title: Reproducibility of abdominal aortic aneurysm diameter measurement and growth evaluation on axial and multiplanar computed tomography reformations.
abstract: OBJECTIVE
  To compare different methods measuring abdominal aortic aneurysm (AAA) maximal diameter (Dmax) and its progression on multidetector computed tomography (MDCT) scan.
  
  
  METHODS
  Forty AAA patients with two MDCT scans acquired at different times (baseline and follow-up) were included. Three observers measured AAA diameters by seven different methods: on axial images (anteroposterior, transverse, maximal, and short-axis views) and on multiplanar reformation (MPR) images (coronal, sagittal, and orthogonal views). Diameter measurement and progression were compared over time for the seven methods. Reproducibility of measurement methods was assessed by intraclass correlation coefficient (ICC) and Bland-Altman analysis.
  
  
  RESULTS
  Dmax, as measured on axial slices at baseline and follow-up (FU) MDCTs, was greater than that measured using the orthogonal method (p = 0.046 for baseline and 0.028 for FU), whereas Dmax measured with the orthogonal method was greater those using all other measurement methods (p-value range: <0.0001-0.03) but anteroposterior diameter (p = 0.18 baseline and 0.10 FU). The greatest interobserver ICCs were obtained for the orthogonal and transverse methods (0.972) at baseline and for the orthogonal and sagittal MPR images at FU (0.973 and 0.977). Interobserver ICC of the orthogonal method to document AAA progression was greater (ICC = 0.833) than measurements taken on axial images (ICC = 0.662-0.780) and single-plane MPR images (0.772-0.817).
  
  
  CONCLUSIONS
  AAA Dmax measured on MDCT axial slices overestimates aneurysm size. Diameter as measured by the orthogonal method is more reproducible, especially to document AAA progression.
authors.affiliation: Department of Radiology, Centre Hospitalier de l'Université de Montreal, University of Montreal, QC, Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Dugas
authors.forename: Eric
authors.initials: E
authors.lastname: Therasse
authors.forename: Claude
authors.initials: C
authors.lastname: Kauffmann
authors.forename: An
authors.initials: A
authors.lastname: Tang
authors.forename: Stephane
authors.initials: S
authors.lastname: Elkouri
authors.forename: Anna
authors.initials: A
authors.lastname: Nozza
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Giroux
authors.forename: Vincent L
authors.initials: VL
authors.lastname: Oliva
authors.forename: Gilles
authors.initials: G
authors.lastname: Soulez
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*