Application of DENSE-MR-elastography to the human heart

Benjamin Robert, Ralph Sinkus, Jean-Luc Gennisson, Mathias Fink

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

Typically, MR-elastography (MRE) encodes the propagation of monochromatic acoustic waves in the MR-phase images via sinusoidal gradients characterized by a detection frequency equal to the frequency of the mechanical vibration. Therefore, the echo time of a conventional MRE sequence is typically longer than the vibration period which is critical for heart tissue exhibiting a short T(2). Thus, fast acquisition techniques like the so-called fractional encoding of harmonic motions were developed for cardiac applications. However, fractional encoding of harmonic motions is limited since it is two orders of magnitude less sensitive to motion than conventional MRE sequences for low-frequency vibrations. Here, a new sequence is derived from the so-called displacement encoding with stimulated echoes (DENSE) sequence. This sequence is more sensitive to displacement than fractional encoding of harmonic motions, and its spectral specificity is equivalent to conventional MRE sequences. The theoretical spectral properties of this new motion-encoding technique are validated in a phantom and excised pork heart specimen. An excellent agreement is found for the measured displacement fields using classic MRE and displacement encoding with stimulated echoes MRE (8% maximum difference). In addition, initial in vivo results on a healthy volunteer clearly show propagating shear waves at 50 Hz. Thus, displacement encoding with stimulated echoes MRE is a promising technique for motion encoding within short T(2)* materials.
Original languageEnglish
Pages (from-to)1155-1163
Number of pages9
JournalMagnetic Resonance in Medicine
Volume62
Issue number5
DOIs
Publication statusPublished - Nov 2009

Keywords

  • Algorithms
  • Elastic Modulus
  • Elasticity Imaging Techniques
  • Heart
  • Humans
  • Image Enhancement
  • Image Interpretation, Computer-Assisted
  • Phantoms, Imaging
  • Reproducibility of Results
  • Sensitivity and Specificity

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