title: Reproducibility of semi-automatic coronary plaque quantification in coronary CT angiography with sub-mSv radiation dose.
abstract: BACKGROUND
  Coronary computed tomographic angiography (CTA) can characterize coronary atherosclerotic plaque components as calcified and non-calcified. Quantitative measurements of coronary plaque burden by coronary CTA may play a role in serial studies to determine disease progression or response to medical therapies. The reproducibility from repeated assessment of such quantitative measurements from low-radiation dose coronary CTA has not been previously assessed.
  
  
  OBJECTIVE
  To evaluate the interscan, interobserver and intraobserver reproducibility for coronary plaque volume assessment using semi-automatic plaque analyses algorithm in low radiation dose coronary CTA.
  
  
  METHODS
  In 50 consecutive patients undergoing two 128-slice dual source CT scans within 12 days with a mean radiation dose of 0.7 mSv per coronary CTA, the interscan, interobserver and intraobserver reproducibility of coronary plaque assessment using validated software (AutoPlaq) were evaluated.
  
  
  RESULTS
  Interscan, interobserver and intraobserver agreement for non-calcified and calcified plaque volumes were excellent (Spearman rho 0.87-0.99). Interscan mean percentage difference in non-calcified and calcified plaque volumes were 0.1% (p = 0.8) and 1.9% (p = 0.19) with limits of agreement of ±11% and ±48.5%; per inter- and intraobserver mean percentage differences were 0.1% (p = 0.25) and 0.3% (p = 0.001), and 0.3% (p = 0.33) and 0.4% (p = 0.59) with limits of agreement of ±7% and ±32.9%, and ±6.6% and ±32.1%, respectively.
  
  
  CONCLUSIONS
  A semi-automatic plaque assessment algorithm in repeated low radiation dose coronary CTA allows for high reproducibility of coronary plaque characterization and quantification measures.
authors.affiliation: Aarhus University Hospital, Department of Cardiology, Denmark; Lillebaelt Hospital Vejle, Department of Cardiology, Denmark; Odense University Hospital, Department of Cardiology, Denmark. Electronic address: kristianovrehus@hotmail.com.
authors.forename: Kristian Altern
authors.initials: KA
authors.lastname: Øvrehus
authors.affiliation: Erlangen University Hospital, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Schuhbaeck
authors.affiliation: Erlangen University Hospital, Germany.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Marwan
authors.affiliation: Erlangen University Hospital, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.affiliation: Cedars Sinai Medical Center, Los Angeles, USA.
authors.forename: Bjarne Linde
authors.initials: BL
authors.lastname: Nørgaard
authors.affiliation: Cedars Sinai Medical Center, Los Angeles, USA.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.affiliation: Cedars Sinai Medical Center, Los Angeles, USA.
authors.forename: Damini
authors.initials: D
authors.lastname: Dey
mesh_terms: D000368:Aged; D000465:Algorithms; D001331:Automation; D000072226:Computed Tomography Angiography; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D058226:Plaque, Atherosclerotic; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D012984:Software
keywords: Coronary CT angiography; Coronary artery disease; Coronary plaque imaging