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

David A. Feinberg, Gyln Johnson, Berthold Kiefer

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)149-155
Number of pages7
JournalMagnetic Resonance in Medicine
Issue number2
Publication statusPublished - Aug 1995


  • fast imaging
  • magnetic resonance imaging

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