Introduction of a pseudo demons force to enhance deformation range for robust reconstruction of super-resolution time-resolved 4DMRI Journal Article

Authors: Li, G.; Sun, A.; Nie, X.; Moody, J.; Huang, K.; Zhang, S.; Sharma, S.; Deasy, J.
Article Title: Introduction of a pseudo demons force to enhance deformation range for robust reconstruction of super-resolution time-resolved 4DMRI
Abstract: Purpose: The purpose of this study was to enhance the deformation range of demons-based deformable image registration (DIR) for large respiration-induced organ motion in the reconstruction of time-resolved four-dimensional magnetic resonance imaging (TR-4DMRI) for multi-breath motion simulation. Methods: A demons-based DIR algorithm was modified to enhance the deformation range for TR-4DMRI reconstruction using the super-resolution approach. A pseudo demons force was introduced to accelerate the coarse deformation in a multi-resolution (n = 3) DIR approach. The intensity gradient of a voxel was applied to its neighboring (5 × 5 × 5) voxels with a weight of Gaussian probability profile (σ = 1 voxel) to extend the demons force, especially on those voxels that have little intensity gradience but high-intensity difference. A digital 4DMRI phantom with 3–8 cm diaphragmatic motions was used for DIR comparison. Six volunteers were scanned with two high-resolution (highR: 2 × 2 × 2 mm3) breath-hold (BH) 3DMR images at full inhalation (BHI) and full exhalation (BHE) and low-resolution (lowR: 5 × 5 × 5 mm3) free-breathing (FB) 3DMR cine images (2 Hz) under an IRB-approved protocol. A cross-consistency check (CCC) (BHI→FB←BHE), with voxel intensity correlation (VIC) and inverse consistency error (ICE), was introduced for cross-verification of TR-4DMRI reconstruction. Results: Using the digital phantom, the maximum deformable magnitude is doubled using the modified DIR from 3 to 6 cm at the diaphragm. In six human subjects, the first 15-iteration DIR using the pseudo force deforms 200 ± 150% more than the original force, and succeeds in all 12 cases, whereas the original demons-based DIR failed in 67% of tested cases. Using the pseudo force, high VIC (>0.9) and small ICE (1.6 ± 0.6 mm) values are observed for DIR of BHI&BHE, BHI→FB, and BHE→FB. The CCC identifies four questionable cases, in which two cases need further DIR refinement, without missing true negative. Conclusions: The introduction of a pseudo demons force enhances the largest deformation magnitude up to 6 cm. The cross-consistency check ensures the quality of TR-4DMRI reconstruction. Further investigation is ongoing to fully characterize TR-4DMRI for potential multi-breathing-cycle radiotherapy simulation. © 2018 American Association of Physicists in Medicine
Keywords: image-guided radiotherapy (igrt); deformable image registration (dir); multi-breath motion assessment; time-resolved four-dimensional magnetic resonance image (tr-4dmri)
Journal Title: Medical Physics
Volume: 45
Issue: 11
ISSN: 0094-2405
Publisher: American Association of Physicists in Medicine  
Date Published: 2018-11-01
Start Page: 5197
End Page: 5207
Language: English
DOI: 10.1002/mp.13179
PUBMED: 30203474
PROVIDER: scopus
PMCID: PMC6278596
Notes: Article -- Export Date: 3 December 2018 -- Source: Scopus
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MSK Authors
  1. Guang Li
    54 Li
  2. Joseph Owen Deasy
    279 Deasy
  3. Shirong Zhang
    4 Zhang
  4. Jason Frank Moody
    5 Moody
  5. August Gaoquan Sun
    4 Sun
  6. Xingyu Nie
    4 Nie
  7. Satyam Sharma
    2 Sharma
  8. Kirk Kuan-ru Huang
    3 Huang