Inversion recovery is a magnetic resonance imaging sequence that provides high contrast between tissue and lesion.
[1] Fluid-attenuated inversion recovery (FLAIR)[2] is an inversion-recovery pulse sequence used to nullify the signal from fluids.
For example, it can be used in brain imaging to suppress cerebrospinal fluid so as to bring out periventricular hyperintense lesions, such as multiple sclerosis plaques.
Thus, this sequence is useful in detecting small changes on the brain cortex such as focal cortical dysplasia and hippocampal sclerosis in those with epilepsy.
[8] Erwin Hahn first used inversion recovery technique to determine the value of T1 (the time taken for longitudinal magnetisation to recover 63% of its maximum value) for water in 1949, 3 years after the nuclear magnetic resonance was discovered.