Table 1.

Advantages of disadvantages of different ASL methods

ASL Types	Advantages	Disadvantages
PASL	Higher tagging efficiency Lower SAR Improved transit time effects.	Lower SNR Increased transit delay
CASL	Higher SNR than PASL Shorter transit delay	Lower tagging efficiency Continuous RF transmit hardware required Higher SAR Magnetization Transfer effects
pCASL	Higher SNR than PASL Higher tagging efficiency than CASL Improved transit time effects.	Higher SAR Limited clinical availability.
VS-ASL	Ability to measure low	Lower SNR