What is the ultrasound imaging method that uses the harmonic of the transmitted frequency to create the image called?

• A. Doppler imaging
• B. Tissue harmonics
• C. B-mode imaging
• D. Elastography

Answer: (B)

Ultrasound tissue harmonic imaging relies on the nonlinear way sound travels through tissue. As the transmitted wave moves, the tissue distorts the waveform and generates higher-frequency components, or harmonics, of the original (transmitted) frequency. The system then receives and uses these harmonic signals—often the second harmonic—to construct the image. Because the harmonics come from nonlinear propagation and are less affected by near-field artifacts, this technique yields sharper borders, better contrast, and improved resolution compared with standard imaging that uses the fundamental frequency.

In other words, the image is built from the tissue-generated harmonics rather than the direct reflected fundamental frequency. This is distinct from Doppler imaging, which measures frequency shifts caused by motion (flow), from standard B-mode imaging that relies on the fundamental frequency, and from elastography, which assesses tissue stiffness.