In short
MRI of the head is the main test when a brain tumour is possible. CT is sometimes used first in an emergency. A biopsy or the operation itself obtains tissue so a pathologist can name the tumour. Blood tests do not diagnose most primary brain tumours. This is general information. Urgent symptoms need 999 or A&E, not a webpage.
Imaging shows where a mass is. Tissue type decides treatment. Some tumours are diagnosed only after surgery.
MRI or CT first?
A&E often starts with CT because it is fast. MRI gives more detail for planning. Contrast dye may be used unless it is unsafe.
When is a biopsy done?
If the tumour cannot be fully removed, or the type is unclear on scans, a stereotactic biopsy samples tissue. Risks and benefits are explained by the neurosurgeon.
Help a patient afford cancer care
Gifts go to the Cancer Emergency Appeal’s wider fund for patients who cannot pay. They do not buy a guaranteed treatment or result.
Donate to cancer careWhat about lumbar puncture?
It is not the first test for a solid brain mass. It is used in some cancers that involve the spinal fluid. Your team will say if it is needed.
Key takeaways
- MRI is the key diagnostic scan.
- Tissue type comes from biopsy or surgery.
- Blood tests do not diagnose most primary brain tumours.
Care like this is out of reach for millions
The diagnosis, screening and treatment described here are routine in the UK. In Pakistan, Indonesia and Malaysia, poverty can put them out of reach. The Cancer Emergency Appeal raises funds towards clinically recommended care for patients who cannot pay; gifts go to the wider fund and do not buy a guaranteed treatment or result.
Frequently asked questions
Can I have MRI with metal implants?
Some implants are MRI-conditional. Radiology checks this before the scan.
Does a clear CT rule a tumour out?
Not always. MRI is more sensitive. Specialists decide if another scan is needed.
Does WAN offer UK MRI?
No. We fund overseas treatment access.
Editorial summary of published sources. A named oncology clinician has not signed off this guide. Use it to prepare questions for your healthcare team, not to diagnose symptoms or choose treatment. Editorial responsibility: Kaiser Khan. Updated 4 October 2026.
What are the sources for this guide?
Follow the original guidance for its evidence, dates and limitations. General background references are not a clinical review of this page.