Contribution of MR to depicting of cranio-cervical junction of patients with chronic poly-arthritis

Involvement of the cranio-cervical junction is a dangerous and not a rare complication in chronic poly-arthritis. Atlantoaxial subluxation is a common presentation and this can be assessed by plain X-ray of the cervical spine. MR enables to depict the atlantoaxial subluxation as well as compressive myelopathy and its cause. By comparing the signal intensity before and after contrast medium injection we are able to differentiate acute succulent and chronic pannus, effusion and bone. Patients with unstable atlantoaxial subluxation and patients with progressive myelopathy are candidates for surgery. Posterior element fusion C0-C2 is a method of choice, and the wires in this area do not cause a significant problem in assessing the volume reduction of the periodontoid pannus. MR is also useful method for monitoring the local finding in the cranio-cervical junction during conservative treatment. (authors)