Self-gated respiratory-resolved 4D T1 mapping of the carotid vessel wall with B1+ correction

Motivation: Neck T1 mapping can be used to quantify carotid vessel wall and plaque components but can be biased by B1+ inhomogeneities and motion (e.g. respiration, swallowing, pulsation). Goal(s): To combine a double-flip-angle (2FA) free-running technique for B1+ correction with self-gated respiratory-resolved reconstruction to improve T1 map accuracy and precision. Approach: Inversion pulses were included in a free-running gradient-echo sequence in which the flip angle was alternated for T1 mapping. Self-gated respiratory signals were extracted using singular spectrum analysis and second-order blind identification. Results: The 2FA technique prevented T1 overestimation in the vessel wall, and end-expiration maps showed improved intersubject variability over static maps. Impact: End-expiratory T1 mapping generated with a respiratory-resolved free-running framework using inversion pulses and an interleaved double flip angle technique reduces T1 overestimation in the carotid vessel wall and offers improved intersubject variability compared to single flip angle and MOLLI maps.