Simultaneous High-Resolution 3D Metabolic Imaging and Myelin/Axonal Water Fraction Mapping in Multiple Sclerosis Using SPICE

Motivation: Improved characterization of multiple sclerosis (MS) using both neurometabolite and myelin/axonal water-based biomarkers. Goal(s): To demonstrate simultaneous high-resolution whole-brain metabolic imaging and myelin/axonal/extracellular water fraction mapping in MS. Approach: MRSI scans without water suppression using SPICE (11.35-min scan; T2*: 2.0×1.0×1.0 mm³; MRSI: 2.0×3.0×3.3 mm³) were performed on 45 MS patients. A model-based method was used for myelin/axonal/extracellular water fraction mapping from the unsuppressed water signals. Results: Our method captured concurrent myelin/axonal/extracellular water fraction and neurometabolic alterations between lesion and normal tissues, as well as across patient groups. Impact: Simultaneous high-resolution whole-brain metabolic imaging and myelin/axonal water fraction mapping may provide useful biomarkers to characterize MS pathophysiology.