MAGNETIC-RESONANCE ELASTOGRAPHY BY DIRECT VISUALIZATION OF PROPAGATING ACOUSTIC STRAIN WAVES

A nuclear magnetic resonance imaging (MRI) method is presented for qua ntitatively mapping the physical response of a material to harmonic me chanical excitation. The resulting images allow calculation of regiona l mechanical properties. Measurements of shear modulus obtained with t he MRI technique in gel materials correlate with independent measureme nts of static shear modulus. The results indicate that displacement pa tterns corresponding to cyclic displacements smaller than 200 nanomete rs can be measured. The findings suggest the feasibility of a medical imaging technique for delineating elasticity and other mechanical prop erties of tissue.