A system and method are provided for determining B1 inhomogeneities or creating a T1 map of a subject using a magnetic resonance imaging (MRI) system that is corrected for an influence of a presence of fat and a presence of iron in the subject on T1 weighting. The method includes controlling the MRI system using a single pulse sequence to acquire, from the subject, a plurality of datasets with varied T1 weighting created by varying at least one of a repetition time (TR) and a flip angle (FA) for repetitions of the single pulse sequence. The method also includes using an MR signal model and the plurality of datasets, estimating B1 inhomogeneities or generating a T1 map of the subject that is corrected for an influence of a presence of fat and a presence of iron in the subject on T1 weighting in the plurality of datasets.