Multicompartment analysis of blood flow and tissue perfusion employing D2O as a freely diffusible tracer: A novel deuterium NMR technique demonstrated via application with murine RIF‐1 tumors

Abstract

Deuterium NMR is employed in concert with multicompartment kinetic analysis for measurement of tissue blood flow and perfusion through a bolus administration of D₂O as a freely diffusible tracer. The traditional single-compartment and two-compartment in-parallel flow models with no tracer recirculation are briefly discussed. The two-compartment in-series flow model with recirculation is developed to account for reflow of the stable (slowly excreted) deuterium tracer. With this model a monoexponential tracer washout curve is predicted. The rate ofblood flow and tissue perfusion is readily extracted by three-parameter monoexponential analysis of the residue decay curve. A three-compartment model with recirculation, incorporating one compartment in-series with two compartments in-parallel, is developed for analysis of biexponential tracer washout curves. With this model the flow rates through the two in-parallel compartments (i.e., fast and slow) and the volume fractions of these two compartments are obtained by five-parameter biexponential analysis of the residue decay curve. Application of these multicompartment tracer-recirculation flow models is demonstrated with in situ determinations of murine RIF-1 tumor blood flow and tissue perfusion. The blood flow rates determined by deuterium NMR and analyzed by the multicompartment flow models agree well with those determined by others using radiolabels. A companion article (S.-G. Kim and J. J. H. Ackerman, Cancer Res. 48, 3449-3453, 1988) discusses in more depth the practical aspects of applying these multicompartment models to tumor blood flow measurement. © 1988 Academic Press, Inc.