Real-time motion correction using gradient tones and head-mounted NMR field probes.

Area of Science:

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

Background:

• Motion artifacts are a significant challenge in MRI, leading to reduced image quality and diagnostic accuracy.
• Existing prospective motion correction techniques often require sequence modifications or are limited in their applicability.
• Accurate real-time tracking of probe position is crucial for advanced MRI applications.

Purpose of the Study:

• To introduce a novel method using kilohertz sinusoidal gradient oscillations for NMR probe position tracking.
• To implement prospective motion correction for arbitrary MRI sequences without altering sequence timing.
• To combine motion tracking with concurrent field monitoring for robust image reconstruction.

Main Methods:

• Utilized an array of four field probes for real-time prospective motion correction in vivo.
• Employed kilohertz sinusoidal gradient oscillations for precise NMR probe tracking.
• Reconstructed images using both predetermined and concurrently measured k-space trajectories.

Main Results:

• Achieved probe position determination precision of 35–62 µm within 4.8 ms observation windows.
• Maximal single-axis measurement error was 595 µm root-mean-square.
• Generated artifact-free images despite substantial head motion, with equivalent quality from both trajectory methods.

Conclusions:

• NMR field probes and gradient oscillations effectively track and prospectively correct rigid-body motion.
• The proposed method enables concurrent motion detection and image encoding within standard MRI sequences.
• This technique offers a robust solution for motion-related artifacts in MRI.