IR TrueFISP with a golden-ratio-based radial readout: fast quantification of T1, T2, and proton density.

A promising approach for the simultaneous quantification of relative proton density (M(0)), T(1), and T(2) is the inversion-recovery TrueFISP sequence, consisting of an inversion pulse followed by a series of balanced steady-state free precession acquisitions. Parameters can then be obtained from a mono-exponential fit to the series of images. However, a segmented acquisition is usually necessary, which increases the total acquisition time considerably. The goal of this study is to obtain M(0), T(1), and T(2) maps using a single-shot acquisition, with T(1) and T(2) measurements in brain that are consistent with the published literature, with a 20-fold speed improvement over the segmented approach, and at a clinically relevant spatial resolution. To this end, a single-shot inversion-recovery TrueFISP sequence was combined with a radial view-sharing technique. The parameters M(0), T(1), and T(2) were then obtained on a pixel-wise basis from a three fit parameter to the signal evolution. The accuracy of this method for quantifying these parameters is demonstrated in vivo. In addition, further corrections to the quantification necessary owing to other experimental factors, namely magnetization transfer and imperfect slice profiles, were developed. Including additional scans necessary for these corrections in the measurement protocol, the required scan time is increased from approximately 6 to 18-28 s per slice.