Background: Magnetic resonance imaging (MRI), which has recently become the leading imaging modality in the study of ankylosing spondylitis (AS), has not been evaluated in the assessment of disease-specific changes at the craniocervical junction (CCJ) in patients with AS.

Objectives: To describe the spectrum of active inflammatory lesions at the CCJ using MRI in a cohort of patients with AS and neck pain.

Methods: The study included 18 patients with AS presenting with neck pain and a control group of 9 fibromyalgia patients matched for age and levels of neck pain. All patients underwent a focused rheumatologic examination, X-ray of the cervical spine, and a 3T MRI study, which included STIR, CUBE T2, FSE and FSE FAT SAT sequences before and after administration of gadolinium.

Results: The median age of AS patients was 43 years with a median disease duration of 7 years. Fifteen of 18 patients were under biologic treatment. Seven of 18 AS patients had evidence of cervical syndesmophytes on X-ray films. Active inflammatory lesions of atlanto-occipital joints and apical and alar ligaments were detected in MRIs in 2 out of the 18 patients with AS and in none of the patients with fibromyalgia. Both AS patients with active inflammation of CCJ detected on MRI received treatment with biological agents prior to and during the study.

Conclusions: Active inflammation of both entheses and joints of the CCJ can be demonstrated by MRI in patients with AS.