Quantitative myelin water assessment for multiple sclerosis using multi-inversion magnetic resonance fingerprinting

Area of Science:

• Neuroimaging
• Biomarker Discovery
• Demyelination Research

Background:

• Multiple Sclerosis (MS) is a central nervous system demyelination disease.
• Myelin water is a key biomarker for myelin integrity.
• Myelin water imaging provides crucial insights into the demyelination process in MS.

Purpose of the Study:

• To characterize myelin water fraction (MWF), gray matter (GM) cellular water, white matter (WM) cellular water, and cerebrospinal fluid (CSF) in a clinical MS cohort.
• To utilize multiple inversion recovery (mIR) magnetic resonance fingerprinting (MRF) for multi-compartment characterization.
• To assess the utility of mIR-MRF in a clinical setting for MS.

Main Methods:

• Phantom experiments with varying myelin concentrations.
• In-vivo study with 23 healthy controls and 18 MS patients using a 3T MRI scanner.
• Acquisition of MWF, WM cellular water, GM cellular water, and CSF maps using a 6-minute mIR-MRF protocol.

Main Results:

• Phantom results confirmed MWF detection across different myelin concentrations.
• Generated mIR-MRF maps (MWF, cellular water, CSF) aligned with anatomical structures.
• Significantly lower MWF in MS patients' normal-appearing white matter (NAWM) compared to healthy controls (0.25 ± 0.036 vs. 0.32 ± 0.025).
• MWF in MS white matter lesions was markedly reduced (0.034 ± 0.036) compared to NAWM.

Conclusions:

• The mIR-MRF technique enables simultaneous multi-compartment mapping (MWF, cellular water, CSF) efficiently.
• This technique provides brain coverage in a short scan time.
• MWF mapping shows potential for understanding MS-related demyelination.