Multi-Echo-Based Echo-Planar Spectroscopic Imaging Using a 3T MRI Scanner

Jon K Furuyama; Brian L Burns; Neil E Wilson; M Albert Thomas

doi:10.3390/ma4101818

Multi-Echo-Based Echo-Planar Spectroscopic Imaging Using a 3T MRI Scanner

Materials (Basel). 2011 Oct 17;4(10):1818-1834. doi: 10.3390/ma4101818.

Authors

Jon K Furuyama¹, Brian L Burns^{1

2}, Neil E Wilson¹, M Albert Thomas³

Affiliations

¹ Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA.
² Medical Imaging Informatics (MII) Lab, University of California, Los Angeles, CA 90095, USA.
³ Department of Radiological Sciences, University of California, Los Angeles, CA 90095, USA. AThomas@mednet.ucla.edu.

Abstract

The use of spin-echoes has been employed in an Echo-Planar Spectroscopic Imaging (EPSI) sequence to collect multiple phase encoded lines within a single TR in a Multi-Echo-based Echo-Planar Spectroscopic Imaging technique (MEEPSI). Despite the T₂ dependence on the amplitude of the spin-echoes, the Full Width at Half Maximum (FWHM) of the derived multi-echo Point Spread Function (PSF) is shown to decrease, indicating an improved overall spatial resolution without requiring any additional scan time. The improved spatial resolution is demonstrated in the one-dimensional (1D) spatial profiles of the N-Acetyl Aspartate (NAA) singlet along the phase encode dimension in a gray matter phantom. Although the improved spatial resolution comes at the expense of spectral resolution, it is shown in vivo that peak broadening due to T₂^* decay is more significant than the loss of resolution from using spin-echoes and therefore does not affect the ability to quantify metabolites using the LCModel fitting algorithm.

Keywords: echo-planar spectroscopic imaging; multi-echo.

Abstract

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