Fast Three-Point Approach for Volumetric T1 Mapping

Introduction: Volumetric mapping of the longitudinal relaxation time may be accomplished using multiple spoiled gradient-echo measures at different flip angles and / or TRs. While rapid and accurate T1 mapping has been demonstrated with two-point approaches using a single pair of flip angles, the use of such methods is limited at higher field strengths due to increased B1 inhomogeneity [1]. A three-point approach using data acquired at two different TRs and flip angles can compensate for inaccuracies in the transmitted flip angle, and has been shown to produce accurate whole-brain T1 maps at 1.5 T with an acquisition time of 29 minutes [2]. This relatively long acquisition time is a result of long TRs used to produce high SNR images needed for accurate T1 mapping. In this work, we explore the application of such a three-point approach towards rapid T1 mapping at 3 T. In addition to shorter TRs made possible by increased SNR at 3T, we aim to further reduce TR while maintaining strong T1 accuracy over a range of interest. While short TRs affect the ability to accurately measure long T1s, many biological tissues have reported T1 values between 1000ms-1200ms at 3T, with postcontrast T1 shortening on the order of hundreds of milliseconds [3, 4]. Here we investigate T1 mapping at 3T using this fast three-point (FTP) approach focused on a range of 300ms-1200ms and present first results in a phantom as well as whole-brain preand post-contrast T1 maps from a volunteer.