Modeling 15o-oxygen tracer data for estimating oxygen
consumption.
Deussen, Andreas, James B. Bassingthwaighte.
Center for Bioengineering WD-12, University of Washington, Seattle,
WA 98195
APStracts 2:0380H, 1995.
The most direct measure of oxidative tissue metabolism is the
conversion rate of oxygen to water via mitochondrial respiration. To
calculate oxygen consumption from the analysis of tissue residue
curves or outflow dilution curves following injection of labeled
oxygen one needs realistic mathematical models which account for
convection, diffusion and transformation in the tissue. A linear
three-region, axially distributed model accounts for intravascular
convection, penetration of capillary and parenchymal cell barriers
(using appropriate binding spaces to account for O2 binding to
hemoglobin and myoglobin), the metabolism to 15O-water in parenchymal
cells, and 15O-water transport into the venous effluent. Model
solutions fit residue and outflow dilution data obtained in an
isolated, red blood cell perfused rabbit heart preparation and give
estimates of the rate of oxygen consumption which are similar to
those obtained experimentally from the flow times the arterio-venous
differences in oxygen contents. The proposed application is for the
assessment of regional oxidative metabolism in vivo from tissue 15O
-residue curves obtained by positron emission tomography.
Received 22 March 1993; accepted in final form 10 August 1995.
APS Manuscript Number H259-3.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 15 September 1995.