title: Abdominal aortic aneurysm measurements for endovascular repair: intra- and interobserver variability of CT measurements.
abstract: OBJECTIVE
  to evaluate the intra- and interobserver variability in measurements of the aorta and iliac arteries in patients with abdominal aortic aneurysms (AAAs) considered for endovascular repair using computed tomography angiography (CTA).
  
  
  METHODS
  the diameter of the neck, aneurysm, right and left iliac artery were measured by 5 observers in 10 consecutive patients. Measurements were performed on hard copy using a ruler and on a workstation using an electronic caliper.
  
  
  RESULTS
  the intraobserver variability showed a decrease going from hard copy to workstation in the standard deviation of the differences of the paired observations for the neck from 3.54 mm to 1.18 mm; for the aorta from 4.16 to 1.72 mm; for the right iliac from 1.87 to 1.01 mm; for the left iliac from 2.07 to 0.87 mm. The interobserver variability showed a similar decrease for the neck in all ten pairs of observers; for the aorta in two, for the right iliac and left iliac in five. However, the difference between observers regularly exceeded 2 mm.
  
  
  CONCLUSIONS
  the use of a workstation and electronic calipers results in lower intra- and interobserver variability. However, the results still show a clinically relevant difference between the observers. Therefore, it is necessary to develop an automatic observer-independent measurement technique.
authors.affiliation: Department of Radiology, Leiden University Medical Centre, Leiden, The Netherlands.
authors.forename: N J
authors.initials: NJ
authors.lastname: Aarts
authors.forename: G W
authors.initials: GW
authors.lastname: Schurink
authors.forename: L J
authors.initials: LJ
authors.lastname: Schultze Kool
authors.forename: P J
authors.initials: PJ
authors.lastname: Bode
authors.forename: J M
authors.initials: JM
authors.lastname: van Baalen
authors.forename: J
authors.initials: J
authors.lastname: Hermans
authors.forename: J H
authors.initials: JH
authors.lastname: van Bockel
mesh_terms: D000792:Angiography / Q000379:methods*; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000601:surgery; D003287:Contrast Media / Q000008:administration & dosage; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging*; D007275:Injections, Intravenous; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives; D015588:Observer Variation; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D014656:Vascular Surgical Procedures
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol