title: Operator-dependent reproducibility of size measurements of small phantoms and lung nodules examined with low-dose thin-section computed tomography.
abstract: OBJECTIVE
  We sought to assess the reproducibility of size measurements of small lung nodules examined with low-dose thin-section computed tomography (LDTSCT).
  
  
  METHODS
  Three radiologists measured volume with a semiautomatic tool and diameters manually of 20 (equivalent diameter range, 5.3-11 mm) phantom nodules and 37 (mean diameter range, 5-8.5 mm) lung nodules in subjects undergoing LDTSCT.
  
  
  RESULTS
  In phantoms, the worst 95% limits of agreement (95% LA) for volume were -3.0% and 3.0% within operator and -3.1% and 2.8% between operators. The coefficient of repeatability (CR) for diameter ranged between 0.51 and 0.67 mm within operator and the 95% LA were from -0.71 to 0.71 mm between operators. In nodules, the worst intraoperator 95% LA for volume were -14.4% and 17.6% within operator and -13.1% and 14.2% between operators. The CR for diameter ranged between 0.48 and 0.73 mm within operator and the 95% LA were from -1.16 to 1.16 mm between operators.
  
  
  CONCLUSIONS
  Operator-dependent variability of size measurements of small nodules examined with LDTSCT is not negligible and should be considered in lung cancer-screening studies.
authors.affiliation: Radiodiagnostic, Department of Clinical Physiopathology, University of Florence, Florence, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Picozzi
authors.forename: Stefano
authors.initials: S
authors.lastname: Diciotti
authors.forename: Massimo
authors.initials: M
authors.lastname: Falchini
authors.forename: Silvia
authors.initials: S
authors.lastname: Foresti
authors.forename: Francesca
authors.initials: F
authors.lastname: Gallesi
authors.forename: Edoardo
authors.initials: E
authors.lastname: Cavigli
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Livi
authors.forename: Natale
authors.initials: N
authors.lastname: Villari
authors.forename: Mario
authors.initials: M
authors.lastname: Mascalchi
mesh_terms: D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D015588:Observer Variation; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging / Q000453:epidemiology; D014057:Tomography, X-Ray Computed / Q000379:methods*