Repeatability of Myelin and Myelin Water Quantification Using Short-TR Adiabatic Inversion-Recovery (STAIR) Sequences

Motivation: Myelin proton fraction (MPF) and myelin water fraction (MWF) measured with short-TR adiabatic inversion-recovery (STAIR) sequences are potential biomarkers of neurodegenerative diseases, but their repeatabilities are unknown. Goal(s): We aim to evaluate the repeatability of MPF and MWF measured with the STAIR ultrashort echo time (STAIR-UTE) and STAIR short echo time (STAIR-STE) sequences, respectively. Approach: Ten volunteers were scanned three times on different days using the same protocol, including 3D STAIR-UTE for myelin mapping and STAIR-STE for myelin water mapping on the same 3T clinical scanner. Results: Strong repeatability and agreement were demonstrated between repeated MPF and MWF measurements on each subject's scans. Impact: Strong repeatability was demonstrated for two myelin imaging biomarkers, MPF and MWF, highlighting the utility of STAIR sequences for reliable myelin mapping and potential applications in neuroinflammatory and neurodegenerative diseases.