Real-time motion and B0 corrected single voxel spectroscopy using volumetric navigators

Area of Science:

• Magnetic Resonance Imaging
• Neuroimaging
• Spectroscopy

Background:

• Head pose variations and challenging brain regions can compromise magnetic resonance spectroscopy (MRS) quality.
• Maintaining B0 homogeneity is critical for accurate spectral data acquisition.
• Real-time optimization of volume of interest (VOI), frequency, and shimming is often required.

Purpose of the Study:

• To investigate the impact of head pose changes on B0 homogeneity in MRS.
• To develop and evaluate a real-time volume navigator for automated MRS optimization.
• To assess the system's performance in maintaining spectral linewidth with pose variations.

Main Methods:

• Quantified first-order shim changes (1 µT/m per 1° rotation) due to pose variations in a (2 cm)³ volume.
• Constructed an echo planar imaging (EPI) volume navigator for real-time VOI positioning, frequency, and first-order shim adjustment.
• Tested the EPI volume navigator in six healthy volunteers, comparing its performance to manual shimming.

Main Results:

• The EPI volume navigator achieved a mean linewidth of 4.4 Hz, comparable to manual shimming (4.9 Hz).
• The system maintained a linewidth of 4.9 Hz despite pose changes, significantly better than the uncorrected 7.5 Hz.
• Demonstrated the feasibility of real-time, automated adjustments for improved MRS data quality.

Conclusions:

• Real-time volume navigator technology effectively compensates for head pose changes in MRS.
• This automated approach ensures consistent spectral linewidth and improves data reliability in challenging conditions.
• The developed EPI volume navigator is a promising tool for robust brain spectroscopy.