title: A problem in diagnosing N3 disease using FDG-PET in patients with lung cancer--high false positive rate with visual assessment.
abstract: OBJECTIVE
  To evaluate the accuracy of diagnosing N3 disease using positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in patients with pulmonary disease.
  
  
  METHODS
  Twenty patients diagnosed as FDG-PET N3 were enrolled. On FDG-PET, lymph nodes were considered to be positive when increased uptake as compared with that of the surrounding mediastinum was visually observed, or the mean standardized uptake ratio (SUR) was more than 2, 2.5, or 3. On CT, lymph nodes exceeding 1 cm in the shortest diameter were regarded as positive.
  
  
  RESULTS
  The PET result was true positive (TP) in 2 patients and false positive (FP) in 18 with an overall accuracy (OA) of 10% using visual criteria. Using an SUR of more than 2.5, the result was TP in 2, FP in 3, and true negative (TN) in 15, the false negative (FN) in 0, with an OA of 85%. CT diagnosis was TP in 2, FP in 9, and TN in 9 with an OA of 55%. The accuracy using the SUR criteria of more than 2.5 was superior to that of CT.
  
  
  CONCLUSIONS
  Of 20 patients with the diagnosis of PET N3, we found frequent over-diagnosis in nodal staging using the visual criteria.
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Hara
authors.forename: Norio
authors.initials: N
authors.lastname: Shiraki
authors.forename: Masato
authors.initials: M
authors.lastname: Itoh
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
authors.forename: Akihiko
authors.initials: A
authors.lastname: Iida
authors.forename: Masami
authors.initials: M
authors.lastname: Nishio
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D003951:Diagnostic Errors; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D015588:Observer Variation; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18