title: The value of delayed (18)F FDG-PET imaging in diagnosis of solitary pulmonary nodules: A preliminary study on 28 patients.
abstract: OBJECTIVE
  The aim of this study was to investigate whether adding delayed phase imaging can improve diagnostic ability of (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) in evaluating solitary pulmonary nodules (SPNs).
  
  
  METHODS
  28 patients with SPNs received dual-phase (18)F-FDG PET at 1h and 2h after (18)F-FDG injection during Feb 2009 to Jun 2011were included in this retrospective study. Their final diagnosis was confirmed by pathological examination in 27 cases and clinical follow-up in 1 case. The standardized uptake value (SUV) of early and delayed phases of all lesions was measured.
  
  
  RESULTS
  The 28 SPNs included 9 benign lesions and 19 malignant lesions. Using SUV ≥2.5 as a criteria for malignancy, the sensitivity, specificity, and accuracy were 52.6%, 55.6% and 53.6% respectively at early phase; 68.4%, 55.6% and 64.3% respectively at early and delayed phases combined. Combined early and delayed phase scans combined picked up 3 additional malignant lesions from the 14 lesions with an initial SUV value less than 2.5, and there was no additional false positive result with the benign lesions.
  
  
  CONCLUSIONS
  Adding delayed phase scanning resulted in correct diagnosis of three malignant lesions with an initial SUV value less than 2.5. Delayed phase scanning can be recommended in the SPNs with SUV less than 2.5 at early phase.
authors.affiliation: PET/CT Center, Shenzhen Health Committee Office, Shenzhen 518020, China;
authors.forename: Peng
authors.initials: P
authors.lastname: Yang
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Xu
authors.forename: Xiao-Jing
authors.initials: XJ
authors.lastname: Liu
authors.forename: Jing-Shan
authors.initials: JS
authors.lastname: Gong