What Is an MRI Scan? Procedure, Uses & Risks

If your doctor has recommended an MRI scan, you might be wondering: What is it? Why do I need one? Is it safe? Don’t worry—you’re not alone. Many people feel a little nervous when they hear the term Magnetic Resonance Imaging (MRI). But the truth is, an MRI is one of the most advanced, non-invasive imaging techniques in modern medicine, helping doctors see what’s going on inside your body—without using harmful radiation.

In this guide, we’ll break down what an MRI scan is, how the procedure works, its common uses, risks, safety aspects, and key facts you should know. Let’s dive in.

What Is an MRI Scan?

An MRI scan (Magnetic Resonance Imaging) is a medical imaging technique that uses a strong magnetic field and radio waves to create detailed, cross-sectional pictures of the body. Unlike X-rays or CT scans, MRI doesn’t use ionizing radiation, making it a safer option for many patients.

It’s particularly useful for looking at soft tissues—like the brain, spinal cord, muscles, joints, and organs—which are harder to see with other imaging methods.

How Does an MRI Work?

Think of an MRI machine as a giant magnet shaped like a tunnel. When you lie inside:

1. The magnetic field temporarily aligns hydrogen atoms in your body.
2. Radio waves then disturb this alignment.
3. As the atoms return to normal, they send out signals.
4. The MRI computer converts those signals into detailed images of your body’s internal structures.

This process is completely painless and does not harm your body.

What Happens During an MRI Scan? (Procedure)

If you’ve never had an MRI before, here’s what to expect:

• Preparation: You may be asked to change into a gown and remove any metal objects (jewelry, belts, watches).
• Positioning: You’ll lie flat on a sliding table that moves into the MRI machine.
• During the scan:
  • You’ll hear loud banging or tapping noises—earplugs or headphones are usually provided.
  • The scan can take 15 minutes to over an hour, depending on the body part being imaged.
  • It’s important to stay still for clear images.
• Contrast dye (gadolinium): In some cases, a contrast agent is injected to highlight certain areas like blood vessels or tumors.
• After the scan: There’s no recovery time needed—you can usually go about your day as normal.

Some facilities also offer open MRI machines, which are less confining and can be helpful for people with claustrophobia.

What Is an MRI Scan Used For?

MRI is an incredibly versatile tool and is used in diagnosing and monitoring a wide range of conditions:

• Brain and Nervous System: Stroke diagnosis, multiple sclerosis, brain tumors, neurological disorders.
• Spinal Cord: Detecting slipped discs, spinal injuries, or infections.
• Joints & Musculoskeletal: Sports injuries, ligament tears, arthritis, bone infections.
• Heart & Blood Vessels (Cardiac MRI): Identifying heart disease, blocked blood vessels, or congenital defects.
• Abdomen & Pelvis: Detecting liver disease, kidney problems, uterine or ovarian issues.
• Cancer: Locating tumors, measuring their size, and tracking treatment progress.

MRI vs CT Scan: What’s the Difference?

Both MRI and CT scans provide detailed images, but they differ in technology:

• CT scans use X-rays (radiation) → faster and better for bone injuries or emergencies.
• MRI scans use magnetic fields & radio waves → better for soft tissues, brain, spinal cord, and organs.

Risks & Safety of MRI

One of the biggest advantages of MRI is safety—since there’s no radiation exposure. However, there are some precautions:

• Metal implants: People with pacemakers, cochlear implants, aneurysm clips, or certain surgical implants may not be eligible.
• Contrast dye risks: Rarely, patients may have an allergic reaction or kidney issues.
• Claustrophobia: Some people feel anxious inside the machine, but sedation or open MRI options can help.
• Pregnancy: Generally considered safe, but contrast dye is avoided unless absolutely necessary.

Overall, MRI scans are safe and well-tolerated by most patients.

Key Facts About MRI Scans

• MRI was first used in medicine in the 1970s.
• More than 40 million MRI scans are performed every year worldwide.
• Unlike X-rays and CT, MRI uses no ionizing radiation.
• MRI images are interpreted by a radiologist, who provides a detailed report to your doctor.
• World Health Organization (WHO) and National Institutes of Health (NIH) recognize MRI as one of the safest diagnostic imaging tools.
• The American College of Radiology (ACR) provides safety guidelines for MRI use.

Why MRI Matters in Modern Healthcare

MRI isn’t just about diagnosis—it’s about early detection, better treatment planning, and improved outcomes. From identifying a small tumor before it spreads to evaluating a torn ligament, MRI gives doctors the clarity they need to provide the best care.

Take the Next Step: Molecular Diagnostics

While MRI scans show doctors what’s happening structurally, molecular diagnostic tests go even deeper by analyzing genes, proteins, and molecules. Together, imaging and molecular diagnostics provide a complete picture of your health—helping to detect diseases earlier, personalize treatments, and improve outcomes.

If you’re considering advanced testing alongside your MRI scan, ask your healthcare provider about molecular diagnostic options available at certified laboratories.

Final Word: MRI scans are safe, effective, and a cornerstone of modern medicine. They help doctors see what the human eye cannot, guiding better decisions for your health.

Common FAQs About MRI Scans

Is an MRI scan painful?

No, MRI scans are painless. The only discomfort may come from lying still or the loud noise.

How long does an MRI scan take?

Depending on the body part, it usually takes 15–60 minutes.

Can you eat before an MRI scan?

In most cases, yes. But if contrast dye is used, you may be asked to fast for a few hours.

Is MRI safe for kids?

Yes, MRI is safe for children and often used to diagnose pediatric conditions.

Can you get an MRI if you have metal in your body?

It depends—pacemakers, cochlear implants, and some surgical clips may make MRI unsafe.

Why is MRI so loud?

The banging sounds come from the machine’s magnets rapidly turning on and off.

Can you sleep during an MRI?

Yes, some people doze off if they are comfortable enough.

Is MRI better than CT?

MRI is better for soft tissues (brain, muscles, organs), while CT is better for bones and emergencies.

Can I get an MRI if I’m pregnant?

Yes, MRI is generally safe, but contrast dye is usually avoided.

How soon will I get my MRI results?

A radiologist reviews your images, and results are typically sent to your doctor within 1–2 days.