Radiology, Vol 151, 627-633, Copyright © 1984 by Radiological Society of North America
Glomerular filtration rate in children: determination from the Tc-99m- DTPA renogram
RM Shore, SA Koff, M Mentser, JR Hayes, SP Smith, JP Smith and RW Chesney
Analysis of the Tc-99m-DTPA renogram is usually limited to calculating the
relative function of each kidney. To develop a method to determine the
absolute glomerular filtration rate (GFR), various methods of analyzing the
renogram were examined to determine which gave the best correlation with
GFR. That regression could then be used to predict GFR without the need for
blood samples. Fifty children were studied using Tc-99m-DTPA renograms and
GFR measured simultaneously by plasma disappearance. The renogram variables
were adjusted for detector sensitivity and for dose divided by weight,
which was used as an index of plasma concentration. GFR correlated better
with the slope of the second phase than with the area under the renogram
curve. For the best correlation with GFR (using background subtraction and
depth correction) r = .971 and the mean residual = 4.8 ml/min. For GFR
normalized for body surface area (using background subtraction and no depth
correction) r = .954 and the mean residual = 9.1 ml/min/1.73 m2. This
method can accurately estimate GFR from the renogram in children.
