The MR simulator (MRISIM) [14] predicts image contrast by computing NMR signal intensities from a discrete-event simulation of pulse sequences based on the Bloch equations. In order to simulate realistic MRI images of the human brain using MRISIM, the phantom was used to map tissue intensities into images. The simulator accounts for the effects of various image acquisition parameters by incorporating partial volume averaging, noise and intensity non-uniformity (see Fig. 4a).