title: Aortic aneurysm volume calculation: effect of operator experience.
abstract: BACKGROUND
  We have successfully applied sequential volumetric analysis of abdominal aortic aneurysms to exclude endoleak in patients who have an aortic endostent. This study compared the effect of variable operator experience on volumetric calculation accuracy.
  
  
  METHODS
  Four operators with different experience levels calculated abdominal aneurysm volumes in 10 patients at two different times (>/= 1 week apart). The four reviewers were ranked as having a high level of experience (one full-time laboratory worker specializing in three dimensions with 3 years of experience), a moderate level of experience (one part-time laboratory worker specializing in three dimensions/computed tomographic technician with 1 year of part-time experience), and a low level of experience (two individuals taught volumetric measurements for the purposes of this study: a fellow in abdominal imaging and a computed tomographic technician). All volumes were calculated with a GE Advantage 4.0 workstation (General Electric, Waukesha, WI, USA).
  
  
  RESULTS
  Mean aneurysm volume and volume difference between two measurements were calculated for four operators. The average (standard deviation) percent volume differences were 1.2% (0.2%) for the experienced reader, 3.2% (0.3%) for the moderately experienced reader, and 6.0% (1.0%) and 5.8% (1.1%) for the two readers with light experience. Differences between averages were statistically significant (p < 0.005).
  
  
  CONCLUSIONS
  We have defined a percent margin of error for aortic aneurysm volume measurement and have shown a direct correlate to level of experience. Diagnosis of endoleak based on aneurysm volume enlargement on serial scans needs to account for the level of operator experience.
authors.affiliation: Department of Radiology, University of Wisconsin Hospital and Clinics, 600 Highland Avenue, Madison, WI 53792-3252, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: Caldwell
authors.forename: K A
authors.initials: KA
authors.lastname: Pulfer
authors.forename: G R
authors.initials: GR
authors.lastname: Jaggi
authors.forename: H L
authors.initials: HL
authors.lastname: Knuteson
authors.forename: J P
authors.initials: JP
authors.lastname: Fine
authors.forename: M A
authors.initials: MA
authors.lastname: Pozniak
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000473:pathology*; D006801:Humans; D015588:Observer Variation; D013647:Task Performance and Analysis; D014654:Vascular Patency