MRI (Magnetic Resonance Imaging) is a non-invasive medical imaging technique that uses powerful magnetic fields and radio waves to create detailed images of the body's internal structures. Unlike X-rays and CT scans, MRI does not use ionizing radiation. It's particularly effective for imaging soft tissues, the brain, spinal cord, joints, and organs.

MRI is considered very safe for most patients as it does not use ionizing radiation. However, the strong magnetic field can be dangerous for people with certain metal implants, pacemakers, or other electronic medical devices. Pregnant women should inform their doctor, though MRI has been used safely in pregnancy when medically necessary. Gadolinium contrast agents are generally safe but may pose risks for people with severe kidney disease.

How long does an MRI take?

A typical MRI scan takes 30-60 minutes, depending on the body part being imaged and whether contrast is used. Some complex studies like cardiac MRI may take 60-90 minutes. Patients must remain still during the scan for clear images. Including preparation and positioning, plan for approximately 90 minutes total appointment time.

What if I'm claustrophobic?

Claustrophobia affects 5-10% of MRI patients. Options include: open MRI machines (wider bore, less confined), mild sedation prescribed by your doctor, headphones with music or earplugs, keeping eyes closed during the scan, having a support person in the room, or practicing relaxation techniques. Tell your doctor about anxiety beforehand so they can help plan accommodations.

What is MRI with contrast?

MRI with contrast involves injecting a gadolinium-based contrast agent intravenously before or during the scan. This enhances visualization of blood vessels, inflammation, tumors, and certain abnormalities that might not be visible on a standard MRI. The contrast is generally eliminated from the body within 24 hours through the kidneys. It's different from CT contrast (iodine-based) and has fewer allergic reactions.

Why is an MRI so loud?

The loud knocking, thumping, and buzzing sounds during an MRI (up to 100 decibels, similar to a lawn mower) are caused by the rapid switching of magnetic field gradients. These gradient coils vibrate as electrical currents pass through them, similar to a loudspeaker. Patients are given earplugs or headphones to protect their hearing, and some facilities offer music during the scan.

MRI Scan — Magnetic Resonance Imaging Guide

🩺 About This Guide

This guide provides evidence-based information about MRI scans to help you prepare for your appointment and understand what to expect. Information is sourced from the American College of Radiology (ACR), RadiologyInfo.org, and peer-reviewed medical literature. Last reviewed: February 2026.

Overview

What is an MRI?

MRI (Magnetic Resonance Imaging) is an advanced diagnostic imaging technique that creates detailed pictures of organs, soft tissues, bone, and other internal body structures without using ionizing radiation. Instead, MRI uses:

1. A powerful magnetic field: Typically 1.5 to 3 Tesla (30,000 to 60,000 times stronger than Earth's magnetic field), which aligns hydrogen atoms in your body.

2. Radio waves: Pulses of radio frequency energy cause the aligned atoms to produce signals that vary depending on tissue type.

3. Computer processing: A computer analyzes these signals to create detailed cross-sectional or 3D images of the body.

MRI is particularly valuable for imaging the brain, spinal cord, nerves, muscles, ligaments, tendons, and blood vessels. It can detect tumors, inflammation, injury, infection, and degenerative conditions with exceptional clarity.

Types

Types of MRI Scans

Type	Description	Best For	Duration
Standard MRI	Traditional closed-bore scanner (60cm diameter)	Most diagnostic purposes, highest image quality	30-60 min
Open MRI	Open on sides, less confining	Claustrophobic patients, larger patients, children	45-90 min
Wide-Bore MRI	Larger diameter tube (70cm), shorter length	Balance of comfort and image quality	30-60 min
MRI with Contrast	IV gadolinium injection enhances certain tissues	Tumors, inflammation, blood vessels, infection	45-75 min
fMRI	Functional MRI measures brain activity	Brain mapping, neurological research, pre-surgical planning	60-90 min
Cardiac MRI	Specialized imaging of the heart	Heart structure, function, and blood flow	60-90 min

Open MRI typically produces lower resolution images than standard closed MRI. Your radiologist will recommend the best option based on your clinical needs.

Claustrophobia

Managing Anxiety and Claustrophobia

Claustrophobia affects 5-10% of patients undergoing MRI, but there are many effective strategies to help you complete your scan comfortably:

Before your appointment:

Tell your doctor about your anxiety — they can prescribe mild sedation (like lorazepam) to take before the scan
Ask about open MRI or wide-bore MRI options at your facility
Visit the imaging center beforehand to see the machine and meet the technologists
Practice relaxation techniques: deep breathing, visualization, or meditation

During the scan:

Keep your eyes closed throughout the procedure
Focus on breathing slowly and deeply
Listen to music through provided headphones (ask for your favorite genre)
Use the intercom to communicate with technologists anytime
Remember: the machine is open at both ends, and you can leave anytime
Some facilities allow a support person to stay in the room with you

💡 Helpful Tip

For feet-first scans (abdomen, pelvis, legs), your head stays outside or near the edge of the machine. Ask if your scan can be done feet-first — it's much easier for claustrophobic patients.

Preparation

How to Prepare for Your MRI

Metal and electronic devices: The MRI's magnetic field is extremely powerful. You must remove all metal objects before entering the scan room:

Jewelry, watches, piercings (including body piercings)
Hearing aids, glasses, removable dental work
Credit cards, phones, keys (magnetic fields will erase cards)
Hair clips, barrettes, wigs with metal clips
Underwire bras — wear a sports bra or the facility may provide a gown

Food and medications: Most MRI scans don't require fasting. However:

Abdominal or pelvic MRI may require 4-6 hours of fasting
Take your regular medications unless specifically instructed otherwise
If receiving contrast, drink plenty of water before and after

⚠️ Important: Disclose All Implants

You must inform staff about any implanted medical devices: Pacemakers, defibrillators, cochlear implants, insulin pumps, aneurysm clips, metal plates/screws/rods, artificial joints, stents, or any other implanted metal. Many modern implants are MRI-compatible, but verification is essential for your safety. Bring documentation about your implants if available.

The Procedure

What to Expect During Your MRI

Arrival and preparation (15-30 minutes):

Complete a safety questionnaire about implants and medical history
Change into a gown if needed and secure belongings in a locker
If receiving contrast, an IV line will be placed in your arm

During the scan (30-60 minutes typically):

You'll lie on a motorized table that slides into the MRI machine
The technologist will position coils (special devices that improve image quality) around the body part being scanned
You'll be given earplugs or headphones — the machine is loud (clicking, thumping, buzzing)
You must remain very still during sequences (movement blurs images)
Scans run in sequences of 2-15 minutes each, with brief pauses between
The technologist watches you through a window and communicates via intercom
You'll have a squeeze ball or button to signal if you need to stop

After the scan:

Most patients can resume normal activities immediately
If sedated, you'll need someone to drive you home
If you received contrast, drink extra fluids to help flush it from your system
Results are typically available within 24-48 hours

Safety

MRI Safety Information

MRI is considered very safe when proper screening procedures are followed. Key safety considerations include:

Contraindications (you may not be able to have an MRI if you have):

Certain cardiac pacemakers or defibrillators (many newer ones are MRI-compatible)
Cochlear implants (some are now MRI-compatible under specific conditions)
Certain types of aneurysm clips in the brain
Metal fragments in the eyes (from welding or metalworking)
Some types of insulin pumps and drug infusion devices

Contrast agent safety: Gadolinium-based contrast agents are generally very safe but:

Allergic reactions are rare (1-2 per 1000 patients) and usually mild
Patients with severe kidney disease (GFR <30) should avoid gadolinium due to risk of nephrogenic systemic fibrosis (NSF)
Pregnant patients: MRI without contrast is generally considered safe when medically necessary; contrast is avoided unless essential

🔬 No Radiation Exposure

Unlike X-rays, CT scans, and PET scans, MRI does not use ionizing radiation. This makes it safe for repeated scans and particularly suitable for children, pregnant women (when clinically needed), and patients requiring long-term monitoring.

Common Uses

What Conditions Can MRI Detect?

MRI is particularly valuable for diagnosing a wide range of conditions:

Brain and spine: Tumors, stroke, multiple sclerosis, Alzheimer's disease, aneurysms, spinal cord injuries, herniated discs, infections

Musculoskeletal: Torn ligaments (ACL, rotator cuff), cartilage damage, tendon injuries, bone infections, sports injuries, arthritis, bone tumors

Cardiovascular: Heart muscle damage, congenital heart defects, aortic aneurysms, blood vessel abnormalities

Abdominal: Liver disease, kidney problems, pancreatic conditions, inflammatory bowel disease

Breast: Breast cancer screening (for high-risk patients), evaluating cancer extent, monitoring treatment response

Pelvic: Prostate cancer, uterine fibroids, ovarian conditions, bladder abnormalities

Medical Information Reviewed: February 2026 · Sources include American College of Radiology (ACR), RadiologyInfo.org, and peer-reviewed medical literature.