Self-navigated 4D cartesian imaging of periodic motion in the body trunk using partial k-space compressed sensing

Magn Reson Med. 2017 Aug;78(2):632-644. doi: 10.1002/mrm.26406. Epub 2016 Sep 25.

Abstract

Purpose: To enable fast and flexible high-resolution four-dimensional (4D) MRI of periodic thoracic/abdominal motion for motion visualization or motion-corrected imaging.

Methods: We proposed a Cartesian three-dimensional k-space sampling scheme that acquires a random combination of k-space lines in the ky/kz plane. A partial Fourier-like constraint compacts the sampling space to one half of k-space. The central k-space line is periodically acquired to allow an extraction of a self-navigated respiration signal used to populate a k-space of multiple breathing positions. The randomness of the acquisition (induced by periodic breathing pattern) yields a subsampled k-space that is reconstructed using compressed sensing. Local image evaluations (coefficient of variation and slope steepness through organs) reveal information about motion resolvability. Image quality is inspected by a blinded reading. Sequence and reconstruction method are made publicly available.

Results: The method is able to capture and reconstruct 4D images with high image quality and motion resolution within a short scan time of less than 2 min. These findings are supported by restricted-isometry-property analysis, local image evaluation, and blinded reading.

Conclusion: The proposed method provides a clinical feasible setup to capture periodic respiratory motion with a fast acquisition protocol and can be extended by further surrogate signals to capture additional periodic motions. Retrospective parametrization allows for flexible tuning toward the targeted applications. Magn Reson Med 78:632-644, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Keywords: compressed sensing; motion visualization; partial Fourier.

MeSH terms

  • Algorithms
  • Humans
  • Imaging, Three-Dimensional / methods*
  • Magnetic Resonance Imaging / methods*
  • Movement / physiology*
  • Respiration
  • Retrospective Studies
  • Torso / diagnostic imaging*