Optimisation and Validation of Fetal Brain T1 Mapping under Breath-Hold at 1.5T: Utilising Look-Locker and MOLLI Methods

Motivation: Characterising T1 values in the fetal brain can aid in the optimisation of T1-weighted sequences, but literature at 1.5T is limited and most mapping methods are long and motion intolerant. Goal(s): Optimise T1 mapping methods for use in utero, limiting acquisition time to a maternal breath-hold. Approach: Compare various fast mapping methods and validate accuracy against inversion recovery spin-echo mapping in a test object. Results: A Look-Locker approach sampling 12 TIs every 800ms was the most accurate with relatively low standard deviation over the range of T1s expected in the fetal brain, while restricting acquisition time to one breath-hold per slice. Impact: Performing T1 mapping on a cohort of fetal participants will allow a more comprehensive dataset to be collected, enabling T1 contrast to be better optimised in fetal imaging and expanding on the T1 characterisation available in the literature.