Which statement describes harmonic imaging correctly?

Which statement describes harmonic imaging correctly?

• A. It uses the fundamental frequency to form the image
• B. It uses Doppler shifts for image formation
• C. It reduces frame rate
• D. It uses the harmonic of the transmitted frequency to form the image

Answer: (D)

Harmonic imaging relies on nonlinear propagation of ultrasound through tissue. As the wave travels, tissue generates harmonics—multiples of the transmitted frequency, most notably the second harmonic. The ultrasound system then forms the image from these harmonic frequencies rather than from the transmitted fundamental frequency. This approach improves resolution and reduces certain artifacts because the harmonics have different beam characteristics and are less affected by near-field clutter and side lobes. So the statement that describes harmonic imaging correctly is that it uses the harmonic of the transmitted frequency to form the image. The other ideas describe imaging methods or aspects (fundamental-frequency imaging, Doppler-based image formation, or frame rate) that are not the defining feature of harmonic imaging.

Harmonic imaging relies on nonlinear propagation of ultrasound through tissue. As the wave travels, tissue generates harmonics—multiples of the transmitted frequency, most notably the second harmonic. The ultrasound system then forms the image from these harmonic frequencies rather than from the transmitted fundamental frequency. This approach improves resolution and reduces certain artifacts because the harmonics have different beam characteristics and are less affected by near-field clutter and side lobes.

So the statement that describes harmonic imaging correctly is that it uses the harmonic of the transmitted frequency to form the image. The other ideas describe imaging methods or aspects (fundamental-frequency imaging, Doppler-based image formation, or frame rate) that are not the defining feature of harmonic imaging.