Messung der cerebralen Durchblutung mittels Elektronenstrahl-Computertomographie

Using electron beam computed tomography (EBCT) with short exposure time of 50 ms it is possible to study dynamic and functional processes in different organs e.g. the cerebral blood flow. After contrast agent injection the measurement of changing CT-values in selected regions in the first pass enables to calculate the cerebral blood flow in ml/100g/min. Based on the indicator dilution theory two new methods for measuring organ blood flow were developed. Although the input function is not a Dirac impulse, the first blood flow equation calculates the values in the first pass using a washout correction algorithm. The second equation works with a so-called input function correction algorithm after deconvolution of the organ output function. A model was developed to describe the biological transfer functions from the injection site to the brain. After changing the input function (indicator injection time) amplitude-, time- and shape parameters of measured and simulated time-CT-value curves were investigated to validate the algorithms and to estimate the systematic failure of both blood flow equations. Using EBCT-technique cerebral blood flow values can be calculated globally and regionally as pseudocolor blood flow plots in 6 CT-slices.