title: Diagnostic performance of virtual gastroscopy using MDCT in early gastric cancer compared with 2D axial CT: focusing on interobserver variation.
abstract: OBJECTIVE
  The objective of our study was to assess the diagnostic performance of virtual gastroscopy using MDCT for the detection of early gastric cancer (EGC) compared with 2D axial CT, focusing on interobserver reliability.
  
  
  METHODS
  During an 11-month period, we performed CT examinations of 94 consecutive patients with EGC and a control group composed of 68 patients without EGC. Three radiologists retrospectively interpreted the 2D axial CT and virtual gastroscopy images. Diagnostic performances were compared within each observer using the area under the receiver operating characteristic curve (A(z)). Sensitivity and specificity were also calculated for each individual observer. The simple kappa statistic was used to evaluate interobserver reliability in the detection of EGC.
  
  
  RESULTS
  The diagnostic performance for overall lesion detection in patients with EGC was significantly higher with virtual gastroscopy (A(z) = 0.829-0.885) than with 2D axial CT (A(z) = 0.734-0.793) (p < 0.001). The sensitivity and specificity of virtual gastroscopy for EGC were 78.7-84.0% and 83.8-91.2%, respectively. The sensitivity and specificity of 2D axial CT for EGC were 62.8-69.2% and 83.8-92.7%, respectively. Virtual gastroscopy showed a higher sensitivity for EGC than 2D axial CT (p < 0.001). The interobserver reliabilities showed moderate to substantial agreement (kappa = 0.40-0.74 for 2D axial CT, kappa = 0.57-0.71 for virtual gastroscopy).
  
  
  CONCLUSIONS
  Virtual gastroscopy showed excellent results with a good interobserver reliability for the detection of EGC compared with 2D axial CT.
authors.affiliation: Department of Radiology, Soonchunhyang University Hospital, 657 Hannam-Dong, Youngsan-Ku, Seoul 140-743, Korea. junghkim@hosp.sch.ac.kr
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Hyo Won
authors.initials: HW
authors.lastname: Eun
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Choi
authors.forename: Seong Sook
authors.initials: SS
authors.lastname: Hong
authors.forename: Weechang
authors.initials: W
authors.lastname: Kang
authors.forename: Yong Ho
authors.initials: YH
authors.lastname: Auh
mesh_terms: D016022:Case-Control Studies; D005260:Female; D005773:Gastroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014584:User-Computer Interface