Arterial spin labeling in space and time : new MRI sequences to probe cerebral hemodynamics

In this thesis I have described the introduction and validation of a new spatially non-selective arterial spin labeling (SNS-ASL) method in healthy subjects. Acceleration selective ASL (AccASL) was compared with pseudo continuous ASL (pCASL), a traditional ASL method, as well as other spatially non-selective ASL methods (velocity selective ASL, as introduced by Wong et al with two velocity-selective blocks, and using only a single labeling module), and with [15O]-H2O PET as the gold standard for brain perfusion imaging. By combining an AccASL with VSASL labeling module, the location of label origin in the vascular tree was assessed. Furthermore, time-encoded pCASL was explored in combination with SNS-ASL labeling modules to obtain insight into labeling at multiple post labeling delays (PLD). Finally, te-pCASL was combined with T2-Relaxation-under-Spin-Tagging (TRUST) to provide a time efficient method to distinguish spin compartments based on their T2-values.