title: Quantification of arterial flow using digital subtraction angiography.
abstract: OBJECTIVE
  In this paper, a method for the estimation of arterial hemodynamic flow from x-ray video densitometry data is proposed and validated using an in vitro setup.
  
  
  METHODS
  The method is based on the acquisition of three-dimensional rotational angiography and digital subtraction angiography sequences. A modest contrast injection rate (between 1 and 4 ml/s) leads to a contrast density that is modulated by the cardiac cycle, which can be measured in the x-ray signal. An optical flow based approach is used to estimate the blood flow velocities from the cyclic phases in the x-ray signal.
  
  
  RESULTS
  The authors have validated this method in vitro, and present three clinical cases. The in vitro experiments compared the x-ray video densitometry results with the gold standard delivered by a flow meter. Linear correlation analysis and regression fitting showed that the ideal slope of 1 and intercept of 0 were contained within the 95 percentile confidence interval. The results show that a frame rate higher than 50 Hz allows measuring flows in the range of 2 ml/s to 6 ml/s within an accuracy of 5%.
  
  
  CONCLUSIONS
  The in vitro and clinical results indicate that it is feasible to estimate blood flow in routine interventional procedures. The availability of an x-ray based method for quantitative flow estimation is particularly clinically useful for intra-cranial applications, where other methods, such as ultrasound Doppler, are not available.
authors.affiliation: Philips Research, Paris 92150, France.
authors.forename: Odile
authors.initials: O
authors.lastname: Bonnefous
authors.forename: Vitor Mendes
authors.initials: VM
authors.lastname: Pereira
authors.forename: Rafik
authors.initials: R
authors.lastname: Ouared
authors.forename: Olivier
authors.initials: O
authors.lastname: Brina
authors.forename: Hans
authors.initials: H
authors.lastname: Aerts
authors.forename: Roel
authors.initials: R
authors.lastname: Hermans
authors.forename: Fred
authors.initials: F
authors.lastname: van Nijnatten
authors.forename: Jean
authors.initials: J
authors.lastname: Stawiaski
authors.forename: Daniel
authors.initials: D
authors.lastname: Ruijters
mesh_terms: D015901:Angiography, Digital Subtraction / Q000295:instrumentation*; D001158:Arteries / Q000502:physiology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000502:physiology; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D019047:Phantoms, Imaging