Magnetic resonance imaging in rheumatic disorders of the spine and sacroiliac joints.

OBJECTIVE: To review the value of magnetic resonance imaging (MRI) in diagnosis and evaluation of rheumatic diseases of the spine and sacroiliac joints.
METHODS: A review of the literature on MRI of the spine and sacroiliac joints in rheumatoid arthritis (RA), ankylosing spondylitis (AS), infectious spondylodiscitis, infection of the sacroiliac joint (SIJ), gout, calcium pyrophosphate deposition disease, nontraumatic vertebral compression fractures, insufficiency fracture of the sacrum, avascular necrosis of the vertebral body, sarcoidosis, and Paget's disease was performed. The reports were obtained from a Medline search.
RESULTS: In RA, AS, and crystal deposition disease, synovial tissue, atlantoaxial and subaxial subluxations, crystal deposition, and neurologic compromise can be adequately diagnosed with MRI of the cervical spine. Studies on MRI of SIJs in AS indicate that MRI enables early diagnosis of sacroiliitis. In most cases of infectious spondylodiscitis, avascular necrosis of the vertebral body, nontraumatic vertebral compression fractures, and insufficiency fractures of the sacrum characteristic findings on MRI suggest the correct diagnosis. Moreover, soft tissue abnormalities and neurologic compromise can be visualized. In infection of the SIJ, MRI shows findings suggesting an inflammatory process. In Paget's disease, MRI does not provide additional information as compared with plain radiography (PR) or computed tomography (CT).
CONCLUSION: In evaluation of spinal and SIJ abnormalities in many rheumatic diseases, MRI, in addition to PR, can replace conventional tomography, CT, and myelography. Moreover, MRI can visualize soft tissue abnormalities and neurologic compromise without use of intrathecal contrast.