High-Resolution 3D Spin-Echo MRSI Using Interleaved Water Navigators, Sparse Sampling and Subspace-Based Processing.

Area of Science:

• Magnetic Resonance Imaging
• Spectroscopic Imaging
• Medical Physics

Background:

• Magnetic Resonance Spectroscopic Imaging (MRSI) provides valuable molecular information but is often limited by speed and resolution.
• Accelerating MRSI acquisition is crucial for clinical applications, enabling volumetric coverage and detailed analysis.

Purpose of the Study:

• To develop an accelerated, high-resolution MRSI method using spin-echo excitations.
• To improve the speed and spatial resolution of volumetric MRSI for clinical relevance.

Main Methods:

• A novel data acquisition strategy integrating adiabatic refocusing, lipid suppression elimination, rapid spatiospectral encoding with sparse (k,t)-space sampling, and interleaved water navigators.
• A data processing strategy combining parallel imaging reconstruction and subspace-based processing for high-SNR spatiospectral reconstruction from sparsely sampled data.

Main Results:

• Achieved volumetric MRSI with a spatial resolution of approximately 3 × 3.4 × 4 mm³.
• Acquisition time was reduced to less than 10 minutes, eliminating the need for separate field mapping and coil sensitivity scans.
• High-SNR spatiospectral reconstruction was obtained from sparsely sampled, noisy data.

Conclusions:

• The proposed method significantly enhances the combination of volume coverage, spatial resolution, and speed in MRSI.
• This accelerated MRSI technique holds potential for providing molecular-level insights into brain function and disease.
• It may offer new biomarkers for disease diagnosis and treatment monitoring.