[Reproducibility of Doppler measurements in renal circulation]

Duplex ultrasonography is now used to detect renal artery (RA) stenosis, but measurement reproducibility was not assessed systematically in renal circulation. Our aim was to definite intra and inter-observer variabilities of initial acceleration time (AT), peak systolic velocity (SV), and end-diastolic velocity (DV) in RA. We examined 12 hypertensive patients with angiographically normal RA and 2 normotensives. During these 14 explorations, all measurement were made by the operator A twice, and 13/14 times by the operator B twice. A duplex ultrasound CGR Radius CF* device was used with a 3.75 MHz probe. Once the RA spotted by color imaging, AT, SV, DV were measured by pulsed doppler aligning on arterial axis without angle correction with translumbar approach at different levels (distal trunk, hilus, sinus). SV intra-observer variabilities were for operator A on mean 30% at distal trunk, 3% at hilus, 4% at sinus; for B, there were respectively 16, 0, 2%. About DV, there were for A 3, 0, 1% and for B 2, 7, 0%. Reproducibility was worse about AT. SV inter-observer variabilities were 14, 2, 3%, for DV 13, 3, 2%, for AT 2, 6, 5%. Therefore indexes based on SV, DV, and AT with a less reproducibility may be used for screening or follow-up, but their diagnostic value is still to assess.