Mapping of myelin water content in white matter may provide important information for early diagnosis of multiple sclerosis and the detection of white matter abnormality in other diseases. It is disclosed here that free induction decay (FID) of each voxel at multiple slice locations is acquired in the brain using an echo-planar spectroscopic imaging (EPSI) pulse sequence. The multi-slice EPSI acquisition is designed to have a short first echo time (˜2 ms) and echo-spacing (˜1 ms) in order to acquire multiple sampling points during the fast decay of the myelin water signal. Multi-compartment analysis is then applied to the FID in each pixel using a 3-pool model of white matter to obtain quantitative maps of the myelin water fraction. Using this technique, the MR data for whole brain mapping of the myelin water can be acquired in less than 10 minutes, making this technique feasible for routine clinical applications.