Rheumatoid arthritis of the craniocervical region: assessment and characterization of inflammatory soft tissue proliferations with unenhanced and contrast-enhanced CT

The aim of this study was to depict and characterize inflammatory soft tiss ue proliferations caused by rheumatoid arthritis (RA) in the craniocervical region by unenhanced and contrast-enhanced CT. Computed tomography of the craniocervical region was performed in 35 patients in the axial plane befor e and after the i.v. administration of contrast material. According to the densities and contrast enhancement of the inflammatory soft tissue prolifer ations, four groups were classified. Ancillary findings, such as a compress ion of the dural sac or spinal cord, erosions of the bony structures, and a tlantoaxial subluxation, were also evaluated. Inflammatory soft tissue prol iferations were depicted in 28 of 35 patients and could be differentiated b y unenhanced and contrast-enhanced CT according to the above defined criter ia: effusion in 6 patients (17%); hypervascular pannus in 8 (23 %); hypovas cular pannus in 5 (14 %); and fibrous tissue in 9 patients (26 %). A compre ssion of the dural sac was seen in 11 (31 %) patients; 3 of these had neuro logical symptoms. Erosions of the odontoid process were found in 20 (57 %) patients; 16 (80 %) of these also showed erosions of the atlas. Atlantoaxia l subluxation was seen in 11 (31%) patients. Inflammatory soft tissue proli ferations in the craniocervical region caused by RA can be reliably,demonst rated and classified by unenhanced and contrast-enhanced CT, which can diff erentiate between joint effusion and various forms of pannus and depict anc illary findings. Computed tomography is an alternative method for patients unable to undergo an MRI examination.