title: Assessment of indeterminate pulmonary nodules detected in lung cancer screening: Diagnostic accuracy of FDG PET/CT.
abstract: A major drawback of lung cancer screening programs is the high frequency of false-positive findings on computed tomography (CT). We investigated the accuracy of selective 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (FDG) Positron Emission Tomography/Computed Tomography (PET/CT) scan in assessing radiologically indeterminate lung nodules detected in lung cancer screening.
  
  
  
  FDG PET/CT was performed to characterize 64 baseline lung nodules >10mm and 36 incidence nodules detected on low-dose CT screening in asymptomatic current or former smokers (83 men, age range 40-83 years) at high risk for lung cancer. CT images were acquired without intravenous contrast. Nodules were analyzed by size, density, and metabolic activity and visual scored on a 5-point scale for FDG uptake. Nodules were classified as negative for malignancy when no FDG uptake was observed, or positive when focal uptake was observed in the visual analysis, and the maximum standardized uptake value (SUVmax) was measured. Final diagnosis was based on histopathological evaluation or at least 24 months of follow-up.
  
  
  
  A total of 100 nodules were included. The prevalence of lung cancer was 1%. The sensitivity, specificity, NPV and PPV of visual analysis to detect malignancy were 84%, 95%, 91%, and 91%, respectively, with an accuracy of 91% (AUC 0.893). FDG PET/CT accurately detected 31 malignant tumors (diameters 9-42mm, SUVmax range 0.6-14.2) and was falsely negative in 6 patients. With SUVmax thresholds for malignancy of 1.5, 2, and 2.5, specificity was 97% but sensitivity decreased to 65%, 49%, and 46% respectively, and accuracy decreased to 85%, 79%, and 78% respectively (AUC 0.872).
  
  
  
  The visual analysis of FDG PET/CT scan is highly accurate in characterizing indeterminate pulmonary nodules detected in lung cancer screening with low-dose CT. Semi-quantitative analysis does not improve the accuracy of FDG PET/CT over that obtained with a qualitative method for lung nodule characterization.
authors.affiliation: Department of Nuclear Medicine, Clinica Universidad de Navarra, Pamplona, Spain. Electronic address: mjgarciave@unav.es.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Garcia-Velloso
authors.affiliation: Department of Radiology, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Gorka
authors.initials: G
authors.lastname: Bastarrika
authors.affiliation: Department of Pulmonology, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Juan P
authors.initials: JP
authors.lastname: de-Torres
authors.affiliation: Department of Pathology, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Maria D
authors.initials: MD
authors.lastname: Lozano
authors.affiliation: Department of Pulmonology, Complejo Hospitalario de Navarra, Pamplona, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Sanchez-Salcedo
authors.affiliation: Department of Nuclear Medicine, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Lidia
authors.initials: L
authors.lastname: Sancho
authors.affiliation: Division of Biostatistics, Research Support Service, Central Clinical Trials Unit, Clinica Universidad de Navarra, Department of Preventive Medicine and Public Health, Medical School, University of Navarra, Pamplona, Spain.
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Nuñez-Cordoba
authors.affiliation: Department of Pulmonology, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Arantza
authors.initials: A
authors.lastname: Campo
authors.affiliation: Department of Pulmonology, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Alcaide
authors.affiliation: Department of Thoracic Surgery, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Wenceslao
authors.initials: W
authors.lastname: Torre
authors.affiliation: Department of Nuclear Medicine, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Richter
authors.affiliation: Department of Pulmonology, Clinica Universidad de Navarra, Pamplona, Spain.
authors.forename: Javier J
authors.initials: JJ
authors.lastname: Zulueta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging* / Q000473:pathology; D015588:Observer Variation; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: (18)F-FDG; Diagnostic accuracy; Lung cancer screening; Lung nodule; PET/CT