title: Two-dimensional multiplanar and three-dimensional volume-rendered vascular CT in pancreatic carcinoma: interobserver agreement and comparison with standard helical techniques.
abstract: OBJECTIVE
  The purpose of this study was to compare two-dimensional curved multiplanar and three-dimensional reconstructions, routine axial presentations, and combined techniques in the assessment of vascular involvement by pancreatic malignancy.
  
  
  METHODS
  For 44 patients with known pancreatic malignancy a total of 56 arterial phase helical CT scans were obtained. Targeted pancreatic imaging was performed, and reformatted images were generated. Axial source images, reformatted images, and the combination of axial and reformatted images were interpreted independently by three observers. The observers graded the celiac axis, common and proper hepatic, splenic, gastroduodenal, and superior mesenteric arteries for tumor involvement. Grades of vascular involvement were compared by intra- and interobserver variability analyses.
  
  
  RESULTS
  Intraobserver agreement averaged over five vessels was good between the axial and combined techniques for each individual observer (0.64 < or kappa < or = 0.66), but intraobserver agreement was poor between the axial and reformatted (kappa = 0.17 and kappa = 0.31, respectively) and the reformatted and combined techniques (kappa = 0.31 and kappa = 0.38, respectively) for two observers. For grading of vascular involvement in each vessel, intraobserver agreement was good to excellent between the axial and combined techniques (0.48 or = kappa < or = 0.82). Interobserver agreement averaged over five vessels was poor for imaging techniques except between observer 2 and observer 3 on the axial (kappa = 0.47) and combined techniques (kappa = 0.47). For grading of vascular involvement in each vessel, interobserver agreement for reformatted technique was poor (0.09 < or = kappa < or = 0.40).
  
  
  CONCLUSIONS
  Multiplanar and volume-rendered techniques showed the highest intra- and interobserver variability in grading vascular involvement by pancreatic malignancy. These images should be used in combination with routine axial images to decrease observer variability.
authors.affiliation: Department of Radiology, Ewha Womans University Mok Dong Hospital, 911-1 Mok-Dong, Yang-Cheon-Ku, Seoul, 158-710 South Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Baek
authors.forename: D H
authors.initials: DH
authors.lastname: Sheafor
authors.forename: M T
authors.initials: MT
authors.lastname: Keogan
authors.forename: D M
authors.initials: DM
authors.lastname: DeLong
authors.forename: R C
authors.initials: RC
authors.lastname: Nelson
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D009361:Neoplasm Invasiveness; D015588:Observer Variation; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods; D019043:Vascular Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology