Image Encoding With Blipped Gradients in an Echo Train.

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Medical Physics

Background:

• Traditional MRI systems face limitations in Size, Weight, and Power (SWaP), hindering their deployment in space-constrained or mobile applications.
• Previous MRI designs, such as TRansmit Array Spatial Encoding (TRASE), encountered challenges with achieving spatially uniform B1 phase for RF encoding coils.
• The need for compact and efficient MRI technology is critical for advancing medical diagnostics and research.

Purpose of the Study:

• To design and construct a novel MRI scanner capable of encoding k-space points within spin echoes.
• To utilize blipped B0 gradient pulses applied prior to 180-degree pulses for k-space encoding.
• To overcome limitations of previous MRI encoding techniques and enable compact system development.

Main Methods:

• Modified an existing MRI design, replacing the RF encoding coil with a low-power B0 gradient coil.
• Implemented a pulse sequence with 180-degree RF pulses and interleaved B0 gradient pulses.
• Achieved k-space encoding in one transverse direction using spin echoes and in the perpendicular direction via frequency encoding with a built-in transverse B0 gradient.
• Validated the approach using mineral oil phantoms for proof-of-concept.

Main Results:

• Demonstrated a proof-of-concept for the blipped-gradient MRI design through phantom imaging.
• Successfully encoded k-space points using the novel blipped-gradient pulse sequence.
• Verified the feasibility of the modified MRI scanner architecture.

Conclusions:

• The blipped-gradient MRI approach provides a viable method for k-space encoding.
• Further engineering refinements can address imperfections and optimize the system.
• This technology holds potential for meeting extreme SWaP requirements for spaceworthy MRI applications.