MR Fingerprinting-based myelin water fraction: stability, spatial consistency and sensitivity to alterations in pediatric leukodystrophies

Motivation: Multicomponent Magnetic Resonance Fingerprinting (MRF) provides Myelin Water Fraction (MWF) maps in clinically-compatible scan time. However, it still requires validation and assessment of sensitivity and robustness. Goal(s): We aimed to assess MWF stability to model parameters variations, its spatial consistency in healthy children, and sensitivity to alterations in leukodystrophies. Approach: Two-pool relaxation times and exchange were varied in a 10% range. MWF profiles were computed in main WM tracts. MWF sensitivity to alterations was compared to FA, R1, and R2. Results: Model parameters changes led to minimal MWF variations. MWF revealed consistent spatial patterns in controls and showed the highest sensitivity to pathology. Impact: MRF provides robust and sensitive measurements of MWF. As it also allows the simultaneous acquisition of high-resolution R1 and R2 maps in a short scan time, it may represent a clinically-applicable metric to assess and monitor WM disorders.