Prospective motion correction with NMR markers using only native sequence elements.

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Neuroimaging

Background:

• Head motion during brain MRI significantly degrades image quality and can compromise diagnostic accuracy.
• Existing prospective motion correction (PMC) methods often require modifications to standard MRI sequences, limiting their clinical applicability.
• Accurate and real-time motion tracking is crucial for robust PMC.

Purpose of the Study:

• To develop a method for tracking active Nuclear Magnetic Resonance (NMR) markers.
• To enable prospective motion correction (PMC) in brain MRI without altering common imaging sequences.
• To achieve high-precision motion tracking compatible with standard MRI protocols.

Main Methods:

• NMR markers were localized by rapidly acquiring and jointly evaluating short signal snippets.
• Spatial encoding of markers was achieved by timing snippets to accrue signal phase during diverse gradient actuation.
• Markers were mounted on a headset for motion tracking and PMC during high-resolution T2*- and T1-weighted brain imaging sequences.

Main Results:

• Motion tracking achieved precisions of approximately 10 µm and 0.01° with temporal resolutions of 48 ms and 39 ms.
• Prospective motion correction (PMC) significantly improved image quality across both T2*- and T1-weighted sequences.
• The method demonstrated effectiveness with both instructed and unintentional head motion.

Conclusions:

• The developed approach allows for high-precision motion tracking and PMC using standard, unaltered MRI sequences.
• This method overcomes a major limitation by not requiring sequence design modifications, facilitating routine clinical use of NMR markers for motion correction.
• The findings support the integration of this technique for enhanced brain MRI quality and reliability.