title: Measurement of pulsatile motion with millisecond resolution by MRI.
abstract: We investigated a technique based on phase-contrast cine MRI combined with deconvolution of the phase shift waveforms to measure rapidly varying pulsatile motion waveforms. The technique does not require steady-state displacement during motion encoding. Simulations and experiments were performed in porcine liver samples in view of a specific application, namely the observation of transient displacements induced by acoustic radiation force. Simulations illustrate the advantages and shortcomings of the methods. For experimental validation, the waveforms were acquired with an ultrafast ultrasound scanner (Supersonic Imagine Aixplorer), and the rates of decay of the waveforms (relaxation time) were compared. With bipolar motion-encoding gradient of 8.4 ms, the method was able to measure displacement waveforms with a temporal resolution of 1 ms over a time course of 40 ms. Reasonable agreement was found between the rate of decay of the waveforms measured in ultrasound (2.8 ms) and in MRI (2.7-3.3 ms).
authors.affiliation: INSERM, U1032, Lyon, France. Remi.Souchon@inserm.fr
authors.forename: Rémi
authors.initials: R
authors.lastname: Souchon
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gennisson
authors.forename: Mickael
authors.initials: M
authors.lastname: Tanter
authors.forename: Rares
authors.initials: R
authors.lastname: Salomir
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Chapelon
authors.forename: Olivier
authors.initials: O
authors.lastname: Rouvière
mesh_terms: D000465:Algorithms; D000818:Animals; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008099:Liver / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009068:Movement / Q000502:physiology; D011673:Pulsatile Flow / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014783:Viscosity