Lumbar MRI scan

Definition

A lumbar magnetic resonance imaging (MRI) scan uses energy from strong magnets to create pictures of the lower part of the spine (lumbar spine).

An MRI does not use radiation (x-rays).

Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces many images.

Related exams include:

• Cervical MRI scan (neck MRI)
• MRI

Alternative Names

Magnetic resonance imaging - lumbar spine; MRI - lower back

How the Test is Performed

You will wear a hospital gown or clothes without metal snaps or zippers (such as sweatpants and a t-shirt). Make sure you take off your watch, jewelry and watches. Some types of metal can cause blurry images.

You will lie on a narrow table that slides into a large tunnel-like tube.

Some exams require a special dye (contrast). Most of the time, you will get the dye through a vein (IV) in your hand or arm before the test. You can also get the dye through an injection. The dye helps the radiologist see certain areas more clearly.

During the MRI, the person who operates the machine will watch you from another room. The test most often lasts 30 to 60 minutes, but may take longer.

How to Prepare for the Test

You may be asked not to eat or drink anything for 4 to 6 hours before the scan.

Tell your health care provider if you are afraid of closed spaces (have claustrophobia). You may be given a medicine to help you feel sleepy and less anxious. Your provider may suggest an "open" MRI, in which the machine is not as close to the body.

Before the test, tell your provider if you have:

• Brain aneurysm clips
• Certain types of artificial heart valves
• Heart defibrillator or pacemaker
• Inner ear (cochlear) implants
• Kidney disease or dialysis (you may not be able to receive contrast)
• Recently placed artificial joints
• Certain types of vascular stents
• Worked with sheet metal in the past (you may need tests to check for metal pieces in your eyes)

Because the MRI contains strong magnets, metal objects are not allowed into the room with the MRI scanner:

• Pens, pocketknives, and eyeglasses may fly across the room.
• Items such as jewelry, watches, credit cards, and hearing aids can be damaged.
• Pins, hairpins, metal zippers, and similar metallic items can distort the images.
• Removable dental work should be taken out just before the scan.

How the Test will Feel

An MRI exam causes no pain. You will need to lie still as too much movement can blur MRI images and cause errors.

The table may be hard or cold, but you can ask for a blanket or pillow. The machine makes loud thumping and humming noises when turned on. You can wear ear plugs to help block out the noise.

An intercom in the room lets you to speak to someone at any time. Some MRIs have televisions and special headphones that you can use to help the time pass.

There is no recovery time, unless you were given a medicine to relax. After an MRI scan, you can return to your normal diet, activity, and medicines.

Why the Test is Performed

You may need a lumbar MRI if you have:

• Low back or pelvic pain that does not get better after treatment
• Leg weakness, numbness, or other symptoms that do not improve or get worse

Your provider may also order a lumbar MRI if you have:

• Back pain and fever
• Birth defects of the lower spine
• Injury or trauma to the lower spine
• Low back pain and a history or signs of cancer
• Multiple sclerosis
• Problems controlling or emptying your bladder
• Disk herniation

Normal Results

A normal result means your spine and nearby nerves look OK.

What Abnormal Results Mean

Most of the time, abnormal results are due to:

• Herniated or "slipped" disk (lumbar radiculopathy)
• Narrowing of the spinal column (spinal stenosis)
• Abnormal wearing on the bones and cartilage in the spine (spondylitis)

Other abnormal results may be due to:

• Degenerative changes due to age
• Ankylosing spondylitis, a type of arthritis
• Bone infection
• Cauda equina syndrome
• Fractures of the lower back due to osteoporosis
• Disk inflammation (diskitis)
• Spinal cord abscess
• Spinal cord injury
• Spinal tumor
• Syringomyelia

Talk to your provider about your questions and concerns.

Risks

MRI contains no radiation. There have been no reported side effects from the magnetic fields and radio waves.

It is also safe to have MRI performed during pregnancy. No side effects or complications have been proven.

The most common type of contrast (dye) used is gadolinium. It is very safe. Allergic reactions to this dye are rare. However, gadolinium can be harmful to people with kidney problems that need dialysis. If you have kidney problems, please tell your provider before the test.

The strong magnetic fields created during an MRI can cause heart pacemakers and other implants to not work as well. It can also cause other pieces of metal inside your body to move or shift. For safety reasons, please do not bring anything that contains metal into the scanner room.

References

Chou R, Qaseem A, Owens DK, Shekelle P; Clinical Guidelines Committee of the American College of Physicians. Diagnostic imaging for low back pain: advice for high-value health care from the American College of Physicians. Ann Intern Med. 2011;154(3):181-189. PMID: 21282698 www.ncbi.nlm.nih.gov/pubmed/21282698.

Curry BP, Rosner MK. Evaluation and treatment of lumbar disk disease. In: Winn HR, ed. Youmans and Winn Neurological Surgery. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 286.

Gardocki RJ, Park AL. Degenerative disorders of the thoracic and lumbar spine. In: Azar FM, Beaty JH, Canale ST, eds. Campbell's Operative Orthopaedics. 13th ed. Philadelphia, PA: Elsevier; 2017:chap 39.

Sayah A, Berkowitz F. Head and spine imaging. In: Miller MD, Thompson SR, eds. DeLee and Drez's Orthopaedic Sports Medicine. 4th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 124.

Wilkinson ID, Graves MJ. Magnetic resonance imaging. In: Adam A, Dixon AK, Gillard JH, Schaefer-Prokop CM, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 6th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2015:chap 5.