title: Evaluation of a rapid, multiphase MRE sequence in a heart-simulating phantom.
abstract: The aims of this study were to validate stiffness estimates of a phantom undergoing cyclic deformation obtained using a multiphase magnetic resonance elastography (MRE) imaging sequence by comparison with those obtained using a single-phase MRE sequence and to quantify the stability of the multiphase-derived stiffness estimates as a function of deformation frequency and imaging parameters. A spherical rubber shell of 10 cm diameter and 1 cm thickness was connected to a computerized flow pump to produce cyclic pressure variations within the phantom. The phantom was imaged at cyclic pressures between 18-72 bpm using single-phase and multiphase MRE acquisitions. The shear stiffness of the phantom was resolved using a spherical shell wave inversion algorithm. Shear stiffness was averaged over the slice of interest and plotted against pressure within the phantom. A linear correlation was observed between stiffness and pressure. Good correlation (R(2) = 0.98) was observed between the stiffness estimates obtained using the standard single-phase and the multiphase pulse sequences. Stiffness estimates obtained using multiphase MRE were stable when the fraction of the deformation period required for acquisition of a single image was not greater than 42%. The results demonstrate the potential of multiphase MRE technique for imaging dynamic organs, such as the heart.
authors: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors: Arunark
authors: A
authors: Kolipaka
authors: Kiaran P
authors: KP
authors: McGee
authors: Philip A
authors: PA
authors: Araoz
authors: Kevin J
authors: KJ
authors: Glaser
authors: Armando
authors: A
authors: Manduca
authors: Richard L
authors: RL
authors: Ehman
mesh_terms: D000465:Algorithms; D004548:Elasticity / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical