Localization of peripheral 18 F-fluoride accumulation in glucose-6-phosphate isomerase–induced arthritis. (A) In naive mice, administration of 18 F-fluoride resulted in low bone tracer accumulation in the subtalar joints. Under acute arthritic conditions (day 14 (d14)), there was distinct radiotracer signaling at sites of manifested disease, whereas increased 18 F-fluoride uptake was detectable in chronic arthritis (d28). In late remitting arthritis (d50), 18 F-fluoride uptake declined. Shown are representative images of murine hindpaws obtained with micro–computed tomography (μCT; top), 18 F-fluoride positron emission tomography (PET; middle) and coregistered PET and CT (bottom). (B) High-resolution μCT images of hindpaws obtained before arthritis onset (left) and with chronic arthritis (right) reveal the impact of inflammatory autoimmune disease on bone and joint integrity.