title: Limitations of ultrasonography in surveillance of small abdominal aortic aneurysms.
abstract: The repeatability, observer bias and instrument bias of aortic diameter measurement by ultrasonography, were investigated in ten patients with small (3-6 cm by computed tomography) infrarenal abdominal aortic aneurysm. The repeatability of maximum aortic diameter measurement by ultrasonography was much better for anterior-posterior than transverse diameter, with coefficients of repeatability 3.0-7.5 mm and 10-15 mm respectively. The repeatability of suprarenal aortic diameter measurement was poor. Surprisingly, maximum diameter using ultrasonography was larger than that using computed tomography, the difference being least for anterior-posterior measurements. At best a single, experienced observer, using the same instrument may provide aortic diameters using ultrasonography accurate to within 5 mm, but more commonly such aortic diameter is only accurate to within 8 mm.
authors.affiliation: Department of Surgery, Charing Cross and Westminster Medical School, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Ellis
authors.forename: J T
authors.initials: JT
authors.lastname: Powell
authors.forename: R M
authors.initials: RM
authors.lastname: Greenhalgh
mesh_terms: D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000473:pathology; D001014:Aortic Aneurysm / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D015588:Observer Variation; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography