title: PET-CT evaluation of solitary pulmonary nodules: correlation with maximum standardized uptake value and pathology.
abstract: OBJECTIVE
  18-fluorine fluorodeoxyglucose ((18)F-FDG) positron emission tomography-computed tomography (PET-CT) has an established role for the characterization of solitary pulmonary nodules (SPN). Visual assessment of nodule morphology, together with maximum standardized uptake value (SUVmax), is used to estimate likelihood of malignancy. We correlated SUVmax value with pathology of SPN and assessed diagnostic accuracy in differentiating malignant from benign nodule, using 2.5 as threshold SUVmax.
  
  
  METHODS
  Retrospective review of PET-CT scans for SPN characterization between April 2008 and June 2011 was performed. Only cases with pathological verification were included.
  
  
  RESULTS
  A total of 641 PET-CTs were performed for SPN characterization and staging; 186 patients (77 males, 109 females) with pathological confirmation were included, and 158 (85 %) nodules were malignant: adenocarcinomas (n = 66), squamous cell carcinomas (n = 40), and metastases (n = 20) were the commonest. 28 lesions (15 %) were benign, including granuloma/chronic inflammation (n = 8), infection (n = 7), and hamartomas (n = 5). Using cutoff SUVmax of 2.5, the accuracy of PET-CT in diagnosing malignant SPN is 81.2 %, with sensitivity 86.7 %, specificity 50 %, PPV 90.7 %, and NPV 40 %. The likelihood of malignancy increases with SUVmax. Nevertheless, even with SUVmax <2.5, there is a 62 % chance that a nodule is malignant.
  
  
  CONCLUSIONS
  Although PET-CT is useful in diagnostic workup of SPN, it cannot replace "gold standard" tissue diagnosis.
authors.affiliation: West of Scotland PET Centre, Beatson Oncology Centre, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, G12 0YN, UK.
authors.forename: Yee Ting
authors.initials: YT
authors.lastname: Sim
authors.forename: Yong Geng
authors.initials: YG
authors.lastname: Goh
authors.forename: Mary Frances
authors.initials: MF
authors.lastname: Dempsey
authors.forename: Sai
authors.initials: S
authors.lastname: Han
authors.forename: Fat Wui
authors.initials: FW
authors.lastname: Poon
mesh_terms: D003937:Diagnosis, Differential; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D064847:Multimodal Imaging / Q000379:methods*; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18