Type:
Educational Exhibit
Keywords:
Calcifications / Calculi, Artifacts, Physics, Ultrasound, Ultrasound physics, Anatomy, Abdomen
Authors:
S. Méndez Garrido1, J. Arce Duran2, A. Talegón Meléndez1; 1Sevilla/ES, 2Seville/ES
DOI:
10.1594/ecr2013/C-2288
Conclusion
Comet tail and Ring-Down artifact usually are used as synonyms,
due to their similar appearance on ultrasound.
But their physical basis are completely different and the mechanism that produce them:
- Comet tail artifact is a form of reverberation; therefore it has the same production basis,
i.e,
repeated trips between the transducer and two reflective surfaces.
- Ring-down artifact occurs when the ultrasound beam excites the liquid trapped between gas bubbles,
producing the liquid to vibrate or resonate.
- Metallic elements/calcifications cause comet tail artifact,
being thus useful for diagnosing from foreign bodies,
metal clips of suture,
catheters… to calculus or granulomas.
- Gas is responsible for Ring-Down artifact.
Its display can translate from gas than can be found in physiological situations (for example inside bowel),
after surgical procedures (aerobilia after cholecystectomy or hepaticojejunostomy) or pathological processes (pneumatosis intestinalis,
emphysematous cholecystitis…).
It is necessary to emphasize that knowledge of clinical data and patient history are essential to guide in the ethiology.