Observer experience improves reproducibility of color Doppler sonography of orbital blood vessels.

Purpose: The study investigated the reproducibility of orbital blood flow measurements with color Doppler imaging (CDI) at different stages of observer experience.

Methods: The subjects were 31 healthy volunteers and 2 sequential groups of 25 glaucoma patients each. Repeated blood flow measurements (usually 3 sets) in orbital vessels (ophthalmic artery, short posterior ciliary arteries, central retinal artery, and central retinal vein) were performed by the same observer in a single session in each subject.

Results: The parameters with the best reproducibility were the resistance index (mean coefficient of variation [COV], 3.3-8.8%), the peak systolic velocity (mean COV, 6.9-13.7%), the time-averaged velocity (mean COV, 7.2-16.0%), and the systolic acceleration time (mean COV, 8.8-12.3%). The mean COV was greater (9.9-20.3%) for the other arterial flow parameters (end-diastolic velocity and systolic acceleration) and for the venous flow velocities (maximum and minimum). The COVs of the parameters were improved by 20-40% as the observer became more experienced in ophthalmic CDI.

Conclusions: We confirm the general reliability of CDI measurements in orbital vessels and show that observer experience improves reproducibility. It appears, however, that observer performance in these measurements is vessel specific.