What Is an MRI Scan Used to Diagnose? Conditions It Can Find
Updated: Oct 29
An MRI scan helps doctors find and understand problems in the brain, spine, joints, muscles, organs, and blood vessels. It is especially good at showing soft tissue, so it is often used for nerve problems, sports injuries, back pain, and some cancers. This guide walks through the main conditions an MRI can help diagnose, what it can't do, and what to expect if your doctor orders one.
How an MRI helps with diagnosis
MRI stands for magnetic resonance imaging. It uses a strong magnet and radio waves, not X-rays, to make detailed pictures of the inside of your body. Because there is no ionizing radiation, MRI can be repeated over time when a doctor needs to track a condition.
The big strength of MRI is soft tissue. It can show the difference between healthy tissue and swelling, tears, scar tissue, or abnormal growths. Many of these things are hard to see on a regular X-ray. New to MRI? Start with our guide on what an MRI is and how it works.
Brain and nervous system conditions
MRI is one of the main tools doctors use to look at the brain and nerves. It can help find or check on:
Brain tumors: showing their size and location
Multiple sclerosis (MS): finding the spots, called lesions, that are typical of MS and tracking them over time
Stroke: showing areas of the brain affected by a stroke
Aneurysms and blood vessel problems: bulges or other changes in the blood vessels of the brain
Seizures: looking for changes in the brain that may be linked to seizures
Head injuries: checking for injury to the brain tissue
To learn how to read common terms on a brain report, see our guide to brain MRI terms.
Spine conditions
Back and neck pain are some of the most common reasons for an MRI. A spine MRI can help show:
Herniated or bulging discs: discs that push out and may press on nerves
Spinal stenosis: narrowing of the space around the spinal cord or nerves
Degenerative disc disease: wear and tear of the spinal discs
Spinal cord injury: damage to the cord after an accident or fall
Tumors and infections: growths or infection in or near the spine
An MRI isn't always the first step for back pain. Read do you need an MRI for back pain? to learn when it tends to help.
Joint, muscle, and bone conditions
MRI shows ligaments, tendons, cartilage, and muscles in detail. That makes it useful for injuries and joint pain, including:
Ligament and tendon tears: such as an ACL tear in the knee or a rotator cuff tear in the shoulder
Cartilage and meniscus damage: in the knee, hip, shoulder, and other joints
Muscle strains and tears: especially when pain doesn't improve
Arthritis: changes in the joint and surrounding tissue
Bone problems: bone infection (osteomyelitis), bone bruises, and some fractures that don't show on X-ray
Soft tissue lumps: masses in muscle or other soft tissue
For specific joints, see our guides on when to get an MRI for knee pain and MRI for a rotator cuff injury.
Head and neck conditions
MRI can also look at structures in the face, jaw, and neck, such as:
Jaw joint (TMJ) problems: the joint that connects your jaw to your skull
Sinus problems: in some cases, when a doctor needs more detail
Salivary gland problems: growths, swelling, or blockages
Growths in the head and neck: both cancerous and non-cancerous
Abdominal and pelvic conditions
MRI can give a detailed look at organs in the belly and pelvis. Doctors may use it to check:
Liver: tumors, scarring, and other liver conditions
Kidneys: growths and differences present from birth
Pancreas and bile ducts: inflammation, blockages, and growths
Uterus and ovaries: fibroids, cysts, and other growths
Prostate: helping doctors look for and evaluate prostate cancer
Learn more about prostate imaging in our guide on how to read a prostate MRI.
Heart and blood vessel conditions
A cardiac MRI shows the heart's structure and how well it pumps. It may be used to look at heart muscle damage, heart muscle disease, heart valve problems, heart defects present from birth, and inflammation around the heart. A related scan called MR angiography (MRA) focuses on blood vessels.
Breast conditions
Breast MRI is sometimes used along with mammograms. Doctors may order it to screen people at higher risk of breast cancer, to look at how far a known cancer has spread within the breast, or to check breast implants for leaks.
Can an MRI detect cancer?
MRI can help find many types of tumors, especially in soft tissue such as the brain, breast, prostate, and liver. It can show a tumor's size and location, and doctors often use follow-up MRIs to see how a tumor is responding to treatment. MRI can also help guide some biopsies.
But an MRI alone usually can't confirm cancer. A biopsy or other tests are often needed. If your scan shows something unclear, your doctor will explain the next steps.
What an MRI can't do
MRI is powerful, but it isn't the best test for everything.
It may miss some very small changes.
Some findings are "incidental," meaning they are found by chance and may not cause any problem.
For some emergencies, bleeding, or certain bone and lung problems, a CT scan or X-ray may be the better choice.
Your doctor picks the test that best answers the medical question. Our guide to MRI vs. CT vs. X-ray explains the differences.
Why the radiologist matters
The pictures are only part of the story. A radiologist, a doctor trained to read medical images, studies your MRI and writes a report for your doctor. At Millenium MRI, scans are read by board-certified radiologists, and results are usually sent to your referring doctor within 24 hours.
Frequently asked questions
Can an MRI show nerve damage?
An MRI can show things that press on or affect nerves, such as a herniated disc or narrowing in the spine. It can also show some changes in the nerves themselves. Your doctor may use other tests, such as nerve studies, along with MRI.
Can an MRI show inflammation?
Often, yes. MRI can show swelling and fluid in joints, tendons, bones, and other tissue. Read more in does an MRI show inflammation?
Will an MRI show everything wrong with me?
No. An MRI looks at the body part your doctor ordered. It answers a specific medical question and does not check for every possible problem.
Is an MRI safe for children?
For most children, yes. MRI does not use radiation. Parents can learn more in our pediatric MRI guide.
What if I'm claustrophobic?
Let your doctor and the MRI team know ahead of time. They can talk with you about ways to make the scan easier. See our tips on overcoming claustrophobia during an MRI.
Related reading
Schedule an MRI at Millenium MRI
Millenium MRI has centers in Ocala, Largo, and Tamarac, Florida, and in North Little Rock, Springdale, Jonesboro, and Marion, Arkansas. Our ARRT-certified technologists and board-certified radiologists help make your visit smooth. Same-day appointments are often available, and most patients are in and out in about 35 minutes. We accept most insurance plans, workers' compensation, personal injury cases, and self-pay, and our costs are lower than hospital imaging because of lower overhead. Call your nearest center or request an appointment online.
This article is for general information and is not medical advice. Talk with your doctor about your specific situation.
The explanation of how MRI uses magnetic fields and radiofrequency signals provides a useful introduction to the basic principles of medical imaging. Understanding the relationship between MRI physics and image formation is particularly important for anyone studying radiologic technology.