In patients with osteoarthritis, radiography may be useful in assessing the extent of joint damage, but the correlation between its findings and the patient's symptoms is surprisingly poor. In patients with chronic disease, repeat radiography is useful in assessing the progress of disease or the necessity for surgical intervention. Although magnetic resonance imaging and radionuclide bone scanning are powerful techniques for obtaining information about bones and joints, they should be used only when their results will be used to make important diagnostic or therapeutic decisions. As is true for plain radiography, myelography, and even autopsy, MRI of the spine often reveals abnormalities in people who do not have back pain. In one study, only 36 percent of patients free of back pain had normal findings on magnetic resonance imaging of the lumbar spine.
Bone scans are useful in detecting osteomyelitis, stress fractures, and metastases to bone.