ATLANTO-EPISTROPHIC MRI INVOLVEMENT IN EARLY RHEUMATOID ARTHRITIS

Background: Rheumatoid arthritis (RA) is the most common inflammatory disorder of the cervical spine. Nevertheless involvement of the craniocervical junction as the presenting symptom of RA is a very rare feature. Cervical involvement progression has been correlated with peripheral disease activity and erosive disease. While conventional radiography allows the clear documentation of the late stages of inflammatory changes, MRI is sensitive to detect early inflammatory lesions. Objectives: The purpose of this study was to determine the incidence of atlo-axial involvement with unenhanced and Gadolinium-enhanced Magnetic Resonance Imaging (MRI) of the cervical spine in patients with early RA before the development of symptoms. To identify the predictors of atlo-axial synovitis, clinical and immunological data were correlated to MRI study of upper cervical spine. Methods: Twenty patients with early RA (17 females and 3 males with a mean age of 54.8±12.6 years and a mean disease duration of 6.5±3 months) who met the revised ACR criteria and with disease duration less than 1 year were included in the study. All patients showed an active rheumatoid arthritis at onset (DAS44>3,7). Rheumatoid factor (RF) was present in 13 patients (65%) and anti-CCP antibodies (anti-CCP) were present in 15 patients (75%). Radiographic damage of hands and feet was present in 55.0% of patients. No patient presented symptoms of cervical involvement. The patients underwent MRI study of upper cervical spine within 3 months from diagnosis. MR imaging was performed with a 1.5 superconductive magnet system using phased array coil. The protocol included fast SE T1w on sagittal plane and fast spin-echo T2 on axial and sagittal planes. FSPGR T1w with fat saturation on sagittal, axial and coronal planes after contrast medium was used. The presence of pannus tissue at MR images was considered an active synovitis. Results: Five out of the twenty patients (25%) presented a cranio-cervical involvement with active synovitis at MRI. Patients with cervical involvement presented an higher levels of ESR (74.8±16.0) at onset compared to patient without cervical synovitis (34.1±24),(p=0.005), an higher swollen joint count (14.8±7.0) vs (8.5±5.0),(p=0.02), and an higher DAS44 level (5.2±0.8) vs (3.9±0.2),(p=0.03), respectively. All the patients with active synovitis had radiological joint erosive arthritis of the hands and feet. Three were positive for RF (60%) and four were positive for anti-CCP (80%). Conclusion: Our study is the first study that demonstrates an involvement of atlo-axial junction in early rheumatoid arthritis using MRI; patients with more aggressive disease and with higher inflammation had an higher risk to develop early synovitis of atlo-axial joint. Our data suggest to study upper cervical spine in patients with early rheumatoid arthritis with MRI, even without cervical pain but with an erosive and active disease. Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 68, supplement 3, year 2009, page 88Session: Abstract Session: Imaging (Oral Presentations )