How to Prepare for an MRI Scan: Metal, Fasting and Claustrophobia
What to do before an MRI: metal and implant checks, whether to fast, what to wear, how long it takes, how to cope with claustrophobia, and what to bring to the centre.
Key takeaways
- Metal is the main safety issue. Tell the centre about every implant, device, surgery and any metal fragment, especially in the eye.
- Most MRIs need no fasting. Abdominal, MRCP and some pelvic scans ask for four to six hours without food.
- The scan takes 20 to 60 minutes, is loud, and needs you to lie very still. Movement is the commonest reason for a repeat.
- Claustrophobia can be managed: ask for a wide-bore or open machine, an eye mask, music, a feet-first position, or mild sedation arranged in advance.
Most of what goes wrong on MRI day is avoidable: a forgotten metal implant, a scan repeated because of movement, an abdominal scan wasted because the patient ate breakfast, or someone too claustrophobic to finish. None of it is anyone’s fault when nobody explains the process. This guide is the explanation, in the order you will need it.
Quick answer
Tell the centre about every implant, device and past surgery. Fast for four to six hours only if it is an abdominal or MRCP scan. Remove all jewellery and metal, wear loose clothes without metal, and expect 20 to 60 minutes of loud noise while lying still. If you are claustrophobic, ask in advance for a wide-bore machine, music, an eye mask or sedation.
Before the day: the safety check
An MRI machine is a very strong magnet that is always on. Loose metal can be pulled into it, and some implants can heat, move or stop working. Every centre uses a screening form; fill it in honestly and completely.
Tell the centre in advance if you have
A pacemaker, defibrillator, cochlear implant, nerve stimulator or insulin pump. An aneurysm clip, heart valve or stent. Any metal fragment in the eye or body, including from welding, grinding or an old injury. Joint replacements, plates or screws. A recent surgery. A pregnancy or possible pregnancy. Bring device cards or operation notes if you have them.
Most modern implants, including joint replacements, dental work and many stents, are safe. The point of the form is to identify the few that are not, and to plan safely for those that need a special protocol.
Do you need to fast?
For brain, spine and joint MRIs, usually not. For the abdomen, MRCP and some pelvic studies, centres ask for four to six hours without food, so that the stomach and gallbladder are in a predictable state. Water is often allowed. Diabetics who are asked to fast should ask the centre and their doctor how to adjust medicines. If contrast is planned, see the contrast guide.
What to wear and remove
Wear loose, comfortable clothing without zips, hooks, metallic threads or underwire; many centres provide a gown. Remove all jewellery, including mangalsutras, nose pins, toe rings and hairpins, plus watches, hearing aids, removable dentures, belts and spectacles. Leave phones, cards and keys in the locker, since the magnet erases cards. Some bindis, eye make-up and hair products contain metallic particles; remove them for head scans.
What happens during the scan
You lie on a padded table that slides into the machine, with a coil placed around the body part being scanned. The machine makes loud knocking and buzzing sounds, so you will be given ear plugs or headphones. Each set of images takes a few minutes and you must lie very still; the technologist will talk to you between sets. You hold a call bell throughout. If contrast is needed, it is injected through a small cannula partway through. Total time is usually 20 to 45 minutes.
Coping with claustrophobia
Tell the centre when you book, not on arrival. Useful options include a wide-bore or open machine, which feels far less enclosed; going in feet first for scans that allow it; an eye mask or keeping eyes closed from the start; music through headphones; a family member allowed to sit in the room after their own safety check; and practising slow breathing. For severe anxiety, your doctor can prescribe a mild sedative to take beforehand, in which case someone else must drive you home.
What to bring
Your doctor’s prescription stating exactly what is to be scanned and why, previous scan reports and image CDs or links for comparison, a list of your medicines and any allergies, device or implant cards, and identification. Ask before leaving how and when you will get the report and the images; always collect both. The MRI report guide explains what comes back, and the cost guide helps you check the quote.
Frequently asked questions
Do I need to fast before an MRI?
For most MRIs of the brain, spine and joints, no. For the abdomen, especially the liver, pancreas and bile ducts (MRCP), and for some pelvic scans, you will usually be asked not to eat for four to six hours. Follow the centre's written instructions, and keep taking your regular medicines unless told otherwise.
How long does an MRI take?
Usually 20 to 45 minutes, sometimes up to an hour for several body parts or scans with contrast. Plan for extra time at the centre for the safety form, changing and waiting.
Can I wear jewellery, a mangalsutra or a bindi during an MRI?
Remove all jewellery, including mangalsutras, chains, rings, earrings, nose pins and hairpins, and leave watches, cards and phones in the locker. Bindis and some cosmetics can contain metallic particles, so remove them for head scans, and avoid eye make-up. Ask the centre about anything you cannot remove.
Is an MRI safe with tattoos?
Usually yes. Some older or dark tattoo inks contain metal and can warm slightly during the scan. Tell the technologist, who can place a cool compress on the area; stop the scan by pressing the call bell if a tattoo feels hot.
Can I have an MRI if I have a pacemaker?
Many modern pacemakers and defibrillators are labelled MR-conditional and can be scanned under a specific protocol with a cardiologist's programming. Older devices may not. Never go into the scan room without telling staff; bring your device card.
Sources
Dr. Garima Panse is a medical doctor who writes plain-language guides for Indian readers on skin health, heart health, brain and nerves, medical imaging and everyday medicine. Every guide lists its sources, shows the date it was last reviewed, and says when to see a doctor in person.
This guide is for general education and reflects the evidence available on the last reviewed date. It is not a diagnosis, a prescription or a substitute for seeing a doctor who can examine you. If you have symptoms that worry you, or the guide tells you to see someone, please do. Full disclaimer.