title: A comparison of the diagnostic accuracy of 18F-FDG PET and CT in the characterization of solitary pulmonary nodules.
abstract: CT and PET are widely used to characterize solitary pulmonary nodules (SPNs). However, most CT accuracy studies have been performed with outdated technology and methods, and previous PET studies have been limited by small sample sizes and incomplete masking. Our objective was to compare CT and PET accuracy in veterans with SPN.
  
  
  METHODS
  Between January 1999 and June 2001, we recruited 532 participants with SPNs newly diagnosed on radiography and untreated. The SPNs were 7-30 mm. All patients underwent (18)F-FDG PET and CT. A masked panel of 3 PET and 3 CT experts rated the studies on a 5-point scale. SPN tissue diagnosis or 2-y follow-up established the final diagnosis.
  
  
  RESULTS
  A definitive diagnosis was established for 344 participants. The prevalence of malignancy was 53%. The average size was 16 mm. Likelihood ratios (LRs) for PET and CT results for combined ratings of either definitely benign (33% and 9% of patients, respectively) or probably benign (27% and 12%) were 0.10 and 0.11, respectively. LRs for PET and CT results for combined ratings of indeterminate (1% and 25%), probably malignant (21% and 39%), or definitely malignant (35% and 15%) were 5.18 and 1.61, respectively. Area under the receiver operating characteristic curve was 0.93 (95% confidence interval, 0.90-0.95) for PET and 0.82 (95% confidence interval, 0.77-0.86) for CT (P < 0.0001 for the difference). PET inter- and intraobserver reliability was superior to CT.
  
  
  CONCLUSIONS
  Definitely and probably benign results on PET and CT strongly predict benign SPN. However, such results were 3 times more common with PET. Definitely malignant results on PET were much more predictive of malignancy than were these results on CT. A malignant final diagnosis was approximately 10 times more likely than a benign final diagnosis in participants with PET results rated definitely malignant.
authors.affiliation: Department of Radiology, Indiana University School of Medicine, University Hospital, Indianapolis, Indiana 46202-5253, USA. jwfletch@iupui.edu
authors.forename: James W
authors.initials: JW
authors.lastname: Fletcher
authors.forename: Steven M
authors.initials: SM
authors.lastname: Kymes
authors.forename: Michael
authors.initials: M
authors.lastname: Gould
authors.forename: Naomi
authors.initials: N
authors.lastname: Alazraki
authors.forename: R Edward
authors.initials: RE
authors.lastname: Coleman
authors.forename: Val J
authors.initials: VJ
authors.lastname: Lowe
authors.forename: Charles
authors.initials: C
authors.lastname: Marn
authors.forename: George
authors.initials: G
authors.lastname: Segall
authors.forename: Lyn A
authors.initials: LA
authors.lastname: Thet
authors.forename: Kelvin
authors.initials: K
authors.lastname: Lee
mesh_terms: D000465:Algorithms; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18