FLAIR sequence
Pronunciation: FLAIR
Fluid-attenuated inversion recovery MRI sequence that suppresses cerebrospinal fluid signal while maintaining T2-weighted tissue contrast, enhancing periventricular lesion detection.
Full Definition
Fluid-attenuated inversion recovery (FLAIR) is a specialized MRI pulse sequence that combines inversion recovery with long echo times to selectively suppress cerebrospinal fluid signal while preserving T2-weighted contrast in brain parenchyma. The technique uses an inversion time precisely chosen to null CSF signal, making periventricular and cortical lesions more conspicuous by eliminating the bright CSF signal that can obscure pathology. FLAIR is particularly valuable for detecting multiple sclerosis plaques, cortical infarcts, subarachnoid hemorrhage, and meningeal enhancement. The sequence has become a standard component of brain MRI protocols due to its superior sensitivity for detecting subtle white matter abnormalities compared to conventional T2-weighted imaging.
Usage
Usage note: FLAIR is the preferred term in clinical practice; spell out 'fluid-attenuated inversion recovery' only in formal documentation.
In Context
- "Multiple periventricular hyperintense lesions were clearly visible on the FLAIR sequence but subtle on T2-weighted images." — Multiple sclerosis evaluation
- "The FLAIR sequence demonstrated hyperintense signal in the cortical sulci, consistent with subarachnoid hemorrhage." — Emergency neuroimaging report