Radiology, Vol 199, 165-169, Copyright © 1996 by Radiological Society of North America

ARTICLES

Renal resistive indexes: variability in Doppler US measurement in a healthy population

MT Keogan, MA Kliewer, BS Hertzberg, DM DeLong, RH Tupler and BA Carroll
Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA.

PURPOSE: To determine the variability in resistive index (RI) in normal kidneys, possible causes of variability, and consequences of reporting a single value. MATERIALS AND METHODS: Doppler ultrasound RI measurements were obtained in the upper, middle, and lower regions of 118 kidneys in 58 healthy subjects (aged 24-70 years; 35 women, 23 men) who subsequently underwent angiography. The effects of sampling a particular parenchymal region, vascular territory, or kidney were assessed. RESULTS: Kidney region, vascular territory, and right versus left kidney had no consistently significant effect (P < or = .05) on RI. Age had a statistically significant effect. RI readings were highly correlated with each other both within a subject and within a kidney. The probability that a single RI value would exceed 0.70 in a healthy 45-year-old subject was 6%; this decreased to 3% when three readings were averaged. CONCLUSION: The variability of RI measurements in a kidney suggests that a number of RI readings should be averaged before a single representative value is reported.

This article has been cited by other articles:

				M. E. Tublin, R. O. Bude, and J. F. Platt The Resistive Index in Renal Doppler Sonography: Where Do We Stand? Am. J. Roentgenol., April 1, 2003; 180(4): 885 - 892. [Full Text] [PDF]

				K. S. Aikimbaev, A. Canataroglu, S. Ozbek, and A. Usal Renal Vascular Resistance in Progressive Systemic Sclerosis: Evaluation with Duplex Doppler Ultrasound Angiology, October 1, 2001; 52(10): 697 - 701. [Abstract] [PDF]