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

作者：Verma Gaurav; Chawla Sanjeev; Nagarajan Rajakumar; Iqbal Zohaib; Thomas M Albert^*; Poptani Harish

来源：Journal of Magnetic Resonance, 2017, 277: 104-112.

DOI：10.1016/j.jmr.2017.02.012

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

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.

• 出版日期2017-4