title: Uncertainty analysis of quantitative imaging features extracted from contrast-enhanced CT in lung tumors.
abstract: OBJECTIVE
  To assess the uncertainty of quantitative imaging features extracted from contrast-enhanced computed tomography (CT) scans of lung cancer patients in terms of the dependency on the time after contrast injection and the feature reproducibility between scans.
  
  
  METHODS
  Eight patients underwent contrast-enhanced CT scans of lung tumors on two sessions 2-7 days apart. Each session included 6 CT scans of the same anatomy taken every 15s, starting 50s after contrast injection. Image features based on intensity histogram, co-occurrence matrix, neighborhood gray-tone difference matrix, run-length matrix, and geometric shape were extracted from the tumor for each scan. Spearman's correlation was used to examine the dependency of features on the time after contrast injection, with values over 0.50 considered time-dependent. Concordance correlation coefficients were calculated to examine the reproducibility of each feature between times of scans after contrast injection and between scanning sessions, with values greater than 0.90 considered reproducible.
  
  
  RESULTS
  The features were found to have little dependency on the time between the contrast injection and the CT scan. Most features were reproducible between times of scans after contrast injection and between scanning sessions. Some features were more reproducible when they were extracted from a CT scan performed at a longer time after contrast injection.
  
  
  CONCLUSIONS
  The quantitative imaging features tested here are mostly reproducible and show little dependency on the time after contrast injection.
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA. Electronic address: jyang4@mdanderson.org.
authors.forename: Jinzhong
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: Lifei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: Xenia J
authors.initials: XJ
authors.lastname: Fave
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: David V
authors.initials: DV
authors.lastname: Fried
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: Francesco C
authors.initials: FC
authors.lastname: Stingo
authors.affiliation: Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: Chaan S
authors.initials: CS
authors.lastname: Ng
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: Laurence E
authors.initials: LE
authors.lastname: Court
mesh_terms: D016477:Artifacts; D000072226:Computed Tomography Angiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
chemical_list: D003287:Contrast Media