Removal of local field gradient artifacts in T2*-weighted images at high fields by gradient-echo slice excitation profile imaging

Qing Yang, Gerald D. Williams, Roger J. Demeure, Timothy Mosher, Michael B. Smith

Research output: Contribution to journalArticlepeer-review

110 Scopus citations


Development of high magnetic field MRI techniques is hampered by the significant artifacts produced by B(o) field inhomogeneities in the excited slices. A technique, gradient-echo slice excitation profile imaging (GESEPI), is presented for recovering the signal lost caused by intravoxel phase dispersion in T2*-weighted images. This technique superimposes an incremental gradient offset on the slice refocusing gradient to sample k- space over the full range of spatial frequencies of the excitation profile. A third Fourier transform of the initial two-dimensional image set generates an image set in which the artifacts produced by the low-order B(o) inhomogeneity field gradients in the sample are separated and removed from the high-order microscopic field gradients responsible for T2* contrast. Application to high field brain imaging, at 3.0 T for human and at 9.4 T for immature rat imaging demonstrates the significant improvement in quality of the T2*- weighted contrast images.

Original languageEnglish (US)
Pages (from-to)402-409
Number of pages8
JournalMagnetic Resonance in Medicine
Issue number3
StatePublished - Mar 1998

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging


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