Pulse inversion Doppler: a new method for detecting nonlinear echoes from microbubble contrast agents

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 46; no. 2; pp. 372 - 382
• Main Authors: Simpson, D.H., Chien Ting Chin, Burns, P.N.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.1999; Institute of Electrical and Electronics Engineers
• Subjects: Acoustic scattering; Acoustical measurements and instrumentation; Acoustics; Bandwidth; Biological and medical sciences; Broadband; Contrast agents; Doppler; Doppler effect; Echo suppression; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Harmonics; High-resolution imaging; Image resolution; Imaging techniques; Inversions; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Microorganisms; Miscellaneous. Technology; Nonlinearity; Nyquist diagrams; Particle scattering; Passband; Physics; Power system harmonics; Pulse inverters; Pulse measurements; Signal detection; Signal resolution; Tissue; Ultrasonic imaging; Ultrasonic investigative techniques; Bubble; Frequency shift; Medical imagery; Measurement method; Doppler effect; Experimental study; Acoustic image; Modeling; Ultrasound; Color image; Contrast media
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/58.753026

A novel technique for the selective detection of ultrasound contrast agents, called pulse inversion Doppler, has been developed. In this technique, a conventional Doppler or color Doppler pulse sequence is modified by inverting every second transmit pulse. Either conventional or harmonic Doppler processing is then performed on the received echoes. In the resulting Doppler spectra, Doppler shifts from linear and nonlinear scattering are separated into two distinct regions that can be analyzed separately or combined to estimate the ratio of nonlinear to linear scattering from a region of tissue. The maximum Doppler shift that can be detected is 1/2 the normal Nyquist limit. This has the advantage over conventional harmonic Doppler that it can function over the entire bandwidth of the echo signal, thus achieving superior spatial resolution in the Doppler image. In vitro measurements comparing flowing agent and cellulose particles suggest that pulse inversion Doppler can provide 3 to 10 dB more agent to tissue contrast than harmonic imaging with similar pulses. Similar measurements suggest that broadband pulse inversion Doppler can provide up to 16 dB more contrast than broadband conventional Doppler. Nonlinear propagation effects limit the maximum contrast obtainable with both harmonic and pulse inversion Doppler techniques.