title: Fractional moving blood volume: estimation with power Doppler US.
abstract: OBJECTIVE
  To estimate the fraction of moving blood in tissue with power Doppler ultrasound (US).
  
  
  METHODS
  Power Doppler US measurements of moving scatterers in a flow tube were made as a function of successive dilutions of the perfusate. Measurements were normalized relative to the maximum Doppler power in the center of the flow tube at the highest concentration and were used to calculate the fractional dilution of the perfusate for each run with each dilution used to represent increasing amounts of non-moving soft tissue in the sample volume. The technique was also applied to two clinical examples.
  
  
  RESULTS
  Successive dilutions of the perfusate in the flow experiment showed a monotonic, linear decrease in the Doppler power as a function of dilution.
  
  
  CONCLUSIONS
  The power Doppler US technique has the potential to more accurately estimate alterations in blood flow and has the advantage of being a continuous parameter that can be depth normalized.
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor 48109, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Rubin
authors.forename: R S
authors.initials: RS
authors.lastname: Adler
authors.forename: J B
authors.initials: JB
authors.lastname: Fowlkes
authors.forename: S
authors.initials: S
authors.lastname: Spratt
authors.forename: J E
authors.initials: JE
authors.lastname: Pallister
authors.forename: J F
authors.initials: JF
authors.lastname: Chen
authors.forename: P L
authors.initials: PL
authors.lastname: Carson
mesh_terms: D001775:Blood Circulation; D001810:Blood Volume; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D012079:Renal Circulation; D018615:Ultrasonography, Doppler, Color