Snapshot CEST++: Advancing rapid whole-brain APTw-CEST MRI at 3 T

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering
• Radiology

Background:

• Amide proton transfer-weighted (APTw) chemical exchange saturation transfer (CEST) MRI typically requires long acquisition times, limiting its clinical applicability.
• Recent community consensus established optimal preparation module parameters for clinical APTw CEST at 3 Tesla.
• Existing methods pose challenges for large-scale clinical studies due to lengthy scan durations.

Purpose of the Study:

• To develop and validate a fast, whole-brain APTw CEST MRI sequence adhering to the established 3T preparation module consensus.
• To significantly reduce acquisition time for high-resolution APTw CEST imaging.
• To enable clinical research applications, particularly for brain tumor studies.

Main Methods:

• Implemented a fast snapshot CEST approach optimized for APTw imaging parameters (flip angle, voxel size, frequency offset sampling).
• Integrated undersampled gradient-recalled echo (GRE) acquisition with compressed sensing reconstruction.
• Utilized a preparation module with 2s pulsed RF irradiation, 90% duty-cycle, and 2 μT B_1,rms.

Main Results:

• Achieved 2 mm isotropic whole-brain APTw CEST imaging at 3T in under 2 minutes.
• Demonstrated a substantial reduction in acquisition time compared to conventional methods (~5 min).
• Validated the feasibility of the fast snapshot APTw CEST technique for clinical research.

Conclusions:

• A fast snapshot APTw CEST MRI sequence has been successfully developed, meeting clinical research needs for speed and resolution.
• This accelerated imaging method facilitates larger clinical studies, especially for brain tumor characterization.
• The optimized sequence provides a valuable tool for advancing clinical applications of APTw CEST MRI.