the presence of a tumour, a patient will be referred for a biopsy in order to make a more accurate diagnosis. The only exception to this is when a tumour is in a position that would make this procedure too risky to undertake.
A biopsy is a neurosurgical operation under general anaesthetic in which a thin hollow needle is inserted into the tumour, and a sample of the cells that it contains is taken out for analysis. A biopsy can be a procedure by itself, or it can happen as part of a neurosurgical operation to remove as much of the tumour as possible.
Only when a tissue sample is investigated in a laboratory by a neuropathologist can finer details about the tumour be clarified. The sample is viewed through a microscope (known as histopathological assessment) and classified by the physical characteristics
that can be observed (known as the phenotype). Additional tests are then run to look at the genetic characteristics of the tumour (genotype). The combined information then guides the treatment plan, and is particularly relevant when identifying any
drugs that may be used to influence any specific genetic pathways that are driving tumour growth.
How do I get a second opinion about my brain tumour on the NHS?
Unfortunately, brain tumour symptoms can often be mistaken for other conditions and for some patients gaining a referral to a neurologist from their GP takes a number of visits. Under such circumstances it is reasonable to ask for a second opinion from a different doctor, but this is not a legal right in the UK.
Once diagnosed with a brain tumour and under the care of a consultant, if the patient or their family feel that it is necessary then arranging a second opinion should be discussed with the GP and hospital medical team. They should be happy to offer advice about other medical professionals who have a specialist interest in a rare type of tumour, or extensive experience in any specialist neurosurgery that may be recommended (for example, awake craniotomy).
Patients may also wish to explore the possibility of participating in a clinical trial before deciding where to be treated.
How to find a clinical trial
Our Member Charity brainstrust offer support for every aspect of a brain tumour experience, including helping to arrange second opinions in the UK and abroad.
Who can help with problems related to diagnosis and treatment?
Every hospital should have a PALS office (Patient Advice and Liaison Service). The PALS team are there to help with health-related questions, to help resolve concerns or problems with any NHS service, and to signpost local support services both within and outside the NHS.
You can find your local PALS office by using the search box on the NHS PALS website.