Which artifact results from repeated reflections between strong reflectors, creating multiple identical echoes over time?

• A. Reverberation
• B. Refraction
• C. Scattering
• D. Shadowing

Answer: (A)

Reverberation happens when the ultrasound wave bounces back and forth between two strong reflectors. Each bounce sends back an echo that returns a moment later, so a series of echoes appears at increasing depths with equal time spacing. The result is multiple identical echoes stacked over time, often seen as a ladder- or comet-tail–like pattern behind the reflecting surface. The echoes weaken with each bounce, but their spacing remains constant because it reflects the round-trip travel time between the two reflectors.

This differs from refraction, which bends the beam and shifts structures; scattering, which creates a speckled appearance from many tiny interfaces; and shadowing, which is a dark area behind a highly attenuating object. Reverberation is the artifact produced by repeated reflections between strong reflectors.