[Variability of ultrasonography velocity assessment of the carotid arteries].

PURPOSE

To assess the intraobserver variability of echoDoppler sonographic measurement of various carotid arteries parameters.

MATERIALS AND METHODS

Repeated bilateral carotid examinations were performed in ten healthy subjects, using three color-coded duplex ultrasound systems (two Acuson 128 XP, one ATL HDI 3000) and different linear probes. Each examination included two successive sets of measurements.

RESULTS

The resistive index values decreased from the proximal common carotid artery to the distal common carotid artery (p <10(-7)). According to the set of measurements and to the equipments considered, the range of mean absolute differences of the systolic peak velocity (PSV), the end diastolic velocity (EDV) values, the ICA/CCA PSV and PSV/EDV velocity ratios and the resistive index (RI) values were 8-16cm/s, 3-6cm/s, 0.08-0,15 and 0. 16-0.26, and 0.02-0.06 respectively. Standard deviations of the proportional differences of the RI and PSV measurements averaged respectively 6% and 15% and were always reduced by repeating the measurements. The use of similar ultrasound machines was not associated with a reduced variability.

CONCLUSION

The substantial variability of Doppler measurements in carotid arteries, even with the use of the same operator and similar machines could be reduced using "angle independent" parameters.