Simultaneous mapping of $T_1$, $T_2$, $B_1$, $B_0$, and $M_0$ using multiple phase-cycled bSSFP with signal profile fitting approach

Abstract

As contrast based images were influenced by acquisition methods and system condition, it might be inappropriate for inter-subject comparison, and longitudinal studies. Thus, for the purpose of improving the accuracy of clinical evaluations, quantitative MRI (qMRI) have been suggested to measure intrinsic tissue properties such as $T_1$ and $T_2$ relaxation times. Several conventional methods have been developed so far, however, these methods require a long scan time depending on scan parameters or pulse sequences. Also, a couple of imaging sequences are needed to acquire the multi-parameter maps. Hence, the simultaneous quantification methods are necessary to enhance the time-efficiency of the multi-parameter mapping. In this study, we proposed the simultaneous mapping of $T_1$, $T_2$, $B_1$, $B_0$, and $M_0$ (relative proton density) by adopting multiple phase-cycled balanced steady-state free precession (bSSFP) and a signal profile fitting algorithm based on the bSSFP signal formula. The estimated parameter maps from the proposed method were compared with those from the conventional methods through histogram and correlation analysis. The multi-parametric data sets could be effectively acquired with multiple phase-cycled bSSFP within a short time (~10min.). The proposed method provided parameter maps comparable to those from the conventional techniques, demonstrated in phantom and in-vivo experiments. The proposed method can be beneficial to many quantitative clinical applications.