The critical importance of convolution function (algorithm) selection in the measurement of blood flow in small blood...

In order to assess the capability for measuring blood flow in small vessels, the cardiac output was measured directly by either the microsphere reference sample technique or by obtaining blood samples simultaneously with the CT scan. The cardiac output was also measured in vivo by dynamic CT scanning and intravenous contrast as the indicator in an indicator dilution curve. Cardiac output was then calculated by two convolution back projection algorithms which optimized for either contrast or spatial resolution. The results of this study suggest that CT scanners are capable of accurately averaging intravascular changes in contrast density. Although it is good to optimize contrast resolution, the convolution back projection algorithm selected must have a pixel matrix which is much smaller than the vessel being analyzed.