A method for measuring a transverse magnetization relaxation rate that is corrected for macroscopic magnetic field inhomogeneities in a subject with a magnetic resonance imaging system, the steps of the method comprising: a) acquiring image data for a plurality of voxels with the MRI system by sampling a plurality of different echo signals occurring at a respective plurality of different echo times; b) forming a plurality of initial signal models by forming for each of the plurality of different echo signals for the plurality of voxels, an initial signal model that accounts for relative signal components for each of a plurality of different chemical species, magnetic field inhomogeneities, and transverse relaxation rate as affected by the magnetic field inhomogeneities; c) estimating magnetic field inhomogeneity values associated with the MRI system by fitting the image data acquired in step a) to the initial signal models formed in step b); d) forming a plurality of revised signal models by forming for each of the plurality of different echo signals for the plurality of voxels using the magnetic field inhomogeneity values estimated in step c), a revised signal model that accounts for relative signal components for each of a plurality of different chemical species, magnetic field inhomogeneities, transverse relaxation rate as affected by the magnetic field inhomogeneities, and for signal decay resulting from macroscopic variations in a main magnetic field of the MRI system, the macroscopic variations in the main magnetic field of the MRI system being different from the magnetic field inhomogeneity values estimated in step c); and e) estimating the transverse relaxation rate for at least one of the plurality of different chemical species by fitting the image data acquired in step a) to the revised signal models formed in step d); and wherein forming the revised signal models in step d) includes a multiplicative factor for an echo time t n accounting for the macroscopic variations in the main magnetic field of the MRI system, h ( t n), for each of the plurality of voxels as h t n = ∫ SRF r e i 2 ⁢ π g B ⋅ r d ⁢ r; wherein SRF(r) is a spatial response function that approximates signal decay associated with the macroscopic field variations in the main magnetic field of the MRI system and reflects the profile of the voxel as a function of spatial position and is approximated based on how the image data is acquired in step a), and g B is a linear variation in the main magnetic field of the MRI system over said voxel. a) acquiring image data for a plurality of voxels with the MRI system by sampling a plurality of different echo signals occurring at a respective plurality of different echo times; b) forming a plurality of initial signal models by forming for each of the plurality of different echo signals for the plurality of voxels, an initial signal model that accounts for relative signal components for each of a plurality of different chemical species, magnetic field inhomogeneities, and transverse relaxation rate as affected by the magnetic field inhomogeneities; c) estimating magnetic field inhomogeneity values associated with the MRI system by fitting the image data acquired in step a) to the initial signal models formed in step b); d) forming a plurality of revised signal models by forming for each of the plurality of different echo signals for the plurality of voxels using the magnetic field inhomogeneity values estimated in step c), a revised signal model that accounts for relative signal components for each of a plurality of different chemical species, magnetic field inhomogeneities, transverse relaxation rate as affected by the magnetic field inhomogeneities, and for signal decay resulting from macroscopic variations in a main magnetic field of the MRI system, the macroscopic variations in the main magnetic field of the MRI system being different from the magnetic field inhomogeneity values estimated in step c); and e) estimating the transverse relaxation rate for at least one of the plurality of different chemical species by fitting the image data acquired in step a) to the revised signal models formed in step d); and