Combination of multidimensional navigator echoes data from multielement RF coil

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Biomedical Engineering

Background:

• Multielement RF coils in MRI have been limited to one-dimensional navigator-echo techniques.
• Multidimensional navigator echoes are crucial for extracting six-degree of freedom motion information from k-space data.
• Efficient raw data combination methods are needed for multidimensional navigator echoes.

Purpose of the Study:

• To evaluate different raw data combination approaches for multidimensional navigator echoes.
• To assess the accuracy and precision of the spherical navigator echoes (SNAV) technique with multielement RF coils.
• To demonstrate the utility of SNAV for in vivo brain imaging and motion correction.

Main Methods:

• Comparison of three raw data combination approaches: complex data summation, phase-aligned summation, and k-space magnitude profile summation.
• Utilized spherical navigator echoes (SNAV) technique.
• In vivo brain imaging experiments with an eight-channel head coil.

Main Results:

• SNAV technique with an eight-channel head coil accurately determines rotation and translation.
• Achieved subdegree accuracy for rotation (up to 10°) and submillimeter accuracy for translation (up to 20 mm).
• Demonstrated excellent agreement in a 3D brain volume realignment experiment.

Conclusions:

• The evaluated SNAV technique provides accurate and precise motion estimation for MRI.
• This method enables robust motion correction in 3D brain imaging.
• The developed data combination approaches are effective for multidimensional navigator echoes.