Improved quantification precision of human brain short echo-time 1H magnetic resonance spectroscopy at high magnetic field: A simulation study

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Abstract

Purpose:

The gain in quantification precision that can be expected in human brain 1H MRS at very high field remains a matter of debate. Here, we investigate this issue using Monte-Carlo simulations.

Methods:

Simulated human brain-like 1H spectra were fitted repeatedly with different noise realizations using LCModel at B0 ranging from 1.5T to 11.7T, assuming a linear increase in signal-to-noise ratio with B0 in the time domain, and assuming a linear increase in linewidth with B0 based on experimental measurements. Average quantification precision (Cramér–Rao lower bound) was then determined for each metabolite as a function of B0.

Results:

For singlets, Cramér–Rao lower bounds improved (decreased) by a factor of ˜ Symbol as B0 increased, as predicted by theory. For most J-coupled metabolites, Cramér–Rao lower bounds decreased by a factor ranging from Symbol to B0 as B0 increased, reflecting additional gains in quantification precision compared to singlets owing to simplification of spectral pattern and reduced overlap.

Conclusions:

Quantification precision of 1H magnetic resonance spectroscopy in human brain continues to improve with B0 up to 11.7T although peak signal-to-noise ratio in the frequency domain levels off above 3T. In most cases, the gain in quantification precision is higher for J-coupled metabolites than for singlets. Magn Reson Med 72:20–25, 2014. © 2013 Wiley Periodicals, Inc.

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