title: Reproducibility of semi-automated measurement of carotid stenosis on CTA.
abstract: OBJECTIVE
  To compare the reproducibility of semi-automated vessel analysis software to manual measurement of carotid artery stenosis on computed tomography angiography (CTA).
  
  
  METHODS
  Two observers separately analyzed 81 carotid artery CTAs using semi-automated vessel analysis software according to a blinded protocol. The software measured the narrowest stenosis in millimeters (mm), distal internal carotid artery (ICA) in mm, and calculated percent stenosis based on NASCET criteria. One observer performed this task twice on each carotid, the second analysis delayed two months in order to mitigate recall bias. Two other observers manually measured the narrowest stenosis in mm, distal ICA in mm, and calculated NASCET percent stenosis in a blinded fashion. Correlation coefficients were calculated for each group comparing the narrowest stenosis in mm, distal ICA in mm, and NASCET percent stenosis.
  
  
  RESULTS
  The semi-automated vessel analysis software provided excellent intraobserver correlation for narrowest stenosis in mm, distal ICA in mm, and NACSET percent stenosis (Pearson correlation coefficients of 0.985, 0.954, and 0.977 respectively). The semi-automated vessel analysis software provided excellent interobserver correlation (0.925, 0.881, and 0.892 respectively). The interobserver correlation for manual measurement was good (0.595, 0.625, and 0.555 respectively). There was a statistically significant difference in the interobserver correlation between the semi-automated vessel analysis software observers and the manual measurement observers (P < 0.001).
  
  
  CONCLUSIONS
  Semi-automated vessel analysis software is a highly reproducible method of quantifying carotid artery stenosis on CTA. In this study, semi-automated vessel analysis software determination of carotid stenosis was shown to be more reproducible than manual measurement.
authors: Division of Neuroradiology, Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
authors: Jeremy H
authors: JH
authors: White
authors: Eric S
authors: ES
authors: Bartlett
authors: Aditya
authors: A
authors: Bharatha
authors: Richard I
authors: RI
authors: Aviv
authors: Allan J
authors: AJ
authors: Fox
authors: Andrew L
authors: AL
authors: Thompson
authors: Richard
authors: R
authors: Bitar
authors: Sean P
authors: SP
authors: Symons
mesh_terms: D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000532:radiotherapy*; D001330:Electronic Data Processing / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012984:Software; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed