title: Intraobserver and interobserver agreement of volume perfusion CT (VPCT) measurements in patients with lung lesions.
abstract: OBJECTIVE
  To evaluate intraobserver and interobserver agreement of manually encompassed lung lesions for perfusion measurements using volume-perfusion computed tomography (VPCT).
  
  
  METHODS
  Institutional review board approval and informed consent were obtained. HIPAA guidelines were followed. A 65-s dynamic study was acquired with scan parameters 80 kV, 60 mAs (80 mAs for patients ≥ 70 kg), 128 × 0.6mm collimation. Blood flow (BF), blood volume (BV) and K(trans) parameters were determined by syngo volume perfusion CT body with 88 lesions analyzed retrospectively.
  
  
  RESULTS
  Within-subject coefficients of variation for intraobserver agreement (range 6.59-12.82%) were superior to those for interobserver agreement (range 21.75-38.30%). Size-dependent analysis revealed lower agreements for lesions <4 cm as compared to larger lesions. Additionally, agreements of the upper, middle and lower lung zones were different.
  
  
  CONCLUSIONS
  Intraobserver agreement was substantial for VPCT lung cancer perfusion measurements encouraging the use for tumor characterization and therapy response monitoring. Interobserver agreement is limited and unexperienced readers should be trained before using this new method.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany. alexander.sauter@klinikum.uni-tuebingen.de
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Sauter
authors.forename: Anne
authors.initials: A
authors.lastname: Merkle
authors.forename: Maximilian
authors.initials: M
authors.lastname: Schulze
authors.forename: Daniel
authors.initials: D
authors.lastname: Spira
authors.forename: Juergen
authors.initials: J
authors.lastname: Hetzel
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Marius S
authors.initials: MS
authors.lastname: Horger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D055420:Perfusion Imaging / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*