An MRI is painless, but it’s not exactly comfortable. You’ll lie still on a narrow table that slides into a large tube-shaped magnet, and for anywhere from 15 to 90 minutes, you’ll hear loud, rhythmic banging and buzzing while the machine captures detailed images of your body. There’s no radiation involved, and you won’t feel the magnetic field itself. But the noise, the tight space, and the need to stay perfectly still make it an experience most people remember vividly.
Before You Go In
The process starts with a safety screening questionnaire, and it’s more thorough than you might expect. Because the MRI uses an extremely powerful magnet, anything metallic in or on your body is a potential problem. You’ll be asked about pacemakers, surgical clips, joint replacements, stents, cochlear implants, medication pumps, and any other implanted devices. You’ll also be asked whether you’ve ever worked around a metal lathe or had metal shavings near your eyes, and whether you have tattoos or permanent makeup (some older inks contain metallic particles that can heat up).
You’ll change into a hospital gown and remove jewelry, watches, hearing aids, hair clips, and anything else with metal. Even medication patches need to come off, since some contain metallic components that can cause burns. If you’re pregnant or could be pregnant, let your team know beforehand.
What the Machine Looks and Feels Like
A standard closed-bore MRI is essentially a narrow tunnel about 60 centimeters (roughly two feet) wide, surrounded by a ring of powerful magnets. You lie on a padded table that slides you into the center. The ceiling is close to your face, typically just a few inches away, and the space is snug enough that your shoulders may nearly touch the sides. There’s usually a small fan blowing air through the bore and some lighting inside, but it still feels enclosed.
Open MRI machines exist as an alternative. These use two flat magnets positioned above and below you with open space on the sides, which removes much of the tunnel feeling. The trade-off is image quality: open MRIs don’t produce images as sharp or detailed as closed-bore machines, so your doctor may specifically need the closed-bore version depending on what they’re looking for.
The Noise
This is the part that catches most people off guard. MRI machines are loud. The sounds come from the rapid switching of electrical currents inside the machine’s gradient coils, which vibrate mechanically and produce a range of banging, knocking, buzzing, and jackhammer-like rhythms. Each imaging sequence has its own distinct pattern, so the sounds change throughout the scan.
On a standard 3-Tesla machine (the most common high-field type), time-averaged sound levels typically exceed 95 decibels and can peak above 105 decibels. For reference, that’s comparable to standing near a running lawnmower or a loud concert. The FDA caps allowable MRI sound at 140 decibels, and some sequences on more powerful machines approach 130. You’ll be given earplugs, foam ear protection, or noise-canceling headphones before the scan starts. Many facilities also pipe in music through the headphones, which helps.
Staying Still
You need to remain as motionless as possible for the entire scan. Even small movements can blur the images and force a sequence to be repeated, which adds time. If your head or brain is being scanned, your head may be placed in a padded frame or cage-like coil to keep it in position. For knee or joint scans, the area is usually wrapped in a specialized coil that looks like a brace.
A brain or head MRI typically takes 30 to 60 minutes. A lumbar spine scan runs about the same, though adding contrast dye can extend it to 45 to 90 minutes. Knee MRIs generally take 30 to 60 minutes. The technologist will tell you before each sequence how long it will last, and there are brief pauses between sequences where you can breathe more freely, though you still shouldn’t shift position.
If You Get Contrast Dye
Some scans require a contrast agent injected through an IV in your arm, usually partway through the appointment. The contrast contains gadolinium, a substance that makes certain tissues show up more clearly on the images. The injection itself feels like any standard IV, but many people notice a metallic taste in their mouth shortly after, along with a warm sensation that spreads briefly through the body. Some people feel mildly tired or nauseated afterward, and slight bruising at the injection site is common.
Allergic reactions to gadolinium-based contrast are uncommon. Mild reactions (things like hives or a brief rash) occur in roughly 0.07% to 2.4% of cases. Moderate reactions are rarer, at 0.004% to 0.7%, and severe, life-threatening reactions happen in fewer than 0.01% of injections. In a study of over 10,600 contrast-enhanced MRI exams, 75% of the reactions that did occur were mild.
Dealing With Claustrophobia
Feeling anxious about the enclosed space is one of the most common concerns, and it’s not rare. In one study of 939 MRI patients, about 14% needed some form of sedation (oral, intravenous, or general anesthesia) to get through the scan. That means the staff has seen this many times and has a playbook for it.
If you know you’re claustrophobic, tell the scheduling team when you book the appointment. Options typically include a mild oral sedative taken before you arrive, which takes the edge off without putting you to sleep. You’ll usually be given a squeeze-bulb alarm to hold during the scan so you can signal the technologist at any time. The technologist can also talk to you through a speaker inside the bore between sequences. Some people find it helpful to close their eyes before the table moves in and keep them closed for the duration, since the visual of the tight space is often the biggest trigger.
If your scan is compatible with an open MRI, that’s another route worth asking about. The open design eliminates the tunnel entirely, which resolves the issue for many people, though not all imaging centers have one available.
What You Feel During the Scan
The magnetic field and radio waves used in MRI are not felt directly. There’s no pain, no tingling, and no sensation of being scanned. What you do feel is the hard table beneath you (padding helps, but it’s still firm over a long scan), the cool air from the bore’s ventilation fan, and occasionally mild warmth in the area being imaged, which is normal. If you have any metal implants that were cleared as MRI-safe, you may notice a faint warming sensation near them.
The hardest part for most people is simply the combination of lying still, the loud noise, and the enclosed space over a sustained period. It’s not painful, but it can be mentally taxing. Bringing a plan for how to pass the time, whether that’s listening to the music offered, counting breaths, or mentally working through a podcast you listened to earlier, makes a real difference.
After the Scan
Once the final sequence finishes, the table slides you out and the technologist helps you up. If you didn’t receive sedation or contrast, there’s no recovery time. You change back into your clothes and leave. If you had contrast dye, you’ll be encouraged to drink extra water to help flush it from your system. If you took a sedative, you’ll need someone to drive you home.
Results aren’t immediate. A radiologist reviews the images and sends a report to the doctor who ordered the scan, which typically takes anywhere from a few hours to a few days depending on urgency and the facility. You won’t get results from the technologist in the room.