New spatiotemporal approaches for fully refocused, multislice ultrafast 2D MRI

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Advanced imaging techniques

Background:

• Echo-planar imaging (EPI) is a key ultrafast MRI technique but suffers from T2* artifacts.
• Spatiotemporal encoding (SPEN) offers an alternative, particularly in its full-refocusing mode.
• Previous SPEN implementations were limited to single-slice acquisitions.

Purpose of the Study:

• To extend full-refocusing SPEN to multislice schemes for 3D volume scanning.
• To evaluate the performance of these novel multislice SPEN techniques.

Main Methods:

• Demonstrated multislice SPEN using inversion or stimulated echo pulses with full refocusing.
• Examined performance in Hybrid (k- and direct-space), low specific absorption rate (SAR) stimulated-echo, and direct-space SPEN approaches.

Main Results:

• Single-shot multislice SPEN sequences showed robustness, sensitivity, and resolution comparable to 2D single-slice SPEN.
• Enabled rapid sampling of the third dimension through multislicing.
• Phantom and in vivo tests confirmed the quality of the acquired 3D volumes.

Conclusions:

• Fully refocused, multislice, single-scan SPEN sequences provide significant benefits for 3D MRI.
• Validated in vivo at 3T and 7T, demonstrating high-quality volumetric imaging.
• Developed low SAR multislice SPEN variants suitable for human studies.