(18)F-FDG PET imaging of rheumatoid knee synovitis correlates with dynamic magnetic resonance and sonographic assessments as well as with the serum level of metalloproteinase-3.

Purpose: The aim of this study was to assess rheumatoid arthritis (RA) synovitis with positron emission tomography (PET) and( 18)F-fluorodeoxyglucose ((18)F-FDG) in comparison with dynamic magnetic resonance imaging (MRI) and ultrasonography (US).

Methods: Sixteen knees in 16 patients with active RA were assessed with PET, MRI and US at baseline and 4 weeks after initiation of anti-TNF-alpha treatment. All studies were performed within 4 days.