Preparing for a brain MRI is straightforward compared to many other medical scans. You can eat, drink, and take your regular medications as usual beforehand. Most of the preparation comes down to what you wear, what you leave at home, and knowing what to expect once you’re inside the scanner.
Food, Drink, and Medications
Unlike abdominal MRIs, which require four to six hours of fasting, a brain MRI has no dietary restrictions. Eat a normal meal, stay hydrated, and take your daily medications on your usual schedule. The one exception: if your scan involves contrast dye and you have a history of kidney problems, your doctor may order a blood test beforehand to check how well your kidneys are filtering. The contrast agent used in MRIs is processed through the kidneys, so reduced kidney function can change whether contrast is safe for you.
What to Wear and What to Remove
The MRI machine uses an extremely powerful magnet, which means anything metallic on your body is a potential problem. Many facilities will give you a hospital gown, but if you’d rather wear your own clothes, stick to plain cotton with no zippers, snaps, hooks, or underwire. Athletic wear is a common pitfall. Yoga pants, compression shirts, and even some socks contain metallic threads or metal-based antibacterial compounds woven into the fabric. These can heat up during the scan and cause burns.
You’ll also need to remove all jewelry, watches, hair clips, belts, and piercings before entering the scan room. Leave valuables at home or in a provided locker. If your brain MRI involves imaging near your face or eyes, remove makeup, especially eye shadow and eyeliner, which often contain metallic particles. Nail polish with metallic or glitter finishes should come off too.
The Metal Safety Screening
Before every MRI, you’ll fill out a safety questionnaire about metal inside your body. This is the most important part of preparation, and it’s worth thinking through carefully before you arrive. The MRI’s magnetic field can move, heat, or interfere with metallic implants, so the technologist needs to know about anything you have.
Items that need to be disclosed include:
- Cardiac devices: pacemakers, defibrillators, pacing wires, and loop recorders
- Surgical implants: joint replacements, pins, screws, plates, rods, or surgical clips
- Coronary stents
- Cochlear implants or other ear devices
- Metal fragments: especially from welding, grinding, or metalworking, which can lodge near the eyes without you realizing
- Shrapnel or bullet fragments
- Drug infusion pumps or spinal cord stimulators
Some implants are labeled “MRI-conditional,” meaning they’re safe under specific conditions. Others are absolute contraindications. If you have any implanted device, gather the manufacturer name, model number, and implant card before your appointment. This lets the technologist verify compatibility quickly rather than delaying or canceling your scan.
If You Get Anxious in Tight Spaces
A standard MRI machine is a narrow tube about two feet wide. Your head will be positioned inside a head coil (a frame that fits around your skull), and you’ll lie still for the duration of the scan. If you’re claustrophobic, this is something to address well before scan day.
Talk to the doctor who ordered the MRI as soon as possible. They can prescribe a mild oral sedative for you to take before arriving. The key detail: do not show up expecting the MRI technologist to provide sedation. That hasn’t been standard practice for years. You need to get the prescription filled in advance, take it as directed before your appointment, and arrange for someone to drive you home afterward. Your chart will note the sedation, and the facility will require confirmation that you have a ride before releasing you.
For people whose anxiety is too severe for oral sedation alone, general anesthesia is an option, though it requires coordination with an anesthesia team and a longer appointment. Some facilities also offer open or wide-bore MRI machines, which have a larger opening and feel less confining. Ask when scheduling whether one is available.
What Happens During the Scan
A brain MRI takes about 30 minutes to an hour. If contrast dye is involved, expect the longer end of that range, since extra image sequences are captured after the injection. You’ll lie on a padded table that slides into the scanner. A lightweight coil is placed around your head to capture the images. The technologist will communicate with you through an intercom, and you’ll typically be given a squeeze ball to signal if you need to stop.
The machine is loud. It produces a series of banging, knocking, and buzzing sounds as it cycles through different imaging sequences. You’ll be given earplugs, and many facilities add headphones on top of that, aiming for at least 30 decibels of noise reduction combined. Some places let you listen to music through the headphones. The single most important thing you can do during the scan is hold still. Even small head movements blur the images and may require repeating sequences, which extends your time in the machine.
Contrast Dye: What to Know
Not every brain MRI uses contrast. Your doctor will specify whether yours requires it. If it does, a small IV line will be placed in your arm before or partway through the scan. The contrast agent highlights blood vessels, inflammation, and certain types of tissue, making abnormalities easier to spot.
The injection itself feels like a brief cool sensation in your arm. Some people notice a mild metallic taste. Serious allergic reactions are rare but possible, so mention any prior reactions to contrast agents or severe allergies when you check in. If you have kidney disease, your doctor should already be aware, since contrast clearance depends on kidney function. For people with significantly reduced kidney filtration, contrast may be minimized or avoided entirely.
Pregnancy and Brain MRI
MRI is considered safe during pregnancy. The American College of Obstetricians and Gynecologists classifies it alongside ultrasound as a preferred imaging technique for pregnant patients, noting no evidence of harm from the magnetic field. Theoretical concerns about tissue heating are minimal for brain scans, since the uterus is far from the scanner’s focal point.
Contrast dye is a different story. The agent used in MRI can cross the placenta and enter fetal circulation, and one large study found a small but measurable increase in adverse outcomes when contrast was used during pregnancy. For this reason, contrast is reserved for situations where the diagnostic benefit clearly outweighs the potential risk. If you’re pregnant and your brain MRI has been ordered with contrast, your doctor has already weighed this decision, but it’s reasonable to ask about it. For breastfeeding mothers, contrast is not a concern, and there’s no need to interrupt nursing afterward.
Day-of Checklist
Arriving prepared makes the process faster and reduces the chance of delays or rescheduling. Before you leave home, run through these steps:
- Eat and hydrate normally unless told otherwise
- Take your medications on schedule
- Wear metal-free clothing or plan to change into a gown
- Remove jewelry and piercings at home
- Skip metallic cosmetics on your face and nails
- Bring implant documentation if you have any medical devices
- Take prescribed sedation as directed and have a driver lined up
- Arrive 15 to 30 minutes early for paperwork and the safety screening
After the scan, you can go about your day normally unless you’ve taken a sedative. Results are typically interpreted by a radiologist and sent to your ordering doctor, with most reports available within a few business days.