Should I have a magnetic resonance image (MRI) scan for low back pain?
Introduction
This information will help you understand your choices, whether you share in the decision-making process or rely on your doctor's recommendation.
Key points in making your decision
Consider the following when making your decision about having a magnetic resonance image (MRI) scan:
- There is a good chance that your new (acute) low back pain will improve within 6 weeks—most cases do.
- Imaging tests for acute low back pain usually provide no helpful early information. Unless you have signs of a serious medical condition (such as spinal infection or bone cancer), avoid imaging tests except when you have low back pain that has persisted at least 4 weeks of home treatment, such as using non-steroidal anti-inflammatory drugs (NSAIDs) and avoiding activities that cause low back pain.1
- MRI is the best test for showing a herniated disc, soft-tissue damage, tumour, or infection.2 MRI also has the advantage of not using the ionizing radiation that the CT scan does. However, access to MRI scanners is not available in all areas; if you need an MRI scan, you may need to travel to a regional centre.
- Your doctor will probably wait to order an MRI for nerve-related symptoms that don't go away within at least 4 weeks, because these symptoms often go away on their own.
- A technique called rapid MRI is probably no better than a standard X-ray for diagnosing the cause of back pain or deciding what treatment to use.3
Medical Information
What is low back pain, and what causes it?
Strained muscles and ligaments are the most common cause of low back pain and stiffness. This type of low back trouble generally goes away after 4 to 6 weeks of non-surgical treatment.
Pressure on a spinal nerve can cause sciatica
symptoms, including back pain and/or leg numbness, pain, tingling, weakness, or loss of reflexes. Causes of sciatica include:
- Herniated disc, which usually gets better within a month or two.
- Arthritis.
- Spinal stenosis.
Other serious causes of back pain, such as infection, a tumour, or cancer, are rare. Only about 5% of low back pain cases are caused by serious disease or cause nerve-related problems that could be corrected with surgery. Imaging is helpful for diagnosing and planning treatment for these types of conditions.1
What are the risks of not treating low back pain?
We very often don't know what causes low back pain and, fortunately, it usually goes away on its own. But sometimes back pain is a sign of tight or weak muscles, poor posture, stress, or being overweight. It can also be a symptom of another condition, such as infection, a tumour, or a problem such as a herniated disc or spinal stenosis. If your back pain is caused by one or more of these problems and you don't take care of it, you could be in for more low back pain, decreased function, or other health problems in the future.
If your pain hasn't begun to subside after a couple of days of home treatment, see your doctor. After doing a health history and physical examination for low back pain, your doctor can recommend treatment, possibly including some physiotherapy. You probably won't have any imaging tests unless your doctor sees signs of a serious condition or nerve problems.
What types of problems can a magnetic resonance image (MRI) scan find?
An MRI is not a standard test for finding the cause of low back pain. As we age, we all develop changes in our spines that appear "abnormal" on an MRI , but in most people these changes don't cause symptoms.4 A complete medical history and physical examination are enough to diagnose and treat most low back pain.
Generally, an MRI is best used when your doctor suspects a specific problem after completing your medical history and physical examination. An MRI can:
- Detect problems of the spinal discs, such as a ruptured disc. The test will also help determine whether a disc is pressing on a nerve.
- Detect areas of the spinal canal that are abnormally narrowed (spinal stenosis).
- Detect tumours of the spinal cord. The tumours that most commonly spread to the spine include those from prostate, breast, or lung cancer.
- Further evaluate areas of joint inflammation (arthritis) or abnormal bone loss discovered during an X-ray test or a bone scan.
- Locate areas of the spinal cord that are not receiving an adequate blood supply.
- Detect areas of infection within the outermost layer of the spine and the spinal cord.
- Detect areas of nerve damage in the spinal cord caused by trauma or disease, such as multiple sclerosis.
- Evaluate spinal problems that have been present since birth (congenital).
For an idea of one type of problem an MRI can help identify, see MRI images of the lumbar spine
MRI alone may not accurately show the source of your pain. Over time, we all develop changes in our spines that appear "abnormal" on an MRI, though these changes don't necessarily cause symptoms.4 Before you make a decision to have a surgery, it is important that your symptoms, physical examination, and imaging studies all point to the same source of back or leg pain.
If you need more information, see the topic Low Back Pain.
Your Information
Your choices are:
- Have a magnetic resonance image (MRI) scan.
- Don't have a magnetic resonance image (MRI) scan.
The decision whether to have an MRI scan takes into account your personal feelings and the medical facts.
Deciding about having an MRI Reasons to have an MRI scan Reasons to not have an MRI scan
- You are looking for the cause of severe, persistent sciatica (causing severe pain, numbness, tingling, weakness, or loss of reflexes in your leg).
- Your doctor suspects that you may have some other problem (such as spinal infection or cancer) that is causing your symptoms.
- You have severe, persistent, and disabling back or leg symptoms, so continued non-surgical treatment may not be a reasonable option.
- Your doctor is planning surgery for a herniated disc and needs to see the disc clearly. For more information, see:
Are there other reasons you might want to have an MRI scan?
- You have not tried at least 4 weeks of non-surgical treatment (including ice, exercises, and monitoring your body mechanics).
- Your health history and physical examination revealed no signs of disease or nerve problems.
- You have pain but are not disabled by it, and are learning to manage your back pain by strengthening your abdomen and back muscles and using home treatment measures.
- Other imaging tests provide as accurate a screening for your particular situation as MRI does and may be more accessible and less expensive.
- You are not willing to have a surgical procedure.
Are there other reasons you might not want to have an MRI scan?
These personal stories may help you make your decision.
Wise Health Decision
Use this worksheet to help you make your decision. After completing it, you should have a better idea of how you feel about whether you should have a magnetic resonance image (MRI) scan. Discuss the worksheet with your health professional.
Circle the answer that best applies to you.
I have already had a thorough physical examination. Yes No Unsure I have tried ice, exercises, and healthy back practises for at least 4 weeks. Yes No NA* I have severe, disabling sciatica symptoms, and MRI results would help me make treatment decisions. Yes No Unsure My doctor wants to check me for infection or cancer. Yes No Unsure I am planning on having disc surgery, and the MRI results are needed for surgery planning. Yes No Unsure Another imaging test can provide the information my doctor needs at less cost. Yes No Unsure I have the financial resources or health insurance coverage to cover the cost of an MRI. Yes No Unsure *NA=Not applicable
Use the following space to list any other important concerns you have about this decision.
What is your overall impression?
Your answers in the above worksheet are meant to give you a general idea of where you stand on this decision. You may have one overriding reason to have or not have an MRI to learn more about your low back pain.
Check the box below that represents your overall impression about your decision.
Leaning toward having an MRI
Leaning toward NOT having an MRI
Return to the topic:
Other Places To Get Help
Organization
Canadian Orthopaedic Association 4150 St. Catherine Street West Suite 360 Westmount, QC H3Z 1P4 Phone: (514) 874-9003 Fax: (514) 874-0464 Web Address: http://www.coa-aco.org
| Author: | Douglas Dana Shannon Erstad, MBA/MPH | Last Updated: April 3, 2006 |
| Medical Review: | William M. Green, MD - Emergency Medicine Tom Bailey, MD - Family Medicine Kathie Hummel-Berry, PT, PhD - Physical Therapy Robert B. Keller, MD - Orthopedics | |
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