A generalization of pulse inversion Doppler

A generalization of pulse inversion Doppler is presented enabling the selective detection and combination of harmonic components of received echoes from tissue or ultrasound contrast agents. If phase shifts other than half a period (i.e. pulse inversion) are applied to the transmitted pulses of a color Doppler sequence, the harmonic components generated by tissue or ultrasound contrast agents are spread across the Doppler spectrum. This approach of interrogating these nonlinear systems has the advantage of the selective detection or combination of harmonic components by filtering in the Doppler domain (i.e. wall filtering). We propose a method, easily understood in the Doppler domain, of detecting and combining harmonic components to gain more tissue or contrast over tissue information and thus improve SNR, relative to conventional pulse inversion.