What artifact might be observed when a sound beam encounters a strong difference in acoustic impedance?

The observation of an artifact when a sound beam encounters a strong difference in acoustic impedance is linked to the enhancement artifact. Acoustic impedance refers to how much resistance a medium provides to the passage of sound waves. When a sound beam transitions from one medium to another—especially between tissues of significantly different acoustic impedance—the behavior of the sound waves can change dramatically.

In instances where there is a strong difference in acoustic impedance, certain tissues can cause an increase in the amplitude of the returning echoes. This increase leads to an enhancement artifact, where areas behind a structure with high acoustic impedance appear brighter on the ultrasound image than they actually are. This can often be seen behind fluid-filled structures, such as cysts or vessels, where the fluid provides little resistance to the sound waves.

To further grasp the concept, consider that shadowing artifact typically occurs when sound waves are fully absorbed or reflected by a dense structure, leading to an absence of echoes in the area behind that structure. Reverberation artifact arises from multiple reflections of sound waves between surfaces, creating a series of equally spaced echoes. Aliasing artifact is related to Doppler ultrasound and occurs when the frequency of the returning echoes exceeds the Nyquist limit, resulting in a misrepresentation of the velocities.

Understanding these various types of