The following general rules are usually considered by a physician before ordering an MRI scan for a patient with back pain, neck pain or leg pain stemming from a spine problem.
Indications for when to get an MRI scan include:
- After 4 to 6 weeks of leg pain, if the pain is severe enough to warrant surgery
- After 3 to 6 months of low back pain, if the pain is severe enough to warrant surgery
- If the back pain is accompanied by constitutional symptoms (such as loss of appetite, weight loss, fever, chills, shakes, or severe pain when at rest) that may indicate that the pain is due to a tumor or an infection
- For patients who may have lumbar spinal stenosis and are considering an epidural injection to alleviate painful symptoms
- For patients who have not done well after having back surgery, specifically if their pain symptoms do not get better after 4 to 6 weeks.
Contraindications for undergoing an MRI scan for spine-related pain in the back, neck or leg include:
- Patients who have a heart pacemaker may not have an MRI scan
- Patients who have a metallic foreign body (metal sliver) in their eye, or who have an aneurysm clip in their brain, cannot have an MRI scan since the magnetic field may dislodge the metal
- Patients with severe claustrophobia may not be able to tolerate an MRI scan, although more open scanners are now available, and medical sedation is available to make the test easier to tolerate
- Patients who have had metallic devices placed in their back (such as pedicle screws or anterior interbody cages) can have an MRI scan, but the resolution of the scan is often severely hampered by the metal device and the spine is not well imaged.
In regards to this last point, if stainless steel was used for the fusion, the artifact is much more of a problem than if titanium was used. Recently, titanium has been used for most fusions, and stainless steel has largely fallen out of favor because of the inability to get a postoperative MRI scan.
If a patient's symptoms match the indications for an MRI scan, and there are no known risk factors (contraindications), then an MRI scan can potentially be very beneficial in helping plan further back pain treatment.