Brain MRI scanner: what to expect

You lie on a table that moves into a tunnel-shaped machine. The scan is noisy, and keeping your head still helps produce clear pictures. Some examinations use an injected contrast agent to make particular tissues or blood vessels easier to assess.

MRI can show the brain, its coverings, fluid spaces and nearby structures in different types of image sequence. Clinicians use it to investigate symptoms, characterise an abnormal area, plan treatment, or compare changes across follow-up scans.

An MRI finding does not by itself always identify exactly what an abnormal area is. The radiologist interprets its location and imaging pattern alongside symptoms, examination findings and earlier scans. Further imaging or a biopsy may sometimes be needed.

Complete the safety questionnaire accurately. Report a pacemaker, aneurysm clip, cochlear implant, medicine pump, metal fragment, previous surgery, kidney problems, pregnancy or possible pregnancy. The imaging team must confirm whether each device or implant is compatible with the scanner.

Remove metal objects as instructed and tell staff if enclosed spaces make you anxious. Ear protection and an intercom are provided, and you can communicate with the radiographer. If contrast is planned, mention previous contrast reactions and follow the centre's instructions about food, drink and medicines.

Call emergency services for a first seizure, sudden facial droop or limb weakness, new trouble speaking, loss of consciousness, severe confusion, or an abrupt and unusually intense headache. These symptoms need urgent clinical assessment rather than waiting for a scheduled MRI.

After contrast, alert staff immediately to breathing difficulty, swelling of the face or throat, widespread hives, or feeling faint. For milder symptoms after leaving, contact the imaging service or seek medical advice using the discharge instructions provided.

Ask whether contrast is expected, whether an implant needs documentation, how to manage claustrophobia, and who will explain the result. If this is a follow-up examination, ask which earlier images should be available for comparison and what clinical decision the scan is intended to inform.