Three-Dimensional Tailored RF Pulses for the Reduction of Susceptibility Artifacts in T2* Weighted Functional MRI

摘要

A three-dimensional tailored RF pulse method for reducing intravoxel dephasing artifacts in T2* weighted functional MRI is presented. A stack of spirals k-space trajectory is employed to excite a disk of magnetization for small tip angles. Smaller disks with a linear through-plane phase are inserted into the disk to locally refocus regions which are normally dephased due to susceptibility variations. Numerical simulations and imaging experiments which use the tailored RF pulses are presented. Limitations of the method and improvements are also discussed.