Super-resolved parallel MRI by spatiotemporal encoding.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Technology
• Biophysics

Background:

• Spatiotemporal (SPEN) MRI offers advantages for ultrafast imaging.
• Existing SPEN methods require enhancement to compete with EPI-based alternatives, particularly in parallel imaging capabilities.
• Achieving competitive acceleration factors without compromising SPEN's core strengths is crucial.

Purpose of the Study:

• To develop and validate a parallel imaging approach for ultrafast Spatiotemporal (SPEN) MRI.
• To reduce excitation and acquisition times in sub-second SPEN scans using acceleration.
• To maintain spatial resolution, SAR deposition, and multi-slice capability during accelerated SPEN acquisition.

Main Methods:

• Implementation of multi-band frequency-swept pulses for simultaneous encoding of multiple partial fields-of-view.
• Development of a novel algorithm merging Super-Resolved SPEN image reconstruction with SENSE parallel imaging.
• Validation using phantoms and human volunteers at 3 Tesla.

Main Results:

• Demonstrated reduction in excitation and acquisition times by an acceleration factor R.
• Preservation of spatial resolution, specific absorption rate (SAR), and multi-slice imaging capability.
• Significant performance gains observed in heterogeneous systems with substantial T2/T2* effects, such as near tissue/air interfaces.

Conclusions:

• The combined multi-band SPEN and parallel imaging approach effectively accelerates ultrafast MRI acquisition.
• This method provides a competitive alternative to existing ultrafast techniques by enhancing speed without compromising image quality or functionality.
• The technique shows particular promise for challenging imaging scenarios near tissue-air boundaries.