Quick answer: a lumbar spine MRI takes detailed pictures of your lower back, including the vertebrae, discs, spinal nerves and surrounding tissues, without radiation. It is the most sensitive imaging test for the spine and is often used to find the cause of back pain or sciatica. It usually takes 30 to 60 minutes, or about 45 to 80 minutes with contrast. You lie on your back on a padded table, and the hardest part is staying still if you are in pain, so tell the technologist before you start.
Most of the patients I scan for lower back MRIs arrive in pain, and many are worried they will not be able to lie still. With good positioning, almost everyone can. Here is what the test shows and how it goes.
What does a lumbar spine MRI show?
MRI is the best available method to see the spinal cord and nerves, and it shows discs, ligaments and soft tissues more clearly than other imaging. A lumbar MRI can help assess or detect:
- disc and joint disease, frequent causes of lower back pain and sciatica (pain that radiates down the leg)
- compression or inflammation of the spinal nerves or the lower end of the spinal cord
- injuries to bones, discs or ligaments after trauma
- infection of the vertebrae, discs or the coverings of the nerves
- tumors in the vertebrae, nerves or nearby soft tissues
- compression fractures and bone swelling
- alignment of the spine and birth defects of the vertebrae
- changes after surgery, such as scarring, infection or a recurring herniated disc
Doctors also use it to plan treatments such as surgery to relieve a pinched nerve, spinal fusion or steroid injections.
For some fractures, a CT scan may show the bone better than MRI. See [link: CT Scan vs MRI].
Lumbar MRI with or without contrast?
Most lumbar MRIs for back pain are done without contrast. Contrast (gadolinium through an IV) is more often added when the doctor is looking for infection, tumors or inflammation, or after previous back surgery, to help tell scar tissue from a recurring disc. With contrast, the exam usually takes longer. See [link: MRI With vs Without Contrast].
How to prepare
- Food, drink and medications: usually no restrictions. Take your pain medication as prescribed: being comfortable helps you stay still.
- Implants: tell the team about any spinal implants, rods or screws, and especially about spinal cord stimulators or pain pumps, which need special checks. See [link: Can You Have an MRI With Metal Implants, Tattoos or a Pacemaker?].
- Clothing: athletic wear and back braces can contain metallic threads; expect to change into a gown.
- If you have severe pain: tell your doctor in advance. If you know you cannot lie flat for half an hour, ask about pain relief before the scan.
- Pregnancy and breastfeeding: tell the team. Contrast is generally avoided in pregnancy; for breastfeeding, the American College of Radiology reports that the amount of contrast reaching the baby is extremely low.
The full checklist is in [link: How to Prepare for an MRI].
What the scan feels like
- Positioning. You lie on your back on a padded table. The coil that captures the images is usually built into the table under your lower back. A cushion under your knees often makes lying flat much more comfortable for the back.
- Going in. Depending on the scanner, you may go in head first or feet first. Because the scan is centered on your lower back, your head is often nearer the opening than in a brain MRI.
- Hearing protection. You get earplugs or headphones.
- Staying still. Each sequence lasts from under a minute to several minutes. Small movements of the hips or legs blur the images of the lower spine.
- Contrast, if needed, is injected partway through.
From the scanner room: [TU EXPERIENCIA: cómo colocas a un paciente con dolor lumbar o ciática para que aguante: cojines, posición de las piernas, qué le dices antes de empezar, qué hacer si el dolor aparece a mitad de la prueba.]
How long does a lumbar MRI take?
Usually 30 to 60 minutes, and about 45 to 80 minutes with contrast. Plan extra time for check-in and changing. More in [link: How Long Does an MRI Take?].
Risks and limitations
- Very low risk when safety screening is followed.
- Spinal hardware from previous surgery is usually not a safety problem but can blur the images near it.
- Contrast: allergic reactions are rare and usually mild; tiny amounts of gadolinium can remain in the body after multiple contrast scans, with no known health effects.
- Movement: severe pain or anxiety can make it hard to stay still, which lowers image quality.
- Size: very large patients may need a specialized scanner; call ahead if this concerns you.
Understanding your lumbar MRI report
A radiologist reviews the images and sends a signed report to your doctor, who will explain the results. Lumbar reports often mention terms like disc bulge, disc herniation, degeneration, stenosis or facet arthropathy. These findings are very common, including in many adults who have no back pain at all. The report describes what the images show; your doctor decides whether a finding explains your symptoms.
Tips from the technologist
[TU EXPERIENCIA: 3-4 consejos propios. Ideas: tomar la analgesia a su hora, ir al baño antes, avisar si no aguantas tumbado antes de empezar y no a mitad, respirar con calma durante las secuencias.]
Frequently asked questions
Will a lumbar MRI show a herniated disc?
Yes. MRI is the best test to see discs and whether they press on the spinal nerves.
Is my head inside the machine for a lumbar MRI?
Usually less than in a brain MRI, because the scan is centered on your lower back. Depending on the scanner and your height, your head may be inside the tube or near the opening.
Can I have a lumbar MRI if I have screws or rods in my spine?
In most cases, yes. Tell the team about the surgery; the hardware may distort images close to it.
Do I need a lumbar MRI for back pain?
That is your doctor’s decision. Many episodes of lower back pain improve without imaging, and MRI is usually reserved for specific situations. Ask your doctor what the scan will change in your care.
How much does a lumbar MRI cost?
It depends on your insurance and where you have it done. See [link: How Much Does an MRI Cost Without Insurance?].
This article is for general information and does not replace advice from your doctor or imaging team.