Multi-contrast dual-resolution UTE for myelin fraction mapping and structural imaging

PURPOSE: To introduce and evaluate a novel multi-contrast dual-resolution 3D-UTE sequence (multi-UTE) for cerebral myelin fraction (MF) estimation in vivo and benchmark it against electron microscopy-based myelin volume fraction. THEORY AND METHODS: of the myelin bilayer. In this work, a high-resolution UTE pulse sequence with 1-1 binomial water excitation pulses was combined with interleaved multi-echo UTE acquisitions at lower resolution, enabling simultaneous acquisition of quantitative, water-excited, high-resolution T1-weighted structural images. The study included two ex vivo sheep brains, five healthy volunteers, and three patients with multiple sclerosis (MS) were measured. MF maps were calculated using multi-UTE and compared to histology. Magnetization transfer ratio using routine sequences was also calculated as a reference. RESULTS: = 0.86) across 120 samples from different brain regions. CONCLUSION: Multi-UTE showed the strongest correlations with electron microscopy (EM) histology, and the MF maps overlapped with the lesions in MS patients. Multi-UTE may provide complementary insights for myelin quantification in various inflammatory and neurodegenerative diseases.