title: Test/Retest reproducibility of color Doppler imaging assessment of blood flow velocity in orbital vessels.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the test-retest reproducibility of measures of blood flow velocities using color Doppler imaging (CDI) in orbital arteries.
  
  
  METHODS
  Measures of peak systolic velocity, end-diastolic velocity, and resistive index were performed in a group of 15 normal tension glaucoma patients and in 15 healthy subjects using the Siemens Quantum 2000 CDI system with a 7.5 MHz linear probe. After each velocity measure in each vessel, the probe was removed and then replaced to repeat the measurement -2 min later.
  
  
  RESULTS
  For all subjects, the coefficients of reliability for measures of peak systolic velocity were 12% in the ophthalmic artery, 25% in the central retinal artery, and 19% in a short posterior ciliary artery. For end diastolic velocity, the coefficients were 6%, 11%, and 25%, respectively. The coefficients for resistive index were 4%, 11%, and 38%.
  
  
  CONCLUSIONS
  CDI produces highly reproducible measures in the ophthalmic artery. Measures in the central retinal artery are somewhat more variable but seem reasonably reproducible. Short posterior ciliary measurements were the most variable, suggesting that current methods for assessing these vessels may not be sufficiently reliable.
authors.affiliation: Departments of Ophthalmology, and Physiology and Biophysics, Indiana University School of Medicine, Indianapolis, Indiana, U.S.A., *Tennet Institute of Ophthalmology, Glasgow, Scotland, daggerWills Eye Hospital, Philadelphia, Pennsylvania, U.S.A., and double dagger;Medical Sciences Program, Indiana University, Bloomington, Indiana, U.S.A.
authors.forename: A
authors.initials: A
authors.lastname: Harris
authors.forename: T H
authors.initials: TH
authors.lastname: Williamson
authors.forename: B
authors.initials: B
authors.lastname: Martin
authors.forename: J A
authors.initials: JA
authors.lastname: Shoemaker
authors.forename: R C
authors.initials: RC
authors.lastname: Sergott
authors.forename: G L
authors.initials: GL
authors.lastname: Spaeth
authors.forename: J L
authors.initials: JL
authors.lastname: Katz