title: Spiral CT colonography: reader agreement and diagnostic performance with two- and three-dimensional image-display techniques.
abstract: OBJECTIVE
  To assess the diagnostic performance and reader agreement with two-dimensional (2D) and three-dimensional (3D) display techniques for detecting colorectal polyps with spiral computed tomographic (CT) colonography.
  
  
  METHODS
  A test set of 30 colonic segments was developed from spiral CT colonographic studies (12 with polyps and 18 without). The 12 segments with polyps contained 22 lesions (11 polyps <10 mm, 11 polyps or cancers >/=10 mm), with all findings verified with colonoscopy. Three specific 2D and 3D image-display techniques were tested. Three experienced abdominal radiologists independently analyzed each test case and were retested 6 weeks later.
  
  
  RESULTS
  The results of readings 1 and 2 were similar for all image-display techniques among the readers. Pooled segment results were sensitivity of 89%-92% and specificity of 72%-83%. Pooled polyp size results for sensitivity and positive predictive value were 77%-86% and 74%-86% (all polyps, n = 22), 91%-100% and 85%-100% (polyps or cancers >10 mm, n = 11), and 61%-73% and 61%-80% (polyps 5-9 mm, n = 11), respectively. Overall intraobserver agreement was good for the three display techniques (kappa, 0.60-1.00); however, interobserver agreement for 2D multiplanar reformation was lower (kappa, 0.53-0.80).
  
  
  CONCLUSIONS
  Among experienced abdominal radiologists, similar diagnostic performance in polyp detection was found among 2D multiplanar reformation and 3D display techniques, although individual cases showed improved characterization with 3D display techniques. Evaluation of reader agreement demonstrated good intraobserver agreement, with variable interobserver agreement.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 S Kingshighway Blvd, St Louis, MO 63110, USA. mcfarlandb@mir.wustl.edu
authors.forename: E G
authors.initials: EG
authors.lastname: McFarland
authors.forename: J A
authors.initials: JA
authors.lastname: Brink
authors.forename: T K
authors.initials: TK
authors.lastname: Pilgram
authors.forename: J P
authors.initials: JP
authors.lastname: Heiken
authors.forename: D M
authors.initials: DM
authors.lastname: Balfe
authors.forename: D A
authors.initials: DA
authors.lastname: Hirselj
authors.forename: L
authors.initials: L
authors.lastname: Weinstock
authors.forename: B
authors.initials: B
authors.lastname: Littenberg
mesh_terms: D003106:Colon / Q000000981:diagnostic imaging*; D003111:Colonic Polyps / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*