Ultra high speed imaging of elasticity

Ultrafast ultrasonic imaging seems to have a strong potential for medical imaging applications. During the past five years, it has been applied successfully to quantitative assessment of soft tissues elasticity. An ultrafast ultrasonic scanner was built in our lab for quantitatively mapping the shear elasticity of soft tissues. The ultrafast Scanner provides images of the echogenecity of tissues similar to a standard echographic device but with a 200 times higher a frame rate. It allows to detect fast tissue motion induced by low frequency shear waves inside the body. From these displacements, a shear elasticity map is constructed using inverse problem algorithms. Preliminary in vivo results in breast demonstrate that this technique, known as transient elastography, is very sensitive to the presence of hard tumors. The same technique can also be combined with remote palpation induced par ultrasonic radiation pressure to replace the usual external vibrating system The same probe allows both to generate and detect shear waves propagation by using an unusual emission-reception sequence.