Non-uniformly weighted sampling for faster localized two-dimensional correlated spectroscopy of the brain in vivo

Gaurav Verma, Sanjeev Chawla, Rajakumar Nagarajan, Zohaib Iqbal, M. Albert Thomas, Harish Poptani

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Two-dimensional localized correlated spectroscopy (2D L-COSY) offers greater spectral dispersion than conventional one-dimensional (1D) MRS techniques, yet long acquisition times and limited post-processing support have slowed its clinical adoption. Improving acquisition efficiency and developing versatile post-processing techniques can bolster the clinical viability of 2D MRS. The purpose of this study was to implement a non-uniformly weighted sampling (NUWS) scheme for faster acquisition of 2D-MRS. A NUWS 2D L-COSY sequence was developed for 7T whole-body MRI. A phantom containing metabolites commonly observed in the brain at physiological concentrations was scanned ten times with both the NUWS scheme of 12:48 duration and a 17:04 constant eight-average sequence using a 32-channel head coil. 2D L-COSY spectra were also acquired from the occipital lobe of four healthy volunteers using both the proposed NUWS and the conventional uniformly-averaged L-COSY sequence. The NUWS 2D L-COSY sequence facilitated 25% shorter acquisition time while maintaining comparable SNR in humans (+0.3%) and phantom studies (+6.0%) compared to uniform averaging. NUWS schemes successfully demonstrated improved efficiency of L-COSY, by facilitating a reduction in scan time without affecting signal quality.

Original languageEnglish (US)
Pages (from-to)104-112
Number of pages9
JournalJournal of Magnetic Resonance
StatePublished - Apr 1 2017
Externally publishedYes


  • Coil Combination
  • Localized correlated spectroscopy (L-COSY)
  • Magnetic resonance spectroscopy (MRS)
  • NAA, Cr, Ch, GSH, GABA
  • Non-uniformly weighted sampling
  • Two-dimensional L-COSY
  • Uniformly averaged

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Nuclear and High Energy Physics
  • Condensed Matter Physics


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