Pulse inversion harmonics imaging retains which frequency components?

Pulse inversion harmonics imaging retains which frequency components?

• A. Fundamental frequencies
• B. Side lobe frequencies
• C. Harmonic frequencies
• D. Noise frequencies

Answer: (C)

Pulse inversion imaging relies on canceling linear echoes while letting nonlinear responses shine through. By sending two pulses with opposite phase and summing their echoes, the linear component—the fundamental frequency—cancels out because it responds symmetrically to the opposite pulses. Nonlinear scattering, such as from microbubble contrast agents or certain tissue structures, generates frequency components that are multiples of the fundamental. These nonlinear echoes do not cancel when the two opposite-phase pulses are added, so the harmonic frequencies are retained and become the basis of the image. In short, this technique preserves the harmonic frequencies while the fundamental is suppressed, which is why harmonic frequencies are retained.

Pulse inversion imaging relies on canceling linear echoes while letting nonlinear responses shine through. By sending two pulses with opposite phase and summing their echoes, the linear component—the fundamental frequency—cancels out because it responds symmetrically to the opposite pulses. Nonlinear scattering, such as from microbubble contrast agents or certain tissue structures, generates frequency components that are multiples of the fundamental. These nonlinear echoes do not cancel when the two opposite-phase pulses are added, so the harmonic frequencies are retained and become the basis of the image. In short, this technique preserves the harmonic frequencies while the fundamental is suppressed, which is why harmonic frequencies are retained.