Frequency-selective inversion nulling ultra-short echo time (FINUTE) MRI for direct detection of lipids of the myelin bilayer

Motivation: Recent studies have shown the effects of lipid dyshomeostasis and demyelination in the pathology of neurodegenerative diseases, especially early-onset Alzheimer’s disease. Consequently, imaging methods to monitor these changes are necessary. Goal(s): This study uses a novel sequence, termed FINUTE, to image short T2 lipids primarily associated with the myelin bilayer. Approach: Simulations and experiments on ex-vivo spinal cord specimens are performed for validation of methodology and applied in-vivo to assess changes in myelination in a mouse model of AD. Results: Results demonstrate FINUTE’s sensitivity to myelin lipids, with statistically significant white matter(corpus callosum) and visually-apparent gray matter(hippocampus) changes present in AD animals. Impact: FINUTE presents a non-invasive MR-imaging technique that is sensitive to lipids primarily in the myelin bilayer as well as in gray matter, thus providing a method for assessing myelination and lipid dyshomeostasis in neurodegenerative diseases such as AD.