Fluid-Attenuated Inversion Recovery Magnetic Resonance Imaging to Visualize Multiple Sclerosis Lesions

Position the head of a patient with multiple sclerosis inside the radiofrequency or RF coil of an MRI machine.

Begin fluid-attenuated inversion recovery or FLAIR imaging. Select a brain slice containing lesions near CSF-rich areas.

The system generates a strong magnetic field, aligning protons in healthy and lesioned brain tissue and CSF along its direction, creating net magnetization.

Apply an inversion RF pulse to flip the magnetization of all protons, aligning them opposite to the magnetic field.

Allow an inversion recovery time, during which CSF protons reach zero magnetization, while tissue protons retain some residual magnetization. 

Protons in lesioned areas retain higher magnetization than normal tissue due to increased water content.

Apply a second RF pulse to excite the protons with residual magnetization, generating detectable signals.

CSF, having zero magnetization, produces no signal and appears dark.

Lesioned areas, with higher residual magnetization, emit stronger signals and appear brighter than the surrounding tissue.