Online motion correction for diffusion-weighted imaging using navigator echoes: Application to RARE imaging without...

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Physics
• Neuroimaging

Background:

• Diffusion-weighted imaging (DWI) is crucial for detecting brain abnormalities.
• Motion artifacts severely degrade DWI quality, hindering accurate diagnosis.
• Existing motion correction methods are often offline or insufficient for rapid imaging sequences.

Purpose of the Study:

• To implement and evaluate true online motion correction for diffusion-weighted RARE imaging.
• To assess the impact of online motion correction on image quality and artifact reduction.
• To demonstrate the feasibility of this technique in human brain imaging.

Main Methods:

• Developed a real-time motion correction system using orthogonal navigator echoes.
• Applied zeroth- and first-order phase corrections within 8 ms using B(0)-coil and gradient pulses.
• Acquired diffusion-weighted RARE images of healthy volunteer brains with EGG-triggered acquisition.
• Compared image quality with and without online motion correction.

Main Results:

• Online motion correction successfully minimized irreversible signal loss during imaging.
• Images acquired with online correction exhibited remarkably high quality.
• Images acquired without motion correction were severely degraded by motion artifacts.
• The technique was effective even with a RARE factor of 16 and b-value of 804 s/mm².

Conclusions:

• True online motion correction is feasible and highly effective for diffusion-weighted RARE imaging.
• This technique significantly enhances image quality by reducing motion-induced artifacts.
• It holds great potential for improving diagnostic accuracy in neuroimaging applications.