Simulation of echo planar imaging in MRI: Application to assessment of field inhomogeneity and chemical shift

In this paper we simulated echo planar imaging (EPI) pulse sequence in 3D SIMRI simulator based on solution of the Bloch equation. The novelty of our work is the modification of simulator to simulate EPI which has a rectilinear trajectory in k-space. In this flexible simulation we assessed the effect of imaging speed (via number of excitations) on the image quality. We also evaluated the effect of static field inhomogeneity and chemical shift for various types of magnetic resonance (MR) pulse sequences, such as spin-echo (SE), gradient-echo (GE) and True fast imaging with steady state precession (True-FISP) and compared them with that of EPI. The results confirm that with increasing number of shots (in multi-shot EPI) increases the image quality and suppresses the effects of disturbances.