Measuring Cerebral Blood Flow: Methods

This chapter describes practical methods to measure cerebral blood flow. For SPECT, the diffusible tracers Xe-133 and I-123 IMP are described. These are used for quantitative measurements of cerebral blood flow to evaluate the necessity for treatment in stroke. Chemical microsphere tracers labeled with Tc-99m are widely used for semiquantitative cerebral blood flow measurements. In PET, quantitative cerebral blood flow and metabolism can be measured using O-15-labeled gases and FDG. Neural transmission and abnormal protein deposits are examined for degenerative diseases using some newly developed tracers. This chapter also discusses methods that do not use RI tracers. These include cold xenon as a diffusible tracer with CT, arterial spin-labeling with MRI, and contrast agents as nondiffusible tracers with both CT and MRI. In addition, several experimental methods for animals using laser Doppler flowmetry (LDF), laser speckle imaging (LSI) and two-photon microscopy are introduced.