An embedded optical tracking system for motion-corrected magnetic resonance imaging at 7T

Area of Science:

• Medical Imaging
• Biomedical Engineering

Background:

• Motion artifacts are a significant challenge in Magnetic Resonance Imaging (MRI), particularly for head scans.
• Optical tracking systems have shown promise in reducing these artifacts through prospective motion correction.

Purpose of the Study:

• To evaluate a novel, home-built optical embedded tracking system for prospective motion correction in MRI.
• To assess the system's performance and its impact on image quality in vivo.

Main Methods:

• An optical embedded tracking system was developed for high-speed image processing within a 7 Tesla (7T) MRI scanner bore.
• In vivo MR volumes were acquired using a modified 3D FLASH sequence, with interleaved corrected and uncorrected data.
• Image quality was assessed by comparing corrected and uncorrected scans.

Main Results:

• The system demonstrated a low latency of (19 ± 5) ms between motion detection and slice position correction.
• Tracking noise was minimal, with a standard deviation of ≤ 10 μm/0.005° during scanning.
• Prospective motion correction resulted in a 16% average improvement in edge strength, despite participants attempting to remain still.

Conclusions:

• The novel embedded optical tracking system effectively reduces motion artifacts in MRI.
• Prospective motion correction using this system considerably improved in vivo MR image quality.
• The study validates a new method for assessing prospective motion correction efficacy.