Computed tomography and conventional radiographs of the craniocervical region in rheumatoid arthritis. A comparison.

Radiographs and computed tomography (CT) scans of 12 patients with rheumatoid arthritis of the cervical spine were reviewed to determine whether CT provides additional information to that obtained from conventional radiography and tomography. Modalities were compared with respect to determination of the extent of erosion, C1-C2 subluxation, atlantoaxial impaction, and soft tissue findings. CT showed greater extent of erosion in 9 of 12 patients. In 11 patients with C1-C2 subluxation, CT and plain radiographs were both useful because it was necessary to demonstrate both sagittal and axial relationships. In the 5 patients with atlantoaxial impaction both CT and plain radiographs demonstrated the abnormal relationships between the odontoid and the foramen magnum. CT showed attenuation of the transverse ligament and the presence or absence of spinal cord compression, whereas plain radiographs did not. Nevertheless, significant new information regarding the spinal cord was obtained by CT in only 1 of the 12 patients. Computed tomography provides additional information about the rheumatoid cervical spine that is unobtainable by conventional modalities. In particular, CT demonstrates bone changes in the axial projection and facilitates evaluation of soft tissue, ligament, and spinal cord involvement. However, CT should be reserved for those instances in which plain radiographs and tomograms do not explain clinical findings.