Lin Y, Lin L, Wei Z, Zhong J, Chen Z. Localized one-dimensional single voxel magnetic resonance spectroscopy without J coupling modulations.
Magn Reson Med 2015;
76:1661-1667. [PMID:
26667321 DOI:
10.1002/mrm.26066]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/26/2015] [Accepted: 10/31/2015] [Indexed: 11/12/2022]
Abstract
PURPOSE
To acquire single voxel localized one-dimensional 1 H magnetic resonance spectroscopy (MRS) without J coupling modulations, free from amplitude and phase distortions.
METHODS
A pulse sequence, named PRESSIR, is developed for volume localized MRS without J modulations at arbitrary echo time (TE). The J coupling evolution is suppressed by the J-refocused module that uses a 90° pulse at the midpoint of a double spin echo.
RESULTS
The localization performance of the PRESSIR sequence was tested with a two-compartment phantom. The proposed sequence shows similar voxel localization accuracy as PRESS. Both PRESSIR and PRESS sequences were performed on MRS brain phantom and pig brain tissue. PRESS spectra suffer from amplitude and phase distortions due to J modulations, especially under moderate and long TEs, while PRESSIR spectra are almost free from distortions.
CONCLUSION
The PRESSIR sequence proposed herein enables the acquisition of single voxel in-phase MRS within a single scan. It allows an enhanced signal intensity of J coupling metabolites and reducing undesired broad resonances with short T2s while suppressing J modulations. Moreover, it provides an approach for direct measurement of nonoverlapping J coupling peaks and of transverse relaxation times T2s. Magn Reson Med 76:1661-1667, 2016. © 2015 International Society for Magnetic Resonance in Medicine.
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