Evaluation of a rapid, multiphase MRE sequence in a heart-simulating phantom.
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.
Kolipaka
Arunark
A
Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
McGee
Kiaran P
KP
Araoz
Philip A
PA
Glaser
Kevin J
KJ
Manduca
Armando
A
Ehman
Richard L
RL
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