Phosphorus magnetic resonance spectroscopic imaging using flyback echo planar readout trajectories

Area of Science:

• Magnetic Resonance Imaging
• Spectroscopy
• Biophysics

Background:

• Phosphorus magnetic resonance spectroscopic imaging (31P-MRSI) is crucial for metabolic studies.
• Conventional MRSI sequences can be time-consuming, limiting clinical applications.
• Faster acquisition methods are needed to improve the utility of 31P-MRSI.

Purpose of the Study:

• To introduce and evaluate a novel, rapid 31P-MRSI sequence.
• The sequence utilizes echo planar spectroscopic imaging (EPSI) with flyback readout gradient trajectories.
• To assess the efficiency and reliability of this new sequence.

Main Methods:

• Developed and implemented a fast EPSI sequence with flyback readout on a 3 Tesla MRI system.
• Acquired 31P spectra at 2x2 cm2 and 3x3 cm2 resolutions.
• Tested the sequence on a phosphate phantom, healthy human calf muscles, and brains.

Main Results:

• The flyback EPSI sequence demonstrated 10x and 7x reductions in acquisition time compared to conventional MRSI.
• Achieved high signal-to-noise ratio (SNR) per unit of time efficiency.
• No significant differences were observed in metabolite quantification between the methods.

Conclusions:

• EPSI with flyback readout is a viable and efficient alternative for 31P-MRSI.
• This method significantly shortens acquisition times while maintaining data quality.
• The sequence offers a reliable approach for metabolic imaging.