The role of 18F-fluorodeoxyglucose-positron emission tomography in the assessment of disease activity in patients with takayasu arteritis

Objective The assessment of disease activity in Takayasu arteritis (TA) is difficult in clinical situations because clinical symptoms and laboratory parameters do not always reflect the actual inflammation of the arterial wall. We undertook this study to comprehensively investigate the role of F-18-fluorodeoxyglucosepositron emission tomography (FDG-PET) in the assessment of disease activity in patients with TA. Methods. We performed a retrospective chart review of 53 FDG-PET scans in 38 patients with TA. We measured F-18-fluorodeoxyglucose (F-18-FDG) accumulation in the vascular wall of the large vessel using semiquantitative (visual grade) and quantitative (standard uptake value intensity) analyses. Clinical disease activity was evaluated based on the National Institutes of Health criteria for active TA, and erythrocyte sedimentation rates (ESRs) and C-reactive protein (CRP) levels were measured. Results. At baseline, active vascular F-18-FDG uptake (visual grade > 2) was observed in 18 of 24 patients with active disease and in 5 of 14 patients with inactive disease. There was a significant association between clinical disease activity and disease activity judged by FDG-PET (P = 0.008). Visual grade, standard uptake value intensity, and the number of vascular lesions with active F-18-FDG uptake were significantly higher in patients with active disease and correlated well with the ESR and CRP levels. In 15 followup FDG-PET scans, the changes in visual grade, areas of active vascular F-18-FDG uptake, and standard uptake value intensity reflected changes in clinical disease activity. Conclusion. F-18-FDG uptake was associated with clinical disease activity and markers of inflammation, and FDG-PET reflected changes in clinical disease activity in patients with TA. FDG-PET may be a useful tool for aiding in the assessment of disease activity in patients with TA.