title: Measurement of maximum diameter of native abdominal aortic aneurysm by angio-CT: reproducibility is better with the semi-automated method.
abstract: OBJECTIVE
  We sought to identify the technique yielding the best reproducibility from among various measures of native maximum abdominal aortic aneurysm (AAA) diameter with computed tomography angiography (CTA).
  
  
  METHODS
  Ten parameters of maximum diameter in 68 native AAA were measured double-blind by three radiologists on orthogonal planes, curved multiplanar reconstructions, and, finally, using semi-automated software. The semi-automated software creates the AAA lumen centreline and automatically provides cross sections perpendicular to this centreline. The maximum diameter in any direction is automatically calculated once the slice of interest has been selected. Intra- and inter-observer reproducibility and discordance >5 mm were analysed.
  
  
  RESULTS
  Intra-observer reproducibility was high. The limits of agreement were within the clinically accepted range [-5; +5 mm] in 27/30 (90%) comparisons. The method common to all three observers that yielded the lowest values was the semi-automated method. Inter-observer reproducibility was poorer. The limits were outside the clinically accepted range in 26/30 (87%) comparisons. The semi-automated method led to lower intra- (0%) and inter-observer (5.88%) discordances rates.
  
  
  CONCLUSIONS
  Even using precise methodology, the reproducibility of maximum diameter measurements of native AAA on CTA may exceed recommended thresholds. The semi-automatic method yielded the lower discordance rates and provided a more relevant anatomical approach for measuring the maximum diameter of an AAA.
authors.affiliation: Vascular Medicine, University Hospital Reims, Hôpital Robert Debré, Reims, France; Department of Radiology, University Hospital Reims, Hôpital Robert Debré, Reims, France.
authors.forename: C
authors.initials: C
authors.lastname: Mora
authors.affiliation: Department of Radiology, University Hospital Reims, Hôpital Robert Debré, Reims, France.
authors.forename: C
authors.initials: C
authors.lastname: Marcus
authors.affiliation: Clinical Research Unit, University Hospital Reims, Reims, France.
authors.forename: C
authors.initials: C
authors.lastname: Barbe
authors.affiliation: Department of Cardiology, University Hospital Besançon, Besançon, France.
authors.forename: F
authors.initials: F
authors.lastname: Ecarnot
authors.affiliation: Vascular Medicine, University Hospital Reims, Hôpital Robert Debré, Reims, France; Department of Internal Medicine and Vascular Medicine, Hospices Civils de Lyon, University Hospital Edouard Herriot, Lyon, France; Claude Bernard Lyon 1 University, Lyon, France. Electronic address: anne.long@chu-lyon.fr.
authors.forename: A
authors.initials: A
authors.lastname: Long
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D057205:Automation, Laboratory; D006801:Humans; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012984:Software
keywords: Abdominal aortic aneurysm; Computed tomography; Reproducibility