title: Detection of inflammatory lesions by f-18 fluorodeoxyglucose positron emission tomography in patients with polymyositis and dermatomyositis.
abstract: OBJECTIVE
  To evaluate the usefulness of F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) imaging in the management of patients with inflammatory myopathy. We examined whether FDG-PET scanning detects myositis or extramuscular lesions in patients with polymyositis (PM) and dermatomyositis (DM).
  
  
  METHODS
  FDG-PET imaging was performed in 24 patients with active inflammatory myopathy (PM, 11; DM, 13). The images were read by radiologists in a blinded manner. FDG uptake into muscles was judged positive when the intensity of muscles was higher than or equal to that of the liver. As controls, FDG imaging findings of patients with a lung mass and without muscle diseases were used. To investigate associations between FDG-PET findings and clinical/laboratory findings, the patients' medical records were reviewed retrospectively.
  
  
  RESULTS
  Increased FDG uptake in muscles was found in 8 of 24 (33%) patients. In 67 of 69 (97%) controls without muscle diseases, no muscle FDG uptake was detected. The sensitivity of FDG-PET to detect myositis was lower than that of electromyogram (EMG), magnetic resonance imaging, and muscle biopsy. There were no significant differences in clinical manifestations between patients with and without increased FDG uptake in muscles, although patients with FDG muscle uptake had a tendency to have extended myositis with endomysial cell infiltration. FDG-PET detected neoplasms in patients with associated malignancy. FDG uptake in lungs was found in 7 of 18 patients with interstitial lung disease.
  
  
  CONCLUSIONS
  FDG-PET imaging has limited usefulness for the evaluation of myositis in patients with PM/DM because of its low sensitivity, although it might be useful for detection of malignancy in these patients.
authors: 880 Kita-Kobayashi, Mibu, Tochigi 321-0293, Japan. kurasawa@dokkyomed.ac.jp.
authors: Takayoshi
authors: T
authors: Owada
authors: Reika
authors: R
authors: Maezawa
authors: Kazuhiro
authors: K
authors: Kurasawa
authors: Harutsugu
authors: H
authors: Okada
authors: Satoko
authors: S
authors: Arai
authors: Takeshi
authors: T
authors: Fukuda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003882:Dermatomyositis / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D017285:Polymyositis / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D012189:Retrospective Studies
chemical_list: D019788:Fluorodeoxyglucose F18