Do You Need An MRI For Back Pain?

spinal stenosis

Given the difficulty of diagnosing back pain, patients are often eager to try every available diagnostic method. There is a popular idea among pain patients that MRI scans are a necessary part of diagnosis. For many reasons, this is a misconception.

The MRI

Magnetic resonance imaging (MRI) scans use a large magnet to surround the patient with a magnetic field that excites the water molecules in his or her body. MRI films capture the image of these excited molecules and end up with an accurate, detailed picture of the patient's spinal anatomy. MRIs are more thorough than X-rays, which mainly show bones. MRIs show softer tissues, such as discs, nerves, muscles and ligaments as well as bones.

This kind of imaging test is a great advance in diagnostic science, allowing medical professionals to detect disc abnormalities, nerve obstruction, tumors and infections. However, for the typical back pain patient, MRIs may not be especially useful.

"Normal Abnormalities"

Some in the medical community have dubbed certain changes within the spine "normal abnormalities." This particularly applies to disc degeneration. Spinal discs wear with age and use. A variety of studies reporting the findings of spinal MRI scans have included people without back pain. Findings have varied, but disc degeneration was detected by scans in an average of about 30% of asymptomatic people. This means that an MRI may show a problem, but that the problem may not be causing your pain.

Uses

MRIs are very proficient at detecting disc and nerve abnormalities, but for most people, the cause of pain lies elsewhere. At least 80% of the population suffers from lower back pain at some point; for about 5%, the pain is caused by a disc problem with nerve impingement. MRIs also detect tumors and infections around the spine, but these are even rarer than nerve and disc problems. The type of pain you feel and the correlating symptoms you have should help to confirm or rule out discogenic pain, nerve impingement, spinal tumors or infections. Most commonly, the cause of back pain is muscle or ligament strain. This can take anywhere from days to a few months to heal with conservative treatment.

Cost

Nobody wants to sacrifice their health to save a few bucks, but the limited usefulness of the MRI combined with its cost can be taken together as reason enough not to rush into it. You can expect a scan to cost around $2,000, but much more or slightly less depending on where you live. Insurance companies don't always offer full reimbursements for MRIs.

MRIs are best reserved for people whose pain is not resolved by months of conservative treatment and those who immediately represent severe symptoms associated with nerve impingement, tumor or infection. If the medical professionals treating you don't order a scan right off the bat, it doesn't mean they aren't doing their jobs. If all they do is give you pain pills, however, it does mean they aren't doing their jobs. Diagnosis of back pain should involve a physical exam, questions about your medical history and, if no cause is apparent to the doctor, a trip to the physical therapist for a muscle balance check and to the chiropractor for alignment testing.

MRIs aren't needed by everyone, or even most people with back pain. As long as your doctor is taking other steps to understand the source of your pain, you don't need to rush the MRI.