Methods and systems for performing T1 mapping. T1 samples are obtained from an acquisition including one or more inversion groupings. The acquisition may be designed to result in incomplete tissue magnetization recovery between inversion groupings. The acquisition may be designed for the use of non-uniform, non-180° preparatory pulses. The method may also include the combined use of data from different inversion groupings. A model is used in which fit parameters are variable dependent on the inversion grouping.