title: [Variations of Doppler blood flow parameters in central retinal artery in relation to position of sample volume].
abstract: OBJECTIVE
  To determine variability in measurements of Doppler blood flow parameters in central retinal artery in relation to sample volume location from the optic disc.
  
  
  METHODS
  Eighty central retinal arteries were examined using color Doppler ultrasonography in 40 healthy volunteers (22 female, 18 male), aged 45 +/- 9 with 7.5 MHz linear-array probe. The measurements of blood velocities and resistance indices in the arteries were obtained at points where distance from optic disc surface ranged from 1.5 mm to 6 mm.
  
  
  RESULTS
  Blood velocities increased significantly when sampled closer to the globe (r = -0.61, and r = -0.32 for peak-systolic and end-diastolic velocities, respectively). Mean peak-systolic velocities were 13.0 +/- 2.7 cm/s when distance 2.1 +/- 0.46 mm from optic disc, and 9.3 +/- 2.5 cm/s when distance 4.27 +/- 0.9 mm. Mean end-diastolic velocities were 4.3 +/- 1.2 cm/s and 3.6 +/- 1.1 cm/s, respectively. Resistance indices inclined to increase when the distance between the measurement site and the globe shortened. Resistance indices were 0.67 +/- 0.06 when measured closer to the globe and 0.60 +/- 0.06 when measured farther from it.
  
  
  CONCLUSIONS
  Position of sample volume in relation to optic disc has to be taken into account and defined if measurements of blood flow Doppler parameters of the central retinal artery are to be reproducible.
authors.affiliation: Zakładu Radiologii AM w Białymstoku.
authors.forename: A
authors.initials: A
authors.lastname: Ustymowicz
authors.forename: J
authors.initials: J
authors.lastname: Krejza
authors.forename: E
authors.initials: E
authors.lastname: Tarasów
authors.forename: Z
authors.initials: Z
authors.lastname: Mariak
authors.forename: E
authors.initials: E
authors.lastname: Proniewska-Skretek
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D005123:Eye / Q000033:anatomy & histology* / Q000098:blood supply*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000502:physiology; D012161:Retinal Artery / Q000000981:diagnostic imaging*; D018608:Ultrasonography, Doppler / Q000379:methods*