Direct visualization of strain waves by magnetic resonance elastography (MRE)

For thousands of years palpation has been used to find pathology in the human body. The longevity of palpation results from the sensitivity of mechanical properties of tissues to pathologic processes. Changes in elasticity of the tissues is what is detected by palpation. Many regions of the body are not accessible to palpation because of depth or protection, for instance of the brain by the skull. We describe a new method termed Magnetic Resonance Elastography, which can measure the three-dimensional displacement of propagating low frequency strain waves in human tissue. Wavelength can be calculated from cyclic displacements as small as 100 nanometers resulting in estimates of elasticity deep within the body. The method may provide noninvasive palpation anywhere in the body