title: Comparative in-vitro validation of eight first- and second-generation quantitative coronary angiography systems.
abstract: BACKGROUND
  It is known that first-generation quantitative coronary angiography (QCA) systems overestimate small vessel sizes owing to the point-spread function of the respective X-ray imaging chain. With second-generation systems new algorithms were introduced to correct for this source of error.
  
  
  OBJECTIVE
  To evaluate the efficiency of the modified contour detection algorithms.
  
  
  METHODS
  Six second-generation QCA systems (CMS, QANSAD, AWOS, CAAS II, Cardio 500, and Angioimage) were validated and compared with first-generation systems (CAAS and ARTREK). By using an arterial phantom consisting of stenotic and nonstenotic glass tubes (of diameters 0.5-5.0 mm) the accuracy and precision of each analysis system, as well as their additional accuracy and precision values for phantom diameters < or = 1.0 mm were determined.
  
  
  RESULTS
  All systems had high accuracy and precision values, but first-generation systems overestimated small vessel diameters. With second-generation systems a significantly improved accuracy in the submillimeter range (an accuracy within +/-0.028 mm) was obtained. This improvement was accompanied by a moderate reduction in precision in the submillimeter range.
  
  
  CONCLUSIONS
  The new algorithms of the second-generation QCA systems allow accurate and reliable measurements of small coronary dimensions and, therefore, precise analysis of coronary stenoses of moderate-to-high grade seems feasible with the improved accuracy of the new systems.
authors.affiliation: Department of Cardiology, German Heart Center Munich, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Hausleiter
authors.forename: S
authors.initials: S
authors.lastname: Jost
authors.forename: C W
authors.initials: CW
authors.lastname: Nolte
authors.forename: J
authors.initials: J
authors.lastname: Dirschinger
authors.forename: A
authors.initials: A
authors.lastname: Kastrati
authors.forename: G M
authors.initials: GM
authors.lastname: Stiel
authors.forename: W
authors.initials: W
authors.lastname: Wunderlich
authors.forename: F
authors.initials: F
authors.lastname: Fischer
authors.forename: T
authors.initials: T
authors.lastname: Linderer
authors.forename: D
authors.initials: D
authors.lastname: Hausmann
authors.forename: A
authors.initials: A
authors.lastname: Schömig
mesh_terms: D000465:Algorithms; D017023:Coronary Angiography / Q000295:instrumentation*; D003327:Coronary Disease / Q000000981:diagnostic imaging; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D015203:Reproducibility of Results