2nd Harmonic Imaging

Abstract

At low flow velocities, the separation of clutter from flow is insufficient using conventional signal evaluation. When looking at echo enhancers for characteristic properties which would permit improved differentiation of tissue on the one hand and the presence of microbubbles on the other, attention should be paid to the nature of wave propagation. When a wave travels through a medium, both overtones and undertones are produced depending on physical conditions. If the wave is only observed at its transmit frequency then it is seen as a linear propagation. The term non-linear propagation is used to describe waves with all their frequency elements.