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3D Cine Magnetic Resonance Imaging of Respiratory Motion in Mechanically Ventilated Mice and Rats
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Respiratory motion-resolved, self-gated 4D-MRI using rotating cartesian k-space (ROCK).
Fei Han1, Ziwu Zhou1,2, Minsong Cao3,4
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, 300 UCLA Medical Plaza Suite B119, Los Angeles, CA 90095, USA.
Medical Physics
|January 31, 2017
Summary
This study introduces a new self-gated 4D-MRI technique for precise visualization of abdominal organ motion during breathing. The method accurately quantifies patient-specific motion, improving radiation treatment planning.
Area of Science:
- Medical Imaging
- Radiotherapy Physics
- Biomedical Engineering
Background:
- Accurate assessment of patient-specific abdominal organ motion is crucial for effective radiation therapy planning.
- Current 4D imaging techniques can suffer from artifacts and limitations in resolution and soft-tissue contrast.
- Developing novel 4D Magnetic Resonance Imaging (4D-MRI) methods is essential for improving motion management in radiotherapy.
Purpose of the Study:
- To propose and validate a novel self-gated (SG) 4D-MRI technique for respiratory motion-resolved imaging of abdominal organs.
- To assess patient-specific breathing motion for enhanced radiation treatment planning.
- To provide high-quality, high-resolution 4D images free from common artifacts.
Main Methods:
- A self-gated (SG) 4D-MRI technique utilizing balanced steady-state free-precession (bSSFP) and 3D k-space encoding was developed.
- A rotating cartesian k-space (ROCK) reordering method was employed, using k-space centerline as a motion surrogate for retrospective data binning.
- Reconstruction involved joint parallel imaging and compressed sensing with spatial and temporal regularization, validated in phantom and volunteer studies.
Main Results:
- The 5-minute 4D-MRI scan produced high-quality volumetric images (1.2 × 1.2 × 1.6 mm³) across eight respiratory phases with excellent soft-tissue contrast.
- Phantom experiments showed motion amplitude measurements within expected data binning differences.
- In healthy volunteers, 4D-MRI measurements closely agreed with 2D-CINE, with differences of 6.2 ± 4.5% (diaphragm) and 8.2-8.9% (kidneys).
Conclusions:
- The proposed SG 4D-MRI technique delivers high-resolution, artifact-free 4D images with superior soft-tissue contrast.
- This technique enables accurate visualization and quantification of abdominal organ motion.
- It holds significant potential for improving MRI-based radiation treatment planning by providing patient-specific motion data.
