Reproducibility of color Doppler imaging

Ingeborg Stalmans, Brent Siesky, Thierry Zeyen, Steffen Fieuws, Alon Harris

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Purpose: The aims of this study were: (1) to determine the intra-subject and inter-observer variability of color Doppler imaging (CDI) measurements and readings of the retrobulbar blood vessels, (2) to compare the difference in variability of CDI parameters in non-glaucomatous controls versus glaucoma patients, and (3) to provide calculations of minimum sample sizes for future CDI studies. Methods: Patients with normal tension glaucoma (n=28), primary open-angle glaucoma (n=19) and non-glaucomatous controls of comparable age (n=22) underwent CDI on two occasions 1 month apart. Variability in CDI parameters was quantified using (within-subject) coefficients of variation. Based on this variability, minimum sample sizes were calculated to guide the design of future studies comparing CDI between and within groups. Results: In general, within-subject coefficients of variation for measurements 1 month apart were comparable to previously reported short-term variations. Variability was higher in glaucoma patients than in non-glaucomatous controls. The minimum sample size required for glaucomatous study populations is larger than for non-glaucomatous controls. Smaller patient groups are required to detect change using the peak systolic blood flow velocities than using end diastolic velocities. Studies using a cross-over design require smaller sample sizes than studies with a pre-post or particularly parallel design. Conclusions: This study provides extensive information on long-term intra-subject variability of CDI measurements in non-glaucomatous controls as well as glaucoma patients. Moreover, sample size calculations are provided for studies involving glaucoma patients as well as non-glaucomatous individuals, using three different commonly used study designs.

Original languageEnglish
Pages (from-to)1531-1538
Number of pages8
JournalGraefe's Archive for Clinical and Experimental Ophthalmology
Volume247
Issue number11
DOIs
StatePublished - 2009

Fingerprint

Color
Sample Size
Glaucoma
Low Tension Glaucoma
Observer Variation
Blood Flow Velocity
Cross-Over Studies
Blood Vessels
Reading
Population

Keywords

  • Blood flow
  • Color doppler imaging
  • Glaucoma
  • Reproducibility

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Reproducibility of color Doppler imaging. / Stalmans, Ingeborg; Siesky, Brent; Zeyen, Thierry; Fieuws, Steffen; Harris, Alon.

In: Graefe's Archive for Clinical and Experimental Ophthalmology, Vol. 247, No. 11, 2009, p. 1531-1538.

Research output: Contribution to journalArticle

Stalmans, Ingeborg ; Siesky, Brent ; Zeyen, Thierry ; Fieuws, Steffen ; Harris, Alon. / Reproducibility of color Doppler imaging. In: Graefe's Archive for Clinical and Experimental Ophthalmology. 2009 ; Vol. 247, No. 11. pp. 1531-1538.
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