Читать книгу Point-of-Care Ultrasound Techniques for the Small Animal Practitioner - Группа авторов - Страница 59

A comet‐tail artifact, also called a ring‐down artifact, is similar to reverberation. It is produced by the front and back of very strong reflectors with high acoustic impedance, such as metallic foreign bodies or implants, needles, and stylets during ultrasound‐guided procedures (see also Chapters 43 and 44), or strong reflectors with very low acoustic impedance relative to their adjacent soft tissues, such as gas in the lung, gas bubbles, or gas in the bowel. The reverberations are spaced very narrowly and blend into a small band. The greater the difference between the acoustic impedance of the reflecting structure and the surrounding tissues, the greater the number of reverberation echoes (Reef 1998) (see Figure 3.5).