Toward accurate and fast velocity quantification with 3D ultrashort TE phase-contrast imaging

Katja Degenhardt, Simon Schmidt, Christoph S. Aigner, Fabian J. Kratzer, Daniel P. Seiter, Max Mueller, Christoph Kolbitsch, Armin M. Nagel, Oliver Wieben, Tobias Schaeffter, Jeanette Schulz-Menger, Sebastian Schmitter

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: Traditional phase-contrast MRI is affected by displacement artifacts caused by non-synchronized spatial- and velocity-encoding time points. The resulting inaccurate velocity maps can affect the accuracy of derived hemodynamic parameters. This study proposes and characterizes a 3D radial phase-contrast UTE (PC-UTE) sequence to reduce displacement artifacts. Furthermore, it investigates the displacement of a standard Cartesian flow sequence by utilizing a displacement-free synchronized-single-point-imaging MR sequence (SYNC-SPI) that requires clinically prohibitively long acquisition times. Methods: 3D flow data was acquired at 3T at three different constant flow rates and varying spatial resolutions in a stenotic aorta phantom using the proposed PC-UTE, a Cartesian flow sequence, and a SYNC-SPI sequence as reference. Expected displacement artifacts were calculated from gradient timing waveforms and compared to displacement values measured in the in vitro flow experiments. Results: The PC-UTE sequence reduces displacement and intravoxel dephasing, leading to decreased geometric distortions and signal cancellations in magnitude images, and more spatially accurate velocity quantification compared to the Cartesian flow acquisitions; errors increase with velocity and higher spatial resolution. Conclusion: PC-UTE MRI can measure velocity vector fields with greater accuracy than Cartesian acquisitions (although pulsatile fields were not studied) and shorter scan times than SYNC-SPI. As such, this approach is superior to traditional Cartesian 3D and 4D flow MRI when spatial misrepresentations cannot be tolerated, for example, when computational fluid dynamics simulations are compared to or combined with in vitro or in vivo measurements, or regional parameters such as wall shear stress are of interest.

Original languageEnglish (US)
Pages (from-to)1994-2009
Number of pages16
JournalMagnetic resonance in medicine
Volume91
Issue number5
DOIs
StatePublished - May 2024

Bibliographical note

Publisher Copyright:
© 2024 Physikalisch-Technische Bundesanstalt (PTB) and The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.

Keywords

  • 4D flow MRI
  • GIRF
  • PC-UTE
  • displacement artifact
  • flow artifact
  • gradient imperfections

PubMed: MeSH publication types

  • Journal Article

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