title: Anatomo-metabolic characteristics of atelectasis in F-18 FDG-PET/CT imaging.
abstract: OBJECTIVE
  To evaluate the structural and metabolic characteristics of atelectasis in FDG-PET/CT.
  
  
  METHODS
  Twenty one consecutive patients (13 males, 8 females, median age 67 years) with CT features of atelectasis, undergoing PET/CT imaging for preoperative staging of histologically proven malignancies (20 lung cancer and 1 ovarian cancer metastasis to lung), were included in the study.
  
  
  RESULTS
  Hounsfield units of atelectasis (-383.58+/-189, range -631 to 82) were significantly higher than in normal lung (-756+/-67.46, range -839 to -555; P=0.0001), and lower than in malignant tissue (35+/-19, range 4-77; P=0.0001). The main patterns of FDG uptake observed in atelectasis were diffuse and homogenous. The standard uptake value (SUV) in atelectasis was low to moderate (SUV(avg): 1.13+/-0.50; SUV(max): 1.44+/-0.54), and generally lower than in tumor tissue (SUV(avg): 6.25+/-3.58, range 2.0-16.5), but always higher than in normal lung (0.56+/-0.18 and 0.70+/-0.23, respectively) (P=0.0001). There was a positive correlation between the density of atelectatic lesions and the degree of uptake, with no relationship to size.
  
  
  CONCLUSIONS
  There is a positive relationship between the density of collapsed lung and the intensity of FDG uptake. FDG uptake in atelectasis is higher than in normal lung, and generally lower than in tumor tissue.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St., Boston, MA 02115, USA. vgerbaudo@partners.org
authors.forename: Victor H
authors.initials: VH
authors.lastname: Gerbaudo
authors.forename: Barry
authors.initials: B
authors.lastname: Julius
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D001261:Pulmonary Atelectasis / Q000000981:diagnostic imaging* / Q000378:metabolism; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18