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.