Motion-corrected brain MRI at ultralow field (64 mT)

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging

Background:

• Patient motion is a significant challenge for ultralow-field (ULF) MRI, particularly in portable, point-of-care applications.
• Improving reconstructed image quality in ULF MRI is crucial for clinical viability.

Purpose of the Study:

• To investigate the feasibility of retrospective motion-correction for ULF MRI data.
• To enhance reconstructed image quality in the presence of patient motion.

Main Methods:

• Tested the alignedSENSE method, an iterative motion correction and reconstruction technique with SENSE, on ULF MRI data.
• Applied corrections for within-scan phase variations alongside motion correction.
• Evaluated corrections on in vivo brain volumetric data from five healthy volunteers using a 64 mT portable MRI scanner.

Main Results:

• Motion correction, especially when accounting for within-scan phase variations, significantly improved ULF MRI image quality.
• Jointly estimating motion and phase variations increased data consistency and improved image quality across various motion levels.
• Combined corrections outperformed conventional parallel imaging reconstruction, though extreme motion remains a challenge.

Conclusions:

• AlignedSENSE motion-correction techniques are effective for ULF MRI systems.
• These techniques enhance ULF MRI image quality without increasing scan time.
• The findings support the clinical viability of ULF MRI for point-of-care imaging.