suppression vs saturation

[aelster]

Signal from a tissue (such as fat) can be suppressed several techniques, of which saturation is only one method.

Saturation typically involves applying a radiofrequency pulse at the resonance frequency of the tissue you wish to suppress ("fat sat pulse").

However, fat can also be suppressed on a STIR sequence, for example, by inverting its magnetization and then imaging at a specific time (TI) to catch the fat when it goes through zero and has no signal. This is fat suppression without saturation. An opposed phase method such as the Dixon technique is another method of fat suppression without saturation.