Selective imaging of myelin based on phase transition using a 3D adiabatic inversion recovery prepared ultrashort echo time (3D IR-UTE) sequence

Motivation: There is a need for selective myelin imaging with minimal contamination from long-T2 water components. Goal(s): To develop a new contrast mechanism for direct visualization of myelin using a three-dimensional adiabatic inversion recovery prepared ultrashort echo time (3D IR-UTE) sequence. Approach: We employed the long-T2 signal phase transition in 3D dual-echo IR-UTE imaging to find the optimal inversion time (TI) necessary to null water signals for selective myelin imaging in a clinical 3T scanner. Results: Myelin signal could be selectively detected by 3D IR-UTE sequence based on long-T2 phase transition and optimal TI for both ex vivo and in vivo brains. Impact: The 3D IR-UTE sequence allows direct imaging of myelin, which is important for accurate diagnosis and assessment of multiple sclerosis (MS), Alzheimer’s disease (AD), and other neurological diseases.