Spectral phase-corrected GRAPPA reconstruction of three-dimensional echo-planar spectroscopic imaging (3D-EPSI)

Magn Reson Med. 2007 May;57(5):815-20. doi: 10.1002/mrm.21217.

Abstract

MR spectroscopic (MRS) images from a large volume of brain can be obtained using a 3D echo-planar spectroscopic imaging (3D-EPSI) sequence. However, routine applications of 3D-EPSI are still limited by a long scan time. In this communication, a new approach termed "spectral phase-corrected generalized autocalibrating partially parallel acquisitions" (SPC-GRAPPA) is introduced for the reconstruction of 3D-EPSI data to accelerate data acquisition while preserving the accuracy of quantitation of brain metabolites. In SPC-GRAPPA, voxel-by-voxel spectral phase alignment between metabolite 3D-EPSI from individual coil elements is performed in the frequency domain, utilizing the whole spectrum from interleaved water reference 3D-EPSI for robust estimation of the zero-order phase correction. The performance of SPC-GRAPPA was compared with that of fully encoded 3D-EPSI and conventional GRAPPA. Analysis of whole-brain 3D-EPSI data reconstructed by SPC-GRAPPA demonstrates that SPC-GRAPPA with an acceleration factor of 1.5 yields results very similar to those obtained by fully encoded 3D-EPSI, and is more accurate than conventional GRAPPA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aspartic Acid / analogs & derivatives
  • Aspartic Acid / metabolism
  • Brain / metabolism*
  • Choline / metabolism
  • Creatine / metabolism
  • Echo-Planar Imaging / methods*
  • Humans
  • Image Processing, Computer-Assisted / methods*
  • Imaging, Three-Dimensional*
  • Magnetic Resonance Spectroscopy / methods*
  • Middle Aged

Substances

  • Aspartic Acid
  • N-acetylaspartate
  • Creatine
  • Choline