What to Expect at Your First MRI Scan

You fill in a safety form, change out of anything metal, lie on a motorised table and slide into a tunnel. You wear earplugs or headphones because the scanner is very loud. You hold a call bell, the radiographer can hear and speak to you throughout, and you stay still for 15 minutes to an hour. You will not be told the result that day.

This is general information, not medical advice. If a symptom is worrying you, speak to your GP or call 111.

Before you arrive: the safety questionnaire

Every MRI department sends a safety questionnaire, and it is the most important piece of paper in the process. It asks about metal implants, surgical clips, stents, joint replacements, cochlear implants, pacemakers, defibrillators, insulin pumps, and any history of metal fragments in the eyes.

The scanner is a permanently powerful magnet — it does not switch off between patients. That is why the questions are asked twice, once on the form and again at the door.

Bring implant cards, model numbers and letters from previous operations if you have them. Whether a particular device is safe in a particular scanner is a decision the clinic's radiographer and MRI safety lead make, using manufacturer data and the field strength of their machine. It is not something to settle from an article or a forum. Our guide to MRI and metal implants covers what to gather before you go.

What you wear

Many departments give you a gown. Some will let you keep your own clothes on if there is genuinely no metal in them — no zips, buttons, underwiring, clasps or metallic thread. Soft joggers and a plain cotton t-shirt are the safest thing to turn up in.

Everything metal comes off and goes in a locker: jewellery, watch, glasses, hearing aids, hairpins, belt, coins, phone, keys, bank cards. Some trusts allow a plain wedding ring to stay on; ask rather than assume. Nail varnish and most make-up are fine, though metallic eyeshadow and some cosmetic glitter are not.

Tell the radiographer about tattoos, particularly large or older ones, and about any medicated patches. These are routine questions with routine answers, not accusations.

Walking into the room

The scanner room is cool, because the magnet is kept cold, and there is a constant background hum from the cooling system. The scanner itself is a large ring with a short tunnel through it and a motorised table in front.

You lie down, usually on your back. A coil — a plastic frame containing the receiving antennae — is positioned over or around the part being scanned. For a knee that means a shaped cradle; for a head, a frame that sits around your face with a mirror angled so you can see out of the tunnel.

You will be made comfortable with pads and cushions, and this is worth taking seriously. Comfortable people stay still, and staying still is the whole game.

The noise, and what protects you from it

MRI is loud in a way that surprises almost everyone the first time. The banging comes from the gradient coils, which switch rapidly during imaging and physically vibrate against their mountings inside the magnet.

The MRI physics literature puts acoustic noise commonly in the region of 110 to 130 decibels, with 3T scanners generally noisier than 1.5T. For scale, that is in the range of a pneumatic drill at close quarters. This is why hearing protection is mandatory: international equipment standards require protection sufficient to bring your exposure below 99 decibels.

Foam earplugs give roughly 15 to 25 decibels of reduction. Headphones or ear defenders used alongside them can reach 30 to 40. Many units offer music through the headphones, and some let you bring your own. Take the protection, wear it properly, and tell the radiographer if an earplug works loose between sequences.

The noise also comes in blocks. A sequence runs for a minute or three, stops, there is a pause, and then a different pattern of banging starts. The pauses are normal and not a sign that anything is wrong.

The call bell, and the intercom

You are given a call bell, sometimes called a squeeze ball or buzzer, to hold in your hand. Pressing it brings the radiographer into the room. North Bristol NHS Trust's patient information puts it simply: you will be given a call bell if you need the radiographer to come into the room.

The radiographer is behind glass in the control room, and the Royal United Hospitals Bath's leaflet describes it the way most units do — the radiographer will be able to see, hear and speak with you at all times. They will talk to you between sequences, tell you how long the next one runs, and answer you if you speak up.

Use the bell if you need to. Needing to cough, getting pins and needles, feeling panicky, or just wanting to know how much longer are all legitimate reasons. The worst outcome is not an interrupted scan; it is a set of blurred images that has to be repeated.

Why staying still matters so much

MRI builds each image from data collected over the whole sequence, not in a single instant. Move during a sequence and the whole sequence blurs, and the radiographer has to run it again.

For some body parts you will be asked to hold your breath for a few seconds at a time — chest and abdominal imaging in particular. The instructions come through the headphones and are short and specific.

Small, slow adjustments between sequences are usually fine if you ask first. Swallowing and blinking are fine. What matters is not moving the part being imaged while the banging is happening.

How long you are in there

Duration depends entirely on how much is being scanned and how many sequences the protocol calls for. The NHS says an MRI usually takes between 15 minutes and an hour, and can take longer. North Bristol NHS Trust describes roughly 20 minutes per body area, with patients in the department anywhere between 20 minutes and two hours.

These are typical appointment shapes rather than guarantees, and they follow the NHS figures above. Add time at both ends for changing, safety checks and, if contrast is used, for a cannula.

Contrast, if you need it

Some scans need an injection of a gadolinium-based contrast agent to make certain tissues or blood vessels stand out. If so, a small tube called a cannula goes into a vein in your arm, usually partway through the scan, and the injection happens while you stay in place.

Most people feel nothing beyond a cool sensation. There is a small risk of an allergic reaction, which is why departments ask about allergies and kidney function beforehand and keep you for a short observation afterwards. Whether contrast is appropriate for you is a decision the clinic's radiographer and radiologist make, based on your history and the question being asked.

If you are claustrophobic

You are not unusual. The Royal United Hospitals Bath's MRI leaflet notes that a small proportion of people, 2 to 5%, find MRI examinations difficult because of the partly enclosed nature of the scanner.

Say so when you book, not when you arrive. Departments have practical options: going in feet first where the anatomy allows, a mirror in the head coil, a cloth over the eyes, a companion in the room where safety allows, a wide-bore scanner, or mild sedation arranged in advance with your GP. Some private centres run open or upright scanners, which are a genuine alternative for some studies even though image quality differs.

Asking beforehand gets you a plan. Turning up and hoping usually gets you an abandoned appointment.

Nobody will give you the result on the day

This catches people out and feels like evasion, but it is not. The radiographer runs the scanner; a radiologist, a doctor who specialises in reading images, reports it afterwards — often the following day, sometimes with a subspecialty interest in that body part.

North Bristol NHS Trust says it flatly: you will not get any results at the time of your scan. The NHS gives a typical wait of one to two weeks for MRI results, because the images need to be looked at by a radiologist. Private providers are usually faster, commonly a few working days, with same-day or next-day reporting available at extra cost.

If the radiographer goes quiet or repeats a sequence, that is about image quality, not about something they have spotted. They are not permitted to interpret, and reading their body language will only cost you an evening. How long scan results take sets out realistic timings.

Frequently asked questions

Can I eat before an MRI? For most scans, yes, normally. Some abdominal and prostate protocols ask you to avoid a heavy meal or to fast for a few hours. Follow your own clinic's letter.

Can someone come in with me? Often yes, if they pass the same safety screening and the department allows it. Ask when booking rather than bringing someone on spec.

What if I need the toilet mid-scan? Press the call bell. The radiographer will bring you out. Going before you go in is the simplest prevention.

Is MRI safe in pregnancy? That is a decision for the clinic's radiographer and radiologist, made case by case. Tell them if you are or might be pregnant, before the scan rather than after.

Why did my scan take longer than the person before me? Protocols differ by body part and by clinical question, and extra sequences are sometimes added while you are on the table. It is not a sign that something has been found.

If you are still deciding where to have it done, you can compare MRI providers and prices on FindScan.