EARLY SYSTOLE IN THE HEALTHY KIDNEY - VARIABILITY OF DOPPLER US WAVE-FORM PARAMETERS

PURPOSE: To determine the sampling variability of intrarenal Doppler u ltrasound (US) indexes of early systole in a screened population of he althy individuals. MATERIALS AND METHODS: Doppler US measurements were obtained in the superior, middle, and inferior regions of 132 kidneys in 66 healthy, potential kidney donors. All individuals subsequently underwent angiography. Systematic measurement differences and random e ffects were estimated for sampling from a particular parenchymal regio n, from a kidney in a subject, from an individual in a population, and from a vascular territory. RESULTS: Coefficients of variations ranged from 20% to 30%. Most (55%-66%) of the observed variation was attribu table to random differences between repeated measurements in the same kidney. No systematic variations attributable to kidney region, vascul ar territory, right versus left kidney, or subject age were found for acceleration time, acceleration, or waveform shape. Some evidence of f ixed variation between kidneys and between regions was found for peak systolic velocity, but the magnitude of this variation was small. Aver ages of repeated measurements may decrease the probability of exceedin g the normal threshold for acceleration but not for acceleration time. CONCLUSION: Measurements of Doppler parameters of the early systole h ave substantial intrinsic variability. Thus, caution is needed when in terpreting small changes in these measurements within a kidney or betw een individuals.