TY - JOUR T1 - Detection of Subclinical Synovitis with Macrophage Targeting and Positron Emission Tomography in Patients with Rheumatoid Arthritis without Clinical Arthritis JF - The Journal of Rheumatology JO - J Rheumatol DO - 10.3899/jrheum.140059 SP - jrheum.140059 AU - Yoony Y.J. Gent AU - Nazanin Ahmadi AU - Alexandre E. Voskuyl AU - Nikie Hoetjes AU - Cornelis van Kuijk AU - Karin Britsemmer AU - Franktien Turkstra AU - Maarten Boers AU - Otto S. Hoekstra AU - Conny J. van der Laken Y1 - 2014/10/01 UR - http://www.jrheum.org/content/early/2014/09/25/jrheum.140059.abstract N2 - Objective To determine whether macrophage targeting by (R)-11C-PK11195 positron emission tomography (PET) can visualize subclinical joint inflammation in patients with rheumatoid arthritis (RA) without clinical arthritis during or after treatment, with flare as clinical outcome measure. Methods (R)-11C-PK11195 PET and contrast-enhanced magnetic resonance imaging (MRI) of hands/wrists were performed in 29 patients with RA without clinical arthritis. (R)-11C-PK11195 PET uptake (semiquantitative score 0–3) in metacarpophalangeal, proximal interphalangeal, and wrist joints (i.e., 22 joints per patient) was scored and summed to obtain a cumulative PET score (range 0–66). Rheumatoid Arthritis Magnetic Resonance Imaging Scoring (RAMRIS) was performed on similar joints. Synovitis and bone marrow edema scores (> 1) were summed to obtain a cumulative MRI score (range 0–288). Occurrence of flare was determined during 3-year followup. Results Flare was observed in 17/29 patients (59%). (R)-11C-PK11195 PET showed enhanced tracer uptake in 16/29 patients (55%), of which 11 (69%) developed a flare. Highest cumulative PET scores (> 6, n = 3) corresponded with highest cumulative MRI scores (> 39) and were related to development of flare in hands/wrists within 6 months. Cumulative PET scores of patients developing a flare were higher than those of patients without a flare [median (interquartile range) 2 (0–4.5) vs 0 (0–1), p < 0.05]. In contrast, no significant differences were found between cumulative MRI scores of patients with and without a flare. Conclusion (R)-11C-PK11195 PET showed enhanced uptake, pointing to presence of subclinical synovitis in over half of patients without clinical arthritis. (R)-11C-PK11195 PET may be of value for prediction of exacerbation of RA, since cumulative PET scores > 1 were associated with development of flare within 3 years. ER -