Detectability of changes in the blood-brain barrier permeability to water using optimised multi-TE pseudo-continuous arterial spin labelling

The blood-brain barrier integrity can be reflected by the pre-exchange lifetime of water molecules, Tex, which can be measured using multi-TE multi-delay ASL. Nevertheless, the low SNR of ASL limits the detectability of subtle Tex changes within a feasible scan time for clinical applications. In this study, optimised protocols were evaluated for the theoretical detectability of 10% changes in haemodynamic parameters. Simulation shows that while changes in CBF and arterial transit time (ATT) could be detected on individual level in a five-minute scan, the same detectability of Tex would require a minimum of 6 subjects within ten minutes of scanning.