title: Is (18)F-fluorodeoxyglucose positron emission tomography scanning a reliable way to assess disease activity in Takayasu arteritis?
abstract: OBJECTIVE
  (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scanning has been proposed as a new way of assessing disease activity in Takayasu arteritis (TA), but previous studies have used the nonvalidated National Institutes of Health (NIH) global activity criteria, and thus might be biased. This study was undertaken to determine the value of PET scanning for assessment of disease activity in TA, by comparing PET scan data with clinical, biologic, and magnetic resonance imaging (MRI) data assessed separately.
  
  
  METHODS
  Twenty-eight patients with TA (according to the American College of Rheumatology criteria) underwent a total of 40 PET scans. Images were reviewed by 2 pairs of independent nuclear medicine physicians and assessed for pattern and intensity of vascular uptake. TA activity data were obtained within 15 days of the PET scans.
  
  
  RESULTS
  PET scanning revealed abnormal vascular uptake in 47% of the 40 examinations. The uptake intensity grade was 0 in 7 scans, grade 1 in 7 scans, grade 2 in 13 scans, and grade 3 in 13 scans. Morphologic analysis was conducted by grading the pattern of the vascular uptake as diffuse (73%), segmental (20%), or focal (13%). There was a trend toward an association between clinically active disease and the semiquantitative assessment of FDG uptake (P = 0.08). We found no statistical association between levels of acute-phase reactants and intensity of uptake. There was no significant association between the semiquantitative assessment of FDG uptake and the presence of vascular wall thickening (P = 0.23), gadolinium uptake (P = 0.73), or the presence of vascular wall edema (P = 0.56).
  
  
  CONCLUSIONS
  Our findings indicate that there is no association between FDG vascular uptake intensity and clinical, biologic, or MRI assessment of disease activity. Previous studies using the nonvalidated NIH global activity criteria are likely biased.
authors.affiliation: Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, and Université Paris 6, Paris, France.
authors.forename: Laurent
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authors.lastname: Arnaud
authors.forename: Julien
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authors.lastname: Haroche
authors.forename: Zoulikha
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authors.lastname: Malek
authors.forename: Frédérique
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authors.lastname: Archambaud
authors.forename: Laetitia
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authors.lastname: Gambotti
authors.forename: Gilles
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authors.lastname: Grimon
authors.forename: Aurélie
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authors.lastname: Kas
authors.forename: Nathalie
authors.initials: N
authors.lastname: Costedoat-Chalumeau
authors.forename: Patrice
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authors.lastname: Cacoub
authors.forename: Dan
authors.initials: D
authors.lastname: Toledano
authors.forename: Philippe
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authors.lastname: Cluzel
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Piette
authors.forename: Zahir
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authors.lastname: Amoura