HIGH-RESOLUTION MEASUREMENT OF CEREBRAL BLOOD-FLOW USING INTRAVASCULAR TRACER BOLUS PASSAGES .1. MATHEMATICAL APPROACH AND STATISTICAL-ANALYSIS

The authors review the theoretical basis of determination of cerebral blood flow (CBF) using dynamic measurements of nondiffusible contrast agents, and demonstrate how parametric and nonparametric deconvolution techniques can be modified for the special requirements of CBF determ ination using dynamic MRI. Using Monte Carlo modelling, the use of sim ple, analytical residue models is shown to introduce large errors in f low estimates when actual, underlying vascular characteristics are not sufficiently described by the chosen function. The determination of t he shape of the residue function on a regional basis is shown to be po ssible only at high signal-to-noise ratio. Comparison of several nonpa rametric deconvolution techniques showed that a nonparametric deconvol ution technique (singular value decomposition) allows estimation of fl ow relatively independent of underlying vascular structure and volume even at low signal-to-noise ratio associated with pixel-by-pixel decon volution.