title: Measuring the abdominal aorta with ultrasonography and computed tomography - difference and variability.
abstract: OBJECTIVE
  The aim of this study was to estimate the agreement between ultrasonography (US) and computed tomography (CT) in the measurement of aortic diameter in subjects with and without abdominal aortic aneurysms (AAA).
  
  
  METHODS
  Sixty-one subjects were investigated, 33 with a diameter >30mm and 28 with a diameter <30mm. Difference and variabily anteroposterior (AP) and transverse (TR) diameters were analysed.
  
  
  RESULTS
  In non-aneurysmal aortas US gave larger AP: 2.8mm (95% CI 1.7-4.0) and TR: 3.8mm (2.3-5.3) diameter. In AAAs the mean diameter did not differ significantly. In non-aneurysmal aortas we expect 95% of differences to be <5.7mm in AP and <7.6mm in TR measurements. In aneurysmal aortas we expect 95% of differences to be <8.0mm in AP and <10.6mm in TR measurements.
  
  
  CONCLUSIONS
  The difference and variability between US and CT varies depends on the diameter of the aorta and how it is measured. These differences have importance for clinical practice and for research.
authors.affiliation: Department of Surgery Ornsköldsvik, County Hospital, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Wanhainen
authors.forename: D
authors.initials: D
authors.lastname: Bergqvist
authors.forename: M
authors.initials: M
authors.lastname: Björck
mesh_terms: D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008297:Male; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography