Signal analysis of noninvasive Xenon-133 cerebral blood flow measurements.

An anatomical model in conjunction with experimentally determined absorption data provides a framework to simulate signals as obtained from the noninvasive Xenon-133 cerebral blood flow technique. The contribution of individual tissue compartments to the total signal as well as the effect on the computed results were investigated under normal conditions. The introduction of physiological abnormalities into the model allowed the determination of sensitivity of the technique with respect to size, position, and perfusion level of the lesion. In addition, effects of cross-talk between hemispheres and signal overlap of adjacent detectors were quantified. It was found that the change of externally measured blood flow is proportional to the decrement/increment of flow in the lesion. Contrary to earlier reports, the effects of cross-talk and signal overlap were not found to be serious limitations in identifying lesions.