MRI and low back pain

Back pain and sciatica are among the most common health complaints. Almost everyone will have back pain at some time in their life. Most of the time, the exact cause of the pain cannot be found.

An MRI scan is an imaging test that can create detailed pictures of the spine. This article focuses on MRI scans to evaluate low back pain.



Both you and your doctor will often be worried that something serious may be causing your low back pain. Could your pain be caused by cancer or infection in your spine? How does your doctor know for sure?

You will likely need an MRI right away if you have warning signs of a more serious cause of back pain:

  • Cannot pass urine or stools
  • Cannot control your urine or stools
  • Difficulty with walking and balance
  • Back pain that is severe in children
  • Fever
  • History of cancer
  • Other signs or symptoms of cancer
  • Recent serious fall or injury
  • Back pain that is very severe, and not even pain pills from your doctor help
  • One leg feels numb or weak and it is getting worse

If you have low back pain but none of the warning signs mentioned about, research shows that getting an MRI does NOT lead to better treatment, better pain relief, or a quicker return to activities.

You and your doctor may want to wait before ordering an MRI. If the pain does not get better or becomes worse, then you doctor will likely order one.


  • Most of the time, back and neck pain is not caused by a serious medical problem or injury.
  • Low back or neck pain often gets better on its own.

MRI and CT scans create detailed pictures of your spine. It can pick up most injuries that you have had in your spine. As a result they often find small problems or changes that are not the cause of your current back pain. These findings will rarely change how your doctor first treats you.

However, small problems or changes seen on MRI scan can lead to:

  • Your doctor ordering more tests that you may not really need.
  • Worrying more about your health and your back even more. If these worries cause you to not exercise, this may can cause your back to take longer to heal.


Contrast (dye) used with MRI scans can rarely cause severe allergic reactions or damage to your kidneys.

The strong magnetic fields created during an MRI can cause heart pacemakers and other implants to not work as well. It can also cause a piece of metal inside your body to move or shift. Tell your health care providers about any metal objects that you may have on your body.


Chou R, Qaseem A, Owens DK, Shekelle P; for the 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 Feb 1;154(3):181-189.

Update Date: 4/8/2011 12:00:00 AM

Reviewed by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc; C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery.

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