Reproducibility of retrobulbar blood flow velocity measurements using two different colour Doppler imaging devices

Purpose To evaluate the intra and inter-operator reproducibility of color Doppler imaging (CDI) in assessing blood flow velocity in the ophthalmic (OA), central retinal (CRA) and short posterior ciliary arteries (SPCA) Methods The right eye of two group of 8 healthy volunteers was examined. Two radiologists and two ophthalmologists, divided into pairs, measured Peak Systolic Velocity (PSV), End-Diastolic Velocity (EDV) and Resistivity Index (RI) of each vessel using a different CDI device for each group. The concordance between two measurements was evaluated with Lin's concordance correlation coefficient (CCC) Results Globally very good degrees of intra-operator concordance were obtained for the PSV (0,859), EDV (0,834) and RI (0,859) of the OA. There was moderate concordance for PSV (0,574) and EDV (0,594) and good concordance for RI (0,694) for the CRA. Good degrees of concordance were obtained for the SPCA measurements. However inter-operator concordance was found globally poor Conclusion These data show that retrobulbar vessels CDI measurements are operator dependent. To increase the intra-operator and inter-operator concordance rules should be adopted for timing of the exam and probe position to minimize the pressure applied on the eye