Journal of Ultrasound in Medicine, Vol 14, Issue 6 463-466, Copyright © 1995 by American Institute of Ultrasound in Medicine
Variability in measurement of central retinal artery velocity using color Doppler imaging
K. J. Dennis, R. D. Dixon, F. Winsberg, J. T. Ernest and T. K. Goldstick
Department of Ophthalmology, University of Chicago, Illinois 60637, USA.
The purpose of our study was to test the reproducibility of the central
retinal artery velocity measurements as made by color Doppler imaging and
pulsed Doppler spectral tracings and to define the optimal location for
placement of the sample volume. We used the Siemens Quantum (Q 2000) with a
7.5 MHz linear array transducer to identify the central retinal artery and
record its velocity. Eleven eyes from 11 normal subjects were evaluated for
the peak systolic central retinal artery velocity in two positions, the
first posteriorly in the optic nerve at an average of 3.56 mm from the
surface of the optic disc and the second at an average of 1.76 mm from the
surface of the optic disc. We then used a color-flow threshold to identify
and record the point of maximal velocity. The range of systolic velocities
in the 11 eyes was from 5.85 to 22.51 cm/sec. The peak systolic velocity
posteriorly in the optic nerve averaged 8.16 cm/sec, whereas near the
surface of the optic disc the velocity averaged 13.89 cm/sec (70.2%
higher). Using the color flow threshold method, the maximal velocity was
located at an average of 1.98 mm from the surface of the optic disc. Our
data show that large differences exist in measured central retinal artery
velocity that depend on the location of the measurement, and that
color-flow thresholding is valuable in locating the optimal location for
pulsed Doppler spectral recording.
