Dispersion of a Short ASL Bolus Along the Arterial Tree

Matthias Gnther¹

In ASL, the inflow of labeled blood is usually modeled by assuming a single arrival time of the bolus in the voxel under consideration. However, it was shown that models, which assume a distribution of arrival times can fit some signal curves more accurately. The goal of this work is to show how a labeled blood bolus is dispersed while traveling down the arterial tree. A short bolus of 500ms length is used and sampled with 100ms temporal resolution. The broadening of this bolus is approximately proportional to the bolus arrival time. This tool might be a sensitive marker to detect local changes of hemodynamics.