title: Radiologist variability in assessing the position of the cavoatrial junction on chest radiographs.
abstract: OBJECTIVE
  To assess the variability in identifying the cavoatrial junction (CAJ) on chest X-rays (CXRs) amongst radiologists.
  
  
  METHODS
  23 radiologists (13 consultants and 10 trainees) assessed 25 posteroanterior erect CXRs (including 8 duplicates) and marked the positions of the CAJ. Differences in the CAJ position both within and between observers were evaluated and reported as limits of agreement (LOA), repeatability coefficients (RCs) and intraclass correlation coefficients and were displayed graphically with Bland-Altman plots.
  
  
  RESULTS
  The mean difference for within-observer assessments was -0.2 cm (95% LOA, -1.5 to +1.1 cm) and between observers, it was -0.3 cm (95% LOA, -2.5 to +1.8 cm). Intraobserver RCs were marginally lower for consultants than for trainees (1.1 vs 1.5). RCs between observers were comparable (2.1 vs 2.2) for consultants and trainees, respectively.
  
  
  CONCLUSIONS
  This study detected a large interobserver variability of the CAJ position (up to 4.3 cm). This is a significant finding considering that the length of the superior vena cava is reported to be approximately 7 cm. We conclude that there is poor consensus regarding the CAJ position amongst radiologists.
  
  
  CONCLUSIONS
  No comparisons exist between radiologists in determining CAJ position from CXRs. This report provides evidence of the large observer variability amongst radiologists and adds to the discussion regarding the use of CXRs in validating catheter tip location systems.
authors.affiliation: 1 Department of Radiology, Royal Liverpool University Hospital NHS Trust, Liverpool, UK.
authors.forename: Tze Y
authors.initials: TY
authors.lastname: Chan
authors.affiliation: 2 Directorate of Radiography, University of Salford, Manchester, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: England
authors.affiliation: 1 Department of Radiology, Royal Liverpool University Hospital NHS Trust, Liverpool, UK.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Meredith
authors.affiliation: 1 Department of Radiology, Royal Liverpool University Hospital NHS Trust, Liverpool, UK.
authors.forename: Richard G
authors.initials: RG
authors.lastname: McWilliams
mesh_terms: D002405:Catheterization, Central Venous / Q000592:standards; D032921:Consensus; D003253:Consultants; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006801:Humans; D015588:Observer Variation; D013902:Radiography, Thoracic / Q000592:standards; D000072177:Radiologists / Q000592:standards*; D012189:Retrospective Studies; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging*