title: Patients with Takayasu's arteritis having persistent acute-phase response usually have an increased major vessel uptake by 18F-FDG-PET/CT.
abstract: OBJECTIVE
  Although not uniformly accepted, an increased uptake by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in large vessels is accepted to be a sign of active disease in Takayasu's arteritis (TAK). We aimed to investigate the value of 18F-FDG-PET/CT for clinical assessment in a subset of TAK patients having a persistent acute-phase response (APR) without any signs or symptoms of clinical disease activity.
  
  
  METHODS
  We studied 14 patients (mean age: 38.6 ± 13.9 years, Female/Male: 11/3, and disease duration: 5.7 ± 5 years). Patients were clinically inactive (according to the definition of activity by Kerr et al.), while categorized as having "persistent" disease activity by physician's global assessment due only to APR. 18F-FDG uptake was graded using a four-point scale from grade 0 (no uptake present) to grade 3 (high grade: uptake higher than that of liver). Any uptake in major vessels with a grade ≥ 2 was accepted to be "active."
  
  
  RESULTS
  Mean erythrocyte sedimentation rate was 50.8 ± 13.2 mm/hour and mean C-reactive protein level was 28.5 ± 22.1 mg/L. Active vasculitic lesions were observed by 18F-FDG-PET/CT in 9 of 14 (64.3%) patients. The median number of active vascular lesions was 2 (range: 1-5). A step-up treatment change was decided in 8 patients according to 18F-FDG-PET/CT results.
  
  
  CONCLUSIONS
  We observed increased 18F-FDG uptake in the majority of TAK patients with an increased APR, but clinically silent disease. 18F-FDG-PET/CT showed the presence and localization of active inflammation in the aorta and its branches. Although specificity for observed lesions is not clear, 18F-FDG-PET/CT imaging may influence physician's assessment of clinical activity and treatment choices in TAK.
authors: a Department of Rheumatology , Marmara University, School of Medicine , Pendik, Istanbul , Turkey.
authors: Fatma
authors: F
authors: Alibaz-Oner
authors: Fuat
authors: F
authors: Dede
authors: Tunc
authors: T
authors: Ones
authors: H Turgut
authors: HT
authors: Turoglu
authors: Haner
authors: H
authors: Direskeneli
mesh_terms: D000210:Acute-Phase Reaction; D000328:Adult; D001799:Blood Sedimentation; D001808:Blood Vessels / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D013625:Takayasu Arteritis / Q000175:diagnosis* / Q000378:metabolism; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002097:C-Reactive Protein
keywords: Activity; Acute-phase response; PET; Takayasu's arteritis