View Order With Arbitrary Center Echoes

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Image Reconstruction

Background:

• Multi-shot MRI sequences like RARE and MPRAGE are crucial for high-resolution imaging.
• Selecting the center echo in k-space is vital for image quality and contrast.
• Current methods can limit flexibility and introduce artifacts.

Purpose of the Study:

• To develop vendor-independent view-order constructions for arbitrary center echo selection in multi-shot MRI.
• To enable explicit control over echo and shot indices, focusing on RARE and MPRAGE sequences.
• To avoid discontinuities near the k-space center.

Main Methods:

• Developed vendor-independent view-order methods to assign echo and shot indices.
• Implemented and evaluated methods in 2D RARE, 3D RARE, and MPRAGE sequences.
• Utilized phantom and in vivo experiments, supported by an interactive dashboard.

Main Results:

• Achieved explicit selection of the center echo/shot without altering scan parameters.
• Demonstrated controllable T2 weighting in RARE and T1 weighting in MPRAGE by varying the center echo.
• Observed artifact patterns consistent with echo-index distribution properties.

Conclusions:

• Arbitrary-center view orders decouple scan parameters from center-echo selection.
• These constructions are compatible with various sampling strategies (partial Fourier, parallel imaging) and sequences.
• Arbitrary center echoes provide enhanced control over image contrast and sequence design flexibility.