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Accelerated proton echo planar spectroscopic imaging (PEPSI) using GRAPPA with a 32-channel phased-array coil
Shang-Yueh Tsai1, Ricardo Otazo, Stefan Posse
1Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
Magnetic Resonance in Medicine
|April 23, 2008
Summary
Accelerated magnetic resonance spectroscopic imaging (MRSI) using a 32-channel coil array and GRAPPA significantly reduces scan times for mapping brain metabolites like NAA and tCr.
Area of Science:
- Magnetic Resonance Imaging
- Spectroscopy
- Neuroscience
Background:
- Parallel imaging techniques accelerate Magnetic Resonance Spectroscopic Imaging (MRSI) acquisition.
- Proton Echo Planar Spectroscopic Imaging (PEPSI) is a key MRSI method.
Purpose of the Study:
- To investigate accelerated 2D PEPSI at 3T using a 32-channel coil array and GRAPPA.
- To evaluate the impact of acceleration on signal-to-noise ratio (SNR) and metabolite quantification.
Main Methods:
- Utilized a 32-channel coil array for up to 5-fold acceleration of 2D PEPSI.
- Employed Generalized Autocalibrating Partial Parallel Acquisition (GRAPPA) reconstruction.
- Compared results with an 8-channel array and Sensitivity Encoding (SENSE) reconstruction.
Main Results:
- The 32-channel array improved SNR by 3.1-fold (peripheral) and 2.8-fold (central) compared to an 8-channel array.
- GRAPPA and SENSE showed comparable metabolite quantification accuracy.
- Mean Cramer-Rao lower bounds (CRLB) remained below 11% for key metabolites at 4-fold acceleration.
Conclusions:
- A 32-channel coil array combined with GRAPPA significantly shortens MRSI measurement times.
- This approach enables efficient mapping of brain metabolites with high accuracy.
- Accelerated MRSI is crucial for clinical and research applications.
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