Ring down artifact

Last revised by Sonam Vadera on 31 Oct 2020

Ring down artifact is a special type of resonance artifact. Its appearance is similar to the ladder-like reverberation of comet-tail artifact, but it is produced by a completely different mechanism.

The artifact is only associated with gas bubbles, and occurs when an ultrasound pulse encounters a "horn" or "bugle" shaped fluid collection that is trapped between an inverted tetrahedron of 4 bubbles (3 on top and 1 nestled deep to them). The trapped fluid resonates, emitting a continuous signal back to the transducer. Whereas the transducer pulse is broad spectrum, the returning signal consists of one or more discrete (resonant) frequencies. "Beats" between these frequencies produce the variable appearance of the ring down. There is no "reverberation" ( i.e. multiple reflectances).

This artifact can be eliminated by angling the ultrasound probe.

See also

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