Correction of Respiratory Motion in Free-Breathing DCE-MRI Using a Pilot-Tone Coil

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging
• Biomedical Engineering

Background:

• Abdominopelvic MRI is challenged by respiratory motion artifacts.
• Current self-navigation methods fail in dynamic contrast-enhanced (DCE) scans due to signal changes from contrast agents.
• Accurate respiratory motion tracking is crucial for free-breathing DCE-MRI.

Purpose of the Study:

• To investigate a pilot-tone (PT) transmitter integrated into MRI receive coils for respiratory motion tracking.
• To develop a pipeline for extracting respiratory curves from PT signals.
• To apply this technique for motion-corrected free-breathing abdominal DCE-MRI.

Main Methods:

• A pilot-tone (PT) transmitter was integrated into MRI receive coils.
• A pipeline was developed to extract respiratory motion curves from the PT signal amplitude.
• Motion-weighted GRASP (Golden-angle Radial Acquisition with Sparsity-based Reconstruction) was used for image reconstruction, incorporating PT-derived respiratory curves.

Main Results:

• The PT technique successfully extracted respiratory curves during contrast injection.
• Motion-weighted DCE GRASP reconstructions using PT data showed improved image sharpness and temporal consistency.
• Improvements were observed qualitatively and quantitatively, particularly in diaphragmatic and kidney boundary regions.

Conclusions:

• The pilot-tone (PT) technique provides accurate respiratory motion detection during contrast-enhanced MRI.
• This method effectively reduces motion blurring in free-breathing dynamic DCE-MRI.
• The PT technique is clinically applicable, requiring no external sensors.