title: Clinical validation of a software for quantitative follow-up of abdominal aortic aneurysm maximal diameter and growth by CT angiography.
abstract: OBJECTIVE
  To compare the reproducibility and accuracy of abdominal aortic aneurysm (AAA) maximal diameter (D-max) measurements using segmentation software, with manual measurement on double-oblique MPR as a reference standard.
  
  
  METHODS
  The local Ethics Committee approved this study and waived informed consent. Forty patients (33 men, 7 women; mean age, 72 years, range, 49-86 years) had previously undergone two CT angiography (CTA) studies within 16 ± 8 months for follow-up of AAA ≥ 35 mm without previous treatment. The 80 studies were segmented twice using the software to calculate reproducibility of automatic D-max calculation on 3D models. Three radiologists reviewed the 80 studies and manually measured D-max on double-oblique MPR projections. Intra-observer and inter-observer reproducibility were calculated by intraclass correlation coefficient (ICC). Systematic errors were evaluated by linear regression and Bland-Altman analyses. Differences in D-max growth were analyzed with a paired Student's t-test.
  
  
  RESULTS
  The ICC for intra-observer reproducibility of D-max measurement was 0.992 (≥ 0.987) for the software and 0.985 (≥ 0.974) and 0.969 (≥ 0.948) for two radiologists. Inter-observer reproducibility was 0.979 (0.954-0.984) for the three radiologists. Mean absolute difference between semi-automated and manual D-max measurements was estimated at 1.1 ± 0.9 mm and never exceeded 5mm.
  
  
  CONCLUSIONS
  Semi-automated software measurement of AAA D-max is reproducible, accurate, and requires minimal operator intervention.
authors: Department of Medical Imaging, Hôpital Notre-Dame, Centre Hospitalier Universitaire de Montréal, 1560 Sherbrooke Est, Montréal, Québec, Canada H2L 4M1. claude.kauffmann@gmail.com
authors: Claude
authors: C
authors: Kauffmann
authors: An
authors: A
authors: Tang
authors: Alexandre
authors: A
authors: Dugas
authors: Éric
authors: É
authors: Therasse
authors: Vincent
authors: V
authors: Oliva
authors: Gilles
authors: G
authors: Soulez
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography / Q000379:methods*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D012986:Software Validation; D014057:Tomography, X-Ray Computed / Q000379:methods*