title: In vitro simulation of the first technique for non-invasive measurement of volumetric ophthalmic artery blood flow in humans.
abstract: OBJECTIVE
  To evaluate the accuracy, reproducibility, and variability of volumetric flow measurements taken by color Doppler imaging ultrasound, using an in vitro "phantom" model to simulate the ophthalmic artery.
  
  
  METHODS
  An agar flow phantom with two wall-less lumens was constructed to simulate the ophthalmic artery. Velocity and volumetric flow measurements were taken for various flow rates and ultrasound probe positions. The measurements were analyzed for accuracy, reproducibility, and variability.
  
  
  RESULTS
  Velocity measurements were more accurate than flow measurements (8 of 24 vs 3 of 24 accurate trials). The average coefficient of variation for volumetric blood flow was 11.4% (n = 120). Volumetric flow significantly correlated with velocity (R(2) = 0.408, n = 600, P < .001). The highest correlation was achieved using the large lumen with the probe held at 75 degrees , offset to the flow (R(2) = 0.862, n = 75).
  
  
  CONCLUSIONS
  Based on an in vitro model, non-invasive color Doppler imaging recordings of volumetric flow measurements in the ophthalmic artery significantly correlated with velocity and higher correlations were found using the larger lumens, although the data showed a lack of high accuracy in measurements of flow and velocity.
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Brent
authors.initials: B
authors.lastname: Siesky
authors.forename: Alon
authors.initials: A
authors.lastname: Harris
authors.forename: Larry
authors.initials: L
authors.lastname: Kagemann
authors.forename: Danny
authors.initials: D
authors.lastname: Moore
authors.forename: Adam
authors.initials: A
authors.lastname: Werne
authors.forename: Clinton W
authors.initials: CW
authors.lastname: Sheets
authors.forename: Hanna J
authors.initials: HJ
authors.lastname: Garzozi
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D006801:Humans; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D018615:Ultrasonography, Doppler, Color / Q000295:instrumentation*