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Artifact suppression in readout-segmented consistent K-t space EPSI (RS-COKE) for fast 1 H spectroscopic imaging at 7
Amir Seginer1, Graeme A Keith2, David A Porter2
1Siemens Healthcare Ltd, Rosh Ha'ayin, Israel.
Magnetic Resonance in Medicine
|August 17, 2022
Summary
This study enhances fast proton Magnetic Resonance Spectroscopic Imaging (MRSI) at 7 Tesla using Readout-Segmented Consistent K-t space Epsi (RS-COKE). Corrections reduced artifacts, enabling high-quality metabolic imaging for clinical research.
Area of Science:
- Magnetic Resonance Imaging
- Spectroscopic Imaging
- Neuroscience
Background:
- Proton (1 H) MRSI is crucial for clinical metabolic and spatial diagnostics.
- Higher field strengths like 7 Tesla improve Signal-to-Noise Ratio (SNR) but require wider spectral widths.
- Standard echo planar spectroscopic imaging (Epsi) struggles with the spectral width needed at 7T.
Purpose of the Study:
- To analyze and reduce artifacts in Readout-Segmented Consistent K-t space Epsi (RS-COKE) at 7 Tesla.
- To overcome spectral width limitations of standard Epsi for human brain metabolite analysis at 7T.
- To improve the quality of fast 1 H MRSI at 7T.
Main Methods:
- Implemented frequency-dependent phase corrections and k-space trajectory corrections using reference scans.
- Applied smoothing at segment transitions to mitigate readout segment mismatches.
- Evaluated performance on a head phantom and healthy subjects with varying resolutions and scan durations.
Main Results:
- Substantially reduced artifacts from readout-segmented acquisition in both phantom and human scans.
- Achieved high-quality spectroscopic imaging at 7 Tesla.
- LCModel fitting showed relative Cramer-Rao lower bounds within 6% for key metabolites (NAA, Cr, Cho) in most voxels.
Conclusions:
- RS-COKE, with implemented corrections, successfully enables fast 1 H MRSI at 7 Tesla.
- The method overcomes the spectral width limitations of standard Epsi at high field strengths.
- This advancement supports improved metabolic and spatial information for clinical investigations.
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