Combination of Dynamic and Integral Methods for Generating Reproducible Functional CBF Images

Abstract

A new method to measure regional CBF is presented, applying both dynamic and integral analyses to a dynamic sequence of positron emission tomographic scans collected during and following the administration of H₂¹⁵O (inhalation of C¹⁵O₂). The dynamic analysis is used to correct continuously monitored arterial whole-blood activity for delay and dispersion relative to tissue scans. An integral analysis including corrections for this delay and dispersion is then used to calculate CBF on a pixel-by-pixel basis. Normal values and reproducibility over a 2-h period are presented, together with the results of validation and simulation studies. The results indicate that the single–tissue compartment model adequately describes the distribution of H₂¹⁵O in the brain, without recourse to postulating a nonexchanging water pool.