Which display mode enhances contrast resolution and reduces artifacts in ultrasound imaging?

• A. Brightness mode
• B. A-mode
• C. Harmonic mode
• D. C-mode

Answer: (C)

Harmonic mode is used in ultrasound imaging to enhance contrast resolution and reduce artifacts. This is achieved by utilizing the nonlinear propagation of sound waves, which allows for the generation of harmonic frequencies that are multiples of the fundamental frequency. When the ultrasound waves interact with tissues, they create additional frequencies that are captured and used to form images.

These harmonic frequencies provide clearer and more detailed images because they are less affected by scattering and other artifacts that can occur at the fundamental frequency. As a result, harmonic imaging is particularly effective in visualizing structures with higher contrast, correlating to improved diagnostic capabilities. This is why harmonic mode is favored in clinical practice, as it facilitates better visualization of structures and minimizes the interference from surrounding tissues or structures that may obscure the primary image.