Increased flexibility in GRASE imaging by k space-banded phase encoding.


Journal Article

GRASE (GRadient and spin Echo) is an echo train imaging technique that combines gradient and RF refocusing. Although overall signal decay is with T2 and field inhomogeneity phase errors do not accumulate, the small residual phase errors are periodic with echo number. The echo order described previously eliminates the phase error periodicity in k space but instead creates periodicity in the T2 modulation function that can also cause artifacts. In addition, with this order, the effective TE must be half the echo train time, and asymmetric Fourier sampling is difficult to implement. A new method is described that greatly reduces artifacts due to T2 decay, permits greater control of T2 contrast, and lends itself to asymmetric Fourier sampling. Different time segments of the echo train are encoded with different bands of spatial frequency in k space (hence "k banding"). Both computer simulations and experimental results demonstrate improvements in GRASE images acquired by this method.

Full Text

Cited Authors

  • Feinberg, DA; Johnson, G; Kiefer, B

Published Date

  • August 1995

Published In

Volume / Issue

  • 34 / 2

Start / End Page

  • 149 - 155

PubMed ID

  • 7476072

Pubmed Central ID

  • 7476072

Electronic International Standard Serial Number (EISSN)

  • 1522-2594

International Standard Serial Number (ISSN)

  • 0740-3194

Digital Object Identifier (DOI)

  • 10.1002/mrm.1910340204


  • eng