Assessment of typical SpA lesions on MRI of the spine: do local readers and central readers agree in the DESIR-cohort at baseline?

Comparing local reading (LocR) with central reading (CentR) of typical spondyloarhritis lesions including bone marrow edema (BME) and structural lesions on magnetic resonance imaging of the spine (MRI-spine), in patients with inflammatory back pain (IBP; ≥3 months, <3 years). Baseline data of 667 patients, age 18-50 years, from the Devenir des Spondylarthopathies Indifferenciees Recentes (DESIR)-cohort were used. Two trained central readers scored anterior and posterior corner BME, fatty lesions, erosions and syndesmophytes on MRI-spine. Presences of lesions, based on average scores, were used for CentR. A local radiologist and/or rheumatologist scored MRI-spine on presence/doubt/absence of 'inflammation' and 'structural lesions'. Agreement between central readers and readings was calculated (Cohen's kappa: κ). Agreement between central readers was moderate (BME κ = 0.55, fatty lesions κ = 0.50) to slight (erosions κ = 0.12, syndesmophytes κ = 0.19). Agreement between LocR and CentR was κ = 0.32 (BME) and κ = 0.13 (structural lesions). In 78/160 patients (48.8%) LocR were in doubt while CentR scored BME lesions, for structural lesions this was 17.8% (28/157 patients). Agreement between 2 central readers for scoring spondyloarhritis-like lesions on MRI-spine was moderate but better compared to LocR and CentR agreement. LocR often doubt about the presence of MRI-spine lesions while central trained readers score lesions.