suppression vs saturation

[fungfung310@gmail.com]

HI,

I am reading journals about ASL and I always encounter these two terms, "saturation" and "suppression"

For Example, pre-labelling saturation and background suppression

I would like to know the differences between this two terms.
For my understanding, If I would like to "suppress" the fat signals, I could excite those spins by 90 , then using spoiler to "saturate" those spins ( dephasing ). So technically they are the same ?

Agian, thanks for everyone