TY - JOUR T1 - Hybrid 18F-labeled Fluoride Positron Emission Tomography/Magnetic Resonance (MR) Imaging of the Sacroiliac Joints and the Spine in Patients with Axial Spondyloarthritis: A Pilot Study Exploring the Link of MR Bone Pathologies and Increased Osteoblastic Activity JF - The Journal of Rheumatology JO - J Rheumatol DO - 10.3899/jrheum.150250 SP - jrheum.150250 AU - Christian Buchbender AU - Benedikt Ostendorf AU - Verena Ruhlmann AU - Philipp Heusch AU - Falk Miese AU - Karsten Beiderwellen AU - Matthias Schneider AU - Juergen Braun AU - Gerald Antoch AU - Xenofon Baraliakos Y1 - 2015/07/01 UR - http://www.jrheum.org/content/early/2015/06/26/jrheum.150250.abstract N2 - Objective The biologically active molecule used in positron emission tomography (PET) for depiction of osteoblastic activity is 18F-labeled fluoride (18F-F). We examined whether inflammatory or chronic changes on magnetic resonance imaging (MRI) in the sacroiliac joints (SIJ) and the spines of patients with active ankylosing spondylitis (AS) are linked to osteoblastic activity, assessed by PET/MRI. Methods Thirteen patients with AS (mean age 37.8 ± 11.4 yrs, Bath AS Disease Activity Index > 4, no anti-TNF treatment) underwent 3-Tesla whole-spine and SIJ PET/MRI. Two independent readers recorded pathologic changes related to vertebral (VQ) or SIJ quadrants (SQ). Final scores were based on reader agreement. Results A total of 104 SQ and 1196 VQ were examined. In SIJ, bone marrow edema (BME) was seen in 44.2%, fat deposition (FD) in 42.3%, and 18F-F in 46.2% SQ. BME alone was associated with 18F-F in 78.6% and FD alone in only 7.7% SQ, while the combination BME/FD was associated with 18F-F in 72.2% SQ. Erosions, sclerosis, and ankylosis alone were rarely associated with 18F-F. In the spine, BME alone was seen in 9.9%, FD in 18.2%, and 18F-F in 5.4% VQ. BME alone was associated with 18F-F in 14.3% and FD alone in 8.7% VQ, while the combination BME/FD was associated with 18F-F in 40.6% VQ. Conclusion In this study of hybrid 18F-F PET/MRI of patients with active AS, we show that BME rather than chronic changes is associated with osteoblastic activity, while the combination of BME and FD showed the highest 18F-F uptake. The use of PET/MRI in prediction of future syndesmophyte formation in AS needs further exploration in prospective studies. ER -