Direct comparison of respiration-correlated four-dimensional magnetic resonance imaging reconstructed using concurrent internal navigator and external bellows Journal Article


Authors: Li, G.; Wei, J.; Olek, D.; Kadbi, M.; Tyagi, N.; Zakian, K.; Mechalakos, J.; Deasy, J. O.; Hunt, M.
Article Title: Direct comparison of respiration-correlated four-dimensional magnetic resonance imaging reconstructed using concurrent internal navigator and external bellows
Abstract: Purpose To compare the image quality of amplitude-binned 4-dimensional magnetic resonance imaging (4DMRI) reconstructed using 2 concurrent respiratory (navigator and bellows) waveforms. Methods and Materials A prospective, respiratory-correlated 4DMRI scanning program was used to acquire T2-weighted single-breath 4DMRI images with internal navigator and external bellows. After a 10-second training waveform of a surrogate signal, 2-dimensional MRI acquisition was triggered at a level (bin) and anatomic location (slice) until the bin-slice table was completed for 4DMRI reconstruction. The bellows signal was always collected, even when the navigator trigger was used, to retrospectively reconstruct a bellows-rebinned 4DMRI. Ten volunteers participated in this institutional review board–approved 4DMRI study. Four scans were acquired for each subject, including coronal and sagittal scans triggered by either navigator or bellows, and 6 4DMRI images (navigator-triggered, bellows-rebinned, and bellows-triggered) were reconstructed. The simultaneously acquired waveforms and resulting 4DMRI quality were compared using signal correlation, bin/phase shift, and binning motion artifacts. The consecutive bellows-triggered 4DMRI scan was used for indirect comparison. Results Correlation coefficients between the navigator and bellows signals were found to be patient-specific and inhalation-/exhalation-dependent, ranging from 0.1 to 0.9 because of breathing irregularities (>50% scans) and commonly observed bin/phase shifts (−1.1 ± 0.6 bin) in both 1-dimensional waveforms and diaphragm motion extracted from 4D images. Navigator-triggered 4DMRI contained many fewer binning motion artifacts at the diaphragm than did the bellows-rebinned and bellows-triggered 4DMRI scans. Coronal scans were faster than sagittal scans because of the fewer slices and higher achievable acceleration factors. Conclusions Navigator-triggered 4DMRI contains substantially fewer binning motion artifacts than bellows-rebinned and bellows-triggered 4DMRI, primarily owing to the deviation of the external from the internal surrogate. The present study compared 2 concurrent surrogates during the same 4DMRI scan and their resulting 4DMRI quality. The navigator-triggered 4DMRI scanning protocol should be preferred to the bellows-based, especially for coronal scans, for clinical respiratory motion simulation. © 2016 Elsevier Inc.
Keywords: magnetic resonance imaging; correlation coefficient; image processing; image reconstruction; respiratory motions; bellows; methods and materials; motion artifact; patient specific; diaphragms; bins; institutional review boards; magnetic levitation vehicles; acceleration factors; signal correlation
Journal Title: International Journal of Radiation Oncology, Biology, Physics
Volume: 97
Issue: 3
ISSN: 0360-3016
Publisher: Elsevier Inc.  
Date Published: 2017-03-01
Start Page: 596
End Page: 605
Language: English
DOI: 10.1016/j.ijrobp.2016.11.004
PROVIDER: scopus
PMCID: PMC5288126
PUBMED: 28011048
DOI/URL:
Notes: Article -- Export Date: 2 February 2017 -- Source: Scopus
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MSK Authors
  1. Guang Li
    98 Li
  2. Kristen L Zakian
    82 Zakian
  3. Joseph Owen Deasy
    524 Deasy
  4. Margie A Hunt
    287 Hunt
  5. Neelam Tyagi
    151 Tyagi
  6. Devin J Olek
    5 Olek