Diagnosis

Magnetic Resonance Imaging (MRI).Magnetic resonance imaging (MRI) can provide very well-defined images of soft tissue and bone. It is not painful, but some people may feel claustrophobic in scanners that are fully enclosed. MRIs can detect annular tears, or disk fragments, and non-spinal causes of back pain, including infection and cancer. However, MRIs are no more effective than x-rays in identifying arthritis, and they are more expensive. Some medical evidence suggests that relying on MRI images of disk abnormalities to determine treatment has resulted in many unnecessary surgeries. At least 40% of all adults have bulging or protruding vertebral disks, and most have no back pain. The degree of disk abnormalities revealed by MRIs often have very little to do with the severity of the pain or the need for surgery. Disk abnormalities in people who have back pain may simply be a coincidence rather than an indication for treatment.

Click the icon to see an image of a MRI machine.

Advanced imaging techniques should be used only when underlying infection, cancer, or nerve involvement is suspected.

Magnetic Resonance Neurography. This imaging exam looks at the nerves in the pelvic area. Researchers reporting in the Journal of Neurosurgery found that it helped reveal pinched nerves that can cause leg pain. The findings could lead to new ways to diagnose sciatica and piriformis syndrome.

Bone Scintigraphy and SPECT Imaging.In rare cases, doctors may use bone scintigraphy (bone scanning) to determine abnormalities in the bones. The technique may be useful for early detection of spinal fractures, cancer that has spread to the bone, or osteoarthritis. During this exam, a small amount of radioactive material is injected into a vein. It circulates through the body, and is absorbed by the bones. The bones can then be visualized using x-rays or single photon emission computed tomography (SPECT). A study in the February 2006 journal Radiology found that SPECT can help determine which patients would get low back pain relief from spinal injections. Forty-seven patients were randomly divided into two groups: One group received SPECT before they were scheduled for an injection, the other group did not. Those who showed spinal problems on the SPECT images received an injection in the area of the abnormalities. Those who had a normal SPECT, as well as those who did not have the test at all, received injections in the area recommended by their referring physician. After a month, those who had targeted injections using the SPECT images had greater pain relieve than those who did not.