Which artifact is related to beam attenuation?

• A. Comet tail
• B. Aliasing
• C. Reverberation
• D. Enhancement

Answer: (D)

Attenuation is the gradual loss of ultrasound energy as it travels through tissue. When the beam passes through a region with low attenuation, more energy reaches the deeper tissues and returns stronger echoes from those interfaces. That increased brightness behind the low-attenuation area is called enhancement. It helps show fluid-filled structures, which attenuate less, by making the echoes from deeper structures appear brighter.

The other phenomena come from different mechanisms: comet tail results from closely spaced strong reflectors creating a chain of echoes; aliasing is a Doppler display artifact caused by insufficient sampling frequency; reverberation stems from multiple internal reflections between two strong reflectors, producing repeated, evenly spaced echoes. Thus, enhancement is the artifact tied to beam attenuation.