A DECONVOLUTION METHOD FOR EVALUATING INDICATOR-DILUTION CURVES

Characteristics of blood Bow in tissue can be measured by administerin g an intravascular tracer and then deconvolving and analysing the resu lting indicator-dilution curves. Existing deconvolution methods are no t typically generalizable to a variety of tissues. We have developed a more general deconvolution method using simulated indicator-dilution data. This method involves filtering the Fourier transform of indicato r-dilution data with a modification of the Wiener filter, an adaptive deconvolution filter. Unlike the Wiener filter, this adaptive filter r equires no previous knowledge of the noise frequency spectrum; it is d erived by varying the magnitude of the noise spectrum until the oscill ations in the deconvolved data fall below an optimal value. The optima l value corresponds to the setting of the noise spectrum that allows t he most accurate and precise measurement of vascular characteristics f rom deconvolved data. Vascular characteristics measured in brain tissu es using this deconvolution method on actual indicator-dilution data w ere similar to established values. It should be possible to use this m ethod on time-concentration data collected from a variety of tissues u sing a number of different tracer measurement techniques, thereby allo wing the accurate characterization of vascular physiology.