What term describes results from decreased attenuation through a fluid-filled structure compared with surrounding tissue?

What term describes results from decreased attenuation through a fluid-filled structure compared with surrounding tissue?

• A. Acoustic shadowing
• B. Attenuation
• C. Acoustic enhancement
• D. Refraction

Answer: (C)

Acoustic enhancement occurs when a fluid-filled structure allows the ultrasound beam to pass with little attenuation, so deeper tissues return stronger echoes and the area beneath the fluid appears brighter. Fluids attenuate much less than surrounding soft tissue, so more sound energy reaches deeper tissues and the echoes from those tissues are amplified, creating a bright region under the fluid-filled structure. This is different from acoustic shadowing, which is a dark area behind a highly attenuating object; attenuation is the general loss of energy with depth, not a specific brightness change, and refraction is the bending of the beam at a boundary, not an increase in brightness under a fluid.

Acoustic enhancement occurs when a fluid-filled structure allows the ultrasound beam to pass with little attenuation, so deeper tissues return stronger echoes and the area beneath the fluid appears brighter. Fluids attenuate much less than surrounding soft tissue, so more sound energy reaches deeper tissues and the echoes from those tissues are amplified, creating a bright region under the fluid-filled structure. This is different from acoustic shadowing, which is a dark area behind a highly attenuating object; attenuation is the general loss of energy with depth, not a specific brightness change, and refraction is the bending of the beam at a boundary, not an increase in brightness under a fluid.