By carefully choosing the<unk>  time (TI), the signal from any particular tissue can be nulled. The appropriate TI depends on the tissue via the formula: : in other words, one should typically use a TI of around 70% of the T1 value. In the case of CSF suppression, one aims for T1-weighted images, which prioritize the signal of fat over that of water. Therefore, if the long TI<unk>  time) is adjusted to a zero crossing point for water (none of its signal is visible), the signal of the CSF is theoretically being "erased," from the derived image.
Fluid-attenuated inversion recovery
Hounsfield scale
Millard criteria
RICE 
Amplified magnetic resonance imaging
Susceptibility weighted imaging
N-localizer
Ranson criteria