THU0622 MRI OF THE CRANIO-CERVICAL JUNCTION IN RHEUMATOID ARTHRITIS – DEFINITION OF NORMAL AND PATHOLOGICAL FINDINGS

Abstract

Background In rheumatoid arthritis (RA), disease involvement at the cervical spine is common and may lead to malposition of the dens axis, resulting in severe neurological impairment. To date, malalignment is mostly described by X-rays. Objectives The aim of this investigation was to systematically define osseous and ligamentous MRI-findings in cranio-cervical RA in comparison to a control group without the disease. Methods MRI datasets of patients with cranio-cervical RA were identified retrospectively from the institutional image database and matched regarding age and gender with control patients. All image datasets were systematically reviewed for: position and morphology of dens axis (including erosions and osteitis); width and angle of the cranio-cervical joints; length, angle and visibility of peridental ligaments; vascularization of peridental soft tissue. Prior to image analysis, an atlas of normal findings and measurements was comprised. Group differences were investigated using students T-test for continuous data and Fisher’s exact test for nominal and ordinal data. Results A total of 40 patients were included in this retrospective case-control study, 20 in each group (RA and control). Position of dens was significantly more cranial in the RA group (dens to McGregor line: -1.62 mm for RA vs. 2.15 mm for controls, p=0.002; dens to McRae line: 3.20 for RA vs. 5.36 for controls, p Conclusion With this case control study, MRI data on the position of the osseous and ligamentous structures of the cranio-cervical junction in patients with rheumatoid arthritis are available for the first time. Cranialization of the dens axis and signal changes of the transverse ligament and the alar ligaments are the most obvious findings. In a next step, the diagnostic value of MRI of the cervical spine in RA should be prospectively investigated and the available scoring system developed into an internationally established outcome measure. Disclosure of Interests [2] Katharina Ziegeler: None declared, Christoph Korsing: None declared, Mattias Bollow: None declared, Kay Geert A. Hermann Speakers bureau: AbbVie, MSD, Pfizer, UCB, Samsung