What Is the Detectability of Arterial Transit Times in Pulsed Arterial Spin Labeling (PASL): A Simulation and Empirical Study

Bradley J. MacIntosh¹, Nicola Filippini¹, Manus J. Donahue¹, Michael A. Chappell¹, Clare E. Mackay¹, Peter Jezzard¹

Arterial spin labeling (ASL) is a versatile perfusion MRI technique. It has long been known however that CBF estimates are highly sensitive to the arterial transit time. In the current study we investigate the detectability of ATT and assess the value of mapping ATT across the brain as a complementary imaging metric to CBF. Simulations were also performed at 3 T to determine the detectability of CBF and ATT over a range of simulated transit times and SNR conditions. ATT maps were found to be reliable over a range of physiological scenarios. ATT varied across the brain according to the vascular territories. Sex differences were also highly significant, with women having a shorter ATT compare to men.