$$$R_2^*$$$ Correction for Gradient Echo with a Gaussian Excitation Pulse

Macroscopic field inhomogeneities increase the effective transverse relaxation rate R₂^*. In contrast to conventional models assuming ideal rectangular pulses, we developed an R₂^* correction model for Gaussian excitation pulses. After demonstrating the validity of the model in phantom measurements we measured 10 volunteers with 2mm and 4mm slice thickness, respectively. Uncorrected and corrected R₂^* values were assessed regionally and a significant effect of the correction was observed. An advantage of the proposed method is that it only requires two echoes, rendering it useful in clinical MRI.