Point-of-Care Ultrasound Techniques for the Small Animal Practitioner. Группа авторов

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Название Point-of-Care Ultrasound Techniques for the Small Animal Practitioner
Автор произведения Группа авторов
Жанр Биология
Серия
Издательство Биология
Год выпуска 0
isbn 9781119461029



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      4 Nyland TG, Mattoon JS, Herrgesell EJ, et al. 2002. Physical principles, instrumentation, and safety of diagnostic ultrasound. In: Small Animal Diagnostic Ultrasound, 2nd edition, edited by Nyland TG, Mattoon JS. Philadelphia: WB Saunders, pp 1–18.

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      1 Volpicelli G, Elbarbary M, Blaivas M, et al. 2012. International evidence‐based recommendations for point‐of‐care lung ultrasound. Intensive Care Med 38:577–591.

      Robert M. Fulton

      In this chapter, we'll look at the fundamental laws governing wave dynamics and see how ultrasound artifacts are created. Ultrasound machines rely on several physical assumptions to assign the location and intensity of each received echo. These assumptions are that the received echoes have originated from within the main ultrasound beam, an echo returns to the transducer after a single reflection, the depth of an object is directly related to the amount of time for an ultrasound pulse to return to the transducer, the speed of sound in tissue is constant (1540 m/sec), the sound beam and its echo travel in a straight path, and the acoustic energy in an ultrasound field is uniformly attenuated (Feldman et al. 2009). Artifacts may be grouped by the most important principles leading to their formation, including attenuation, velocity or propagation, and artifacts associated with multiple echoes. Many artifacts can be grouped by their association with air or fluid, making learning them easier.

       What POCUS Basic Ultrasound Artifacts Can Do

       Provide a basic understanding of how artifacts are formed to allow better interpretation of the ultrasound image.

       What POCUS Basic Ultrasound Artifacts Cannot Do

       Cannot provide an in‐depth discussion of ultrasound artifacts.

       Cannot account for what artifacts your ultrasound machine's software is most biased towards.

       Indications

       Provide a basic understanding of ultrasound principles and common artifacts to maximize accurate image interpretation.

       Objectives

       Provide a basic understanding of how common ultrasound artifacts are formed to avoid image misinterpretation of artifacts for abnormalities.

       Shadowing, “Clean” and “Dirty”

       Bone or Stone Interface: Clean Shadowing

Image described by caption and surrounding text.

      Source: Courtesy of Dr Sarah Young, Echo Service for Pets, Ojai, California.

       Air Interface: Dirty Shadowing

      On the other hand, soft tissue–air interfaces are more variable in their degree of reflection, with some of the ultrasound waves incompletely moving through the air‐filled structure, unlike the complete reflection at bone (or stone). Thus, reverberations occur distal to the air interface, creating a “dirty shadow” (Penninck 2002) (see Figure 3.1).

       Edge Shadowing: Fluid‐Filled Structures

Image described by caption.