FLAIR sequence
Also written as: FLAIR — fluid-attenuated inversion recovery
Fluid-attenuated inversion recovery MRI sequence that suppresses CSF signal to highlight periventricular lesions.
Full Definition
Fluid-attenuated inversion recovery (FLAIR) is a specialized magnetic resonance imaging sequence that suppresses the signal from cerebrospinal fluid while maintaining contrast between brain tissue and pathological lesions. This technique is particularly valuable in neuroimmunology for detecting inflammatory lesions adjacent to CSF spaces, such as periventricular white matter lesions in multiple sclerosis. FLAIR sequences enhance the conspicuity of lesions that might be obscured by bright CSF signal on conventional T2-weighted images. The sequence uses a specific inversion time to null the signal from free water (CSF), making it especially sensitive for detecting cortical lesions, leptomeningeal enhancement, and inflammatory changes in the brain parenchyma adjacent to ventricular surfaces.
Usage
Usage note: Capitalize FLAIR when used as an acronym; specify 'sequence' or 'imaging' for clarity.
In Context
- "FLAIR sequence demonstrated multiple hyperintense periventricular lesions consistent with demyelinating disease." — MRI report
- "The lesion was more conspicuous on FLAIR than on conventional T2-weighted images." — Radiology interpretation