Fast and motion-robust saturation transfer MRI with inherent B₀ correction using rosette trajectories and compressed...

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering

Background:

• Chemical Exchange Saturation Transfer (CEST) and Magnetization Transfer (MT) imaging are valuable MRI techniques.
• Challenges include long acquisition times, motion sensitivity, and B0 inhomogeneity, hindering clinical application.

Purpose of the Study:

• To develop and validate rosette readout trajectories with compressed sensing for fast, motion-robust CEST and MT imaging.
• To achieve inherent correction of B0 inhomogeneity during image acquisition.

Main Methods:

• A novel pulse sequence utilizing a stack of rosette trajectories with higher k-space center density was implemented.
• Dual-echo images were generated for B0 inhomogeneity estimation and correction.
• The method was evaluated on phantoms and healthy volunteers at 3T, comparing it to Cartesian acquisition.

Main Results:

• Compressed sensing reconstructed rosette images demonstrated superior contrast-to-noise ratio and faster readout compared to Cartesian acquisition.
• Accurate B0 maps were obtained with negligible bias.
• Water-saturation spectra and amide proton transfer signals were well-preserved.

Conclusions:

• Rosette trajectories enable fast, motion-robust, and B0-corrected CEST and MT imaging.
• This approach enhances image quality and subject comfort, potentially accelerating clinical adoption of CEST-MRI.