title: PET scanning of macrophages in patients with scleroderma fibrosing alveolitis.
abstract: BACKGROUND
  Assessment of disease activity in fibrosing alveolitis due to systemic sclerosis (FASSc) is difficult without using invasive investigation. A repeatable noninvasive method of assessing disease at a cellular level such as with positron emission tomography (PET) could be of great value in evaluating high-resolution changes in the pathological process.
  
  
  OBJECTIVE
  To investigate whether the level of inflammatory cell traffic and lung density in FASSc, imaged in vivo by PET, is different to controls and whether they are associated with changes in pulmonary function indices.
  
  
  METHODS
  We used PET to measure lung density and tissue uptake of (11)C-[R]-PK11195, a ligand that binds to receptors found in abundance in macrophages. Fifteen patients with FASSc were compared to seven controls.
  
  
  RESULTS
  A trend of reduced uptake of (11)C-[R]-PK11195 was observed in FASSc patients (P=.09) and correlated inversely with lung density (r=-.62; P<.05), which was significantly elevated in FASSc [0.35+/-0.02 vs. 0.23+/-0.02 g/cc (mean+/-S.E.M.); P<.005].
  
  
  CONCLUSIONS
  These results demonstrate that inflammatory cell traffic and lung density can be imaged in vivo in FASSc using PET, and that this approach might be of potential value in understanding, in situ, components of pathogenesis that may have value for prognosis.
authors.affiliation: Imperial College London, Hammersmith Campus, London, UK. Howard.Branley@whittington.nhs.uk
authors.forename: Howard M
authors.initials: HM
authors.lastname: Branley
authors.forename: Roland M
authors.initials: RM
authors.lastname: du Bois
authors.forename: Athol U
authors.initials: AU
authors.lastname: Wells
authors.forename: Hazel A
authors.initials: HA
authors.lastname: Jones
mesh_terms: D002250:Carbon Radioisotopes; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007546:Isoquinolines / Q000378:metabolism*; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008264:Macrophages / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011658:Pulmonary Fibrosis / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology; D019275:Radiopharmaceuticals / Q000378:metabolism*; D012595:Scleroderma, Systemic / Q000150:complications*
chemical_list: D002250:Carbon Radioisotopes; D007166:Immunosuppressive Agents; D007546:Isoquinolines; D019275:Radiopharmaceuticals; C037850:PK 11195