Single-shot magnetic resonance spectroscopic imaging with partial parallel imaging

Stefan Posse*, Ricardo Otazo, Shang Yueh Tsai, Akio Ernesto Yoshimoto, Fa Hsuan Lin

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

30 Scopus citations


A magnetic resonance spectroscopic imaging (MRSI) pulse sequence based on proton-echo-planar-spectroscopic-imaging (PEPSI) is introduced that measures two-dimensional metabolite maps in a single excitation. Echo-planar spatial-spectral encoding was combined with interleaved phase encoding and parallel imaging using SENSE to reconstruct absorption mode spectra. The symmetrical k-space trajectory compensates phase errors due to convolution of spatial and spectral encoding. Single-shot MRSI at short TE was evaluated in phantoms and in vivo on a 3-T whole-body scanner equipped with a 12-channel array coil. Four-step interleaved phase encoding and fourfold SENSE acceleration were used to encode a 16 x 16 spatial matrix with a 390-Hz spectral width. Comparison with conventional PEPSI and PEPSI with fourfold SENSE acceleration demonstrated comparable sensitivity per unit time when taking into account g-factor-related noise increases and differences in sampling efficiency. LCModel fitting enabled quantification of inositol, choline, creatine, and N-acetyl-aspartate (NAA) in vivo with concentration values in the ranges measured with conventional PEPSI and SENSE-accelerated PEPSI. Cramer-Rao lower bounds were comparable to those obtained with conventional SENSE-accelerated PEPSI at the same voxel size and measurement time. This single-shot MRSI method is therefore suitable for applications that require high temporal resolution to monitor temporal dynamics or to reduce sensitivity to tissue movement.

Original languageEnglish
Pages (from-to)541-547
Number of pages7
JournalMagnetic Resonance in Medicine
Issue number3
StatePublished - 03 2009
Externally publishedYes


  • Magnetic resonance spectroscopic imaging
  • Parallel imaging
  • Proton-echo-planar-spectroscopic-imaging
  • Single-shot encoding
  • Spectral quantification


Dive into the research topics of 'Single-shot magnetic resonance spectroscopic imaging with partial parallel imaging'. Together they form a unique fingerprint.

Cite this