T2FLAIR

T2FLAIR, short for T2-weighted Fluid-Attenuated Inversion Recovery, is an MRI sequence that combines inversion recovery with T2-weighted imaging to suppress the signal from cerebrospinal fluid (CSF). By nulling CSF, T2FLAIR enhances the visibility of pathology in the brain’s periventricular and cortical-subcortical regions, where lesions may otherwise be obscured by bright CSF signal on standard T2-weighted images.

The technique relies on an inversion pulse and a carefully chosen inversion time to effectively silence CSF signal, producing a dark CSF background while preserving or enhancing T2-related tissue contrast. Typical inversion times to null CSF are in the range of about 2000–2500 milliseconds at 1.5 tesla, with longer values at higher field strengths. The sequence is commonly acquired as part of a comprehensive brain MRI protocol and is often used after routine T1- and T2-weighted imaging.

Clinical indications for T2FLAIR include detection and characterization of demyelinating diseases (notably multiple sclerosis plaques), assessment of edema and gliosis, ischemic and infectious pathologies, and evaluation of meningeal or cortical/subcortical abnormalities. Its ability to suppress CSF makes it particularly useful for identifying subtle periventricular lesions and cortical-subcortical abnormalities that may be less conspicuous on standard T2 imaging.

Limitations include incomplete CSF suppression in certain regions (such as near the tentorium or skull base), greater sensitivity to magnetic field inhomogeneities, and longer scan times compared with some other sequences. Like all MRI sequences, T2FLAIR is contraindicated in patients with incompatible implants or devices and requires appropriate patient screening and safety measures.