Non-invasive measurement of intrarenal blood flow distribution
using a kinetic model of renal 123i-hippuran handling.
Janssen, W. M. T., H. Beekhuis, R. De Bruin, P. E. De Jong, D. De
Zeeuw.
Departments of Medicine (Division of Nephrology), Nuclear Medicine,
and the Computer Center, University of Groningen, Groningen, The
Netherlands.
APStracts 2:0041F, 1995.
A new technique for non-invasive measurement of intrarenal blood flow
distribution over cortex and medulla is proposed. The technique
involves analysis of 123I-hippuran renography according to a kinetic
model, which describes the flow of 123I-hippuran from the heart
(input) through the renal cortex and medulla to the bladder (output).
The method is validated and compared to the standard microsphere
injection technique in anesthetized dogs. Changes in intrarenal blood
flow distribution were induced by infusion of placebo (n=6),
angiotensin-I (n=5), or atrial natriuretic factor (n=5). Baseline
percentage medullary blood flow in the left kidney was 12 +/- 1 % of
total renal blood flow measured with microspheres, and 15 +/- 1 %
with renography. During infusion of placebo medullary blood flow
decreased slightly as compared to baseline as measured with both
methods by 2 +/- 6 % (microspheres) and 1 +/- 8 % (renography).
Infusion of angiotensin-I caused a marked fall in medullary blood
flow by 42 +/- 11 % (microspheres) and 57 +/- 8 % (renography). In
contrast, infusion of atrial natriuretic factor caused a small rise
in medullary blood flow as measured with both methods (9 +/- 3 % and
12 +/- 11 %, respectively). The absolute and percent changes in
medullary blood flow measured with renography correlated with those
measured with microspheres (left kidney: r=0.67, p=0.005, and r=0.71,
p=0.003, respectively; right kidney r=0.62, p=0.01, and r=0.68,
p=0.004, respectively). We conclude that the proposed kinetic model
of renal 123I-hippuran handling can be used to measure changes in
intrarenal blood flow distribution, and because of its non-invasive
character, may be of use in clinical studies.
Received 14 June 1995; accepted in final form 7 March 1995.
APS Manuscript Number F206-3.
Article publication pending Am. J. Physiol. (Renal Fluid Electrolyte
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 4 April 1995.