Emission tomographic measurement of local cerebral blood flow in humans by an in vivo autoradiographic strategy

Abstract

An in vivo autoradiographic strategy is described for the measurement of local cerebral blood flow in humans by positron emission tomography, based on an application of the single-compartment model originally proposed by Kety. A variety of factors are considered upon which the successful quantitation of local blood flow depends. These factors include the mode of tracer administration and the definition of the arterial input function; the choice of scan parameters to assure unique and sensitive values of flow throughout the physiological range of interest; the influence of these parameters on the stability and signal/noise characteristics of the computed flow; the error introduced by the presence of heterogeneity of flow within a volume element; and factors related to the choice of the radiotracer itself. The in vivo autoradiographic method is compared to an alternative local cerebral blood flow method employing continuous inhalation of oxygen-15-labeled carbon dioxide. The general relevance of these issues to all local blood flow methods intended for emission tomographic application is emphasized.

Error Analysis of a Quantitative Cerebral Blood Flow Measurement Using H215O Autoradiography and Positron Emission Tomography, with Respect to the Dispersion of the Input Function

“…The CBF obtained by H2150 autoradiography fol lowing a single breath of C1502 was significantly greater than that obtained in the steady-state method (Kanno et aL, 1984). (b) The CBF values obtained by H2150 autoradiography changed as a function of the accumulation time (Raichle et al, 1983;Ginsberg et aL, 1984). (c) The partition coeffi cient obtained by an H2150 single-injection study was unexpectedly small (Depresseux et aL, 1983;Huang et al, 1983).…”

“…(c) The partition coeffi cient obtained by an H2150 single-injection study was unexpectedly small (Depresseux et aL, 1983;Huang et al, 1983). Some of them interpreted these phenomena as an inaccuracy of the model, such as diffusion limit and/or smaller water-exchangeable volume (Huang et aL, 1983;Ginsberg et aL, 1984;Kanno et al, 1984).…”

Relative volume‐average murine tumor blood flow measurement via deuterium nuclear magnetic resonance spectroscopy

“…[ 31 (i.e., increasing a relative to b ) . Consequently, at high flow rates the change in Z(tl, t 2 ) for a fixed increment in flow decreases and can actually become negative for delayed and extended integration limits (23). Thus, to rationally select the integration limits ( t l , t2), the effect of tl and t2 on sensitivity to the shape of the arterial input function, the relationship between flow and I ( tl , t2), and the signal-to-noise ratio (SNR) in the NMR measurement were evaluated by computer simulation.…”