Deuterium NMR tissue perfusion measurements using the tracer uptake approach: I. Optimization of methods

This paper considers potential problems encountered when using the Kety app roach to measure perfusion in small laboratory animals with nuclear magneti c resonance (NMR) tracer uptake methods: a) the need to measure the arteria l input function (AIF) in each animal; b) sensitivity to perfusion heteroge neity; c) sensitivity to low signal-to-noise ratio (SNR); and d) influence of changes in the AIF. A method to estimate the AIF in rats is presented th at derives an AIF from the time course of a tracer passing through a caroti d chamber. The results of computer simulations indicate that a common AIF o btained in one set of animals can be used for perfusion estimations in anot her set of animals if the tracer is delivered as a dose and that optimal da ta analysis (fitting data vs, integration approach) is dictated by SNR and perfusion heterogeneity. Experimental strategies are suggested to minimize the effects of changes in the individual AIF that could distort perfusion e stimates. Magn Reson Med 42:42-52, 1999. (C) 1999 Wiley-Liss, Inc.