Influence of the transducer near field in MR elastography wave images
Sack I, Rump J, Papazoglou S, Klatt D, Hamhaber U, Braun J
Institute of Radiology
In MR elastography (MRE) bulk shear waves radiated by a harmonic surface load are used for testing mechanical properties of soft tissue. Here, it is shown by MRE experiments on gelatine that a longitudinally polarized wave exists in vicinity of the source with wavelengths comparable to the shear wave. We attribute this wave partly to the near field of an extended transducer. It is shown that within the audio regime of MRE and at distances up to one shear-wave length from the transducer the near field might yield to an overestimation of the real shear stiffness of the examined tissue.