An improved postprocessing method for more accurate R2* measurements in the presence of macroscopic B0 field variations

Macroscopic field variations result in an overestimate of R2*. One common approach to correct the bias is to utilize a three-parameter fit; however, the fitting is subject to overfitting. This study presents a new two-stage fitting of the three-parameter model by assuming that the macroscopic field variation is slowly varying in space. Using a numerical simulation and in vivo mice data, we demonstrate that the proposed method allows for a more accurate R2* measurement, and is less sensitive to noise.