Reverberation effect (audio)

Reverberation effect is very common in everyday life. In empty rooms and large halls it is often noticed. Converting the 'audible' effect into a 'visual' effect in the ultrasound image is what makes it a bit unfamiliar.

You can listen to a sample sound without the reverberation effect here. The same sound with the reverberation effect is demonstrated here. You can listen to the two sample sounds in succession here.

You will notice that with reverberation, there is an 'echo-like' effect, by which the original sound seems to be 'prolonged', with gradual attenuation of the intensity of sound as time passes. This happens due to repeated reflection of sound waves on the room's or hall's walls. The same happens within the core of a needle. However, time translates into distance in the ultrasound image. Therefore, there is repetition of the ultrasound image of the needle, with gradual fading of the image as we go away from the transducer.