Respiratory motion-resolved, self-gated 4D-MRI using rotating cartesian k-space (ROCK)

Fei Han; Ziwu Zhou; Minsong Cao; Yingli Yang; Ke Sheng; Peng Hu

doi:10.1002/mp.12139

Respiratory motion-resolved, self-gated 4D-MRI using rotating cartesian k-space (ROCK)

Med Phys. 2017 Apr;44(4):1359-1368. doi: 10.1002/mp.12139. Epub 2017 Mar 11.

Authors

Fei Han¹, Ziwu Zhou^{1

2}, Minsong Cao^{3

4}, Yingli Yang^{3

4}, Ke Sheng^{3

4}, Peng Hu^{1

4}

Affiliations

¹ Department of Radiological Sciences, David Geffen School of Medicine, University of California, 300 UCLA Medical Plaza Suite B119, Los Angeles, CA 90095, USA.
² Department of Bioengineering, University of California, 300 UCLA Medical Plaza Suite B119, Los Angeles, CA 90095, USA.
³ Department of Radiation Oncology, David Geffen School of Medicine, University of California, 200 UCLA Medical Plaza Suite B265, Los Angeles, CA 90095, USA.
⁴ Physics and Biology in Medicine Graduate Program, David Geffen School of Medicine, University of California, 300 UCLA Medical Plaza Suite B119, Los Angeles, CA 90095, USA.

Abstract

Purpose: To propose and validate a respiratory motion resolved, self-gated (SG) 4D-MRI technique to assess patient-specific breathing motion of abdominal organs for radiation treatment planning.

Methods: The proposed 4D-MRI technique was based on the balanced steady-state free-precession (bSSFP) technique and 3D k-space encoding. A novel rotating cartesian k-space (ROCK) reordering method was designed which incorporates repeatedly sampled k-space centerline as the SG motion surrogate and allows for retrospective k-space data binning into different respiratory positions based on the amplitude of the surrogate. The multiple respiratory-resolved 3D k-space data were subsequently reconstructed using a joint parallel imaging and compressed sensing method with spatial and temporal regularization. The proposed 4D-MRI technique was validated using a custom-made dynamic motion phantom and was tested in six healthy volunteers, in whom quantitative diaphragm and kidney motion measurements based on 4D-MRI images were compared with those based on 2D-CINE images.

Results: The 5-minute 4D-MRI scan offers high-quality volumetric images in 1.2 × 1.2 × 1.6 mm³ and eight respiratory positions, with good soft-tissue contrast. In phantom experiments with triangular motion waveform, the motion amplitude measurements based on 4D-MRI were 11.89% smaller than the ground truth, whereas a -12.5% difference was expected due to data binning effects. In healthy volunteers, the difference between the measurements based on 4D-MRI and the ones based on 2D-CINE were 6.2 ± 4.5% for the diaphragm, 8.2 ± 4.9% and 8.9 ± 5.1% for the right and left kidney.

Conclusion: The proposed 4D-MRI technique could provide high-resolution, high-quality, respiratory motion-resolved 4D images with good soft-tissue contrast and are free of the "stitching" artifacts usually seen on 4D-CT and 4D-MRI based on resorting 2D-CINE. It could be used to visualize and quantify abdominal organ motion for MRI-based radiation treatment planning.

Keywords: 4D-MRI; k-space binning; respiratory motion management; self-gating.

MeSH terms

Artifacts
Healthy Volunteers
Humans
Imaging, Three-Dimensional / methods*
Magnetic Resonance Imaging / methods*
Movement*
Phantoms, Imaging
Respiration*
Respiratory-Gated Imaging Techniques / methods*
Rotation*

Abstract

MeSH terms

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