Ultrasonography is a diagnostic and therapeutic medium, whereby an ultrasonic image is produced by the reflection of high-frequency sound waves at density interfaces between two tissues. Fluid is an excellent medium for transmission of sound waves and fluid-filled structures appear black or anechoic on the ultrasonographic image. Gas transmits little but produces severe attenuation of the sound beam. Other tissues are seen as various shades of grey depending on their ability to reflect sound waves.
Ultrasound is a form of radiant energy at frequencies >20,000 cycles/s (Hertz or Hz). For diagnostic ultrasonography, the reflections of high frequency ultrasonic waves are recorded as they bounce off the target tissues. Lower frequencies provide greater penetration, whereas higher frequencies provide lower penetration and greater detail.
Ultrasonography is most commonly used for assessment of flexor tendon injuries and for the monitoring of their healing. In this way it can be ensured that the healing tendon is loaded within its capability, and not beyond, during the healing process. Ultrasonographic examination of bone surfaces, joints and synovial structures, allows the assessment of ligaments and their points of insertion, and of the surfaces of bones, their cartilage and their synovial structures. In this way assessment of joint diseases and fractures may be aided. In addition, other soft structures such as the muscles and extensor tendons can be imaged if there is anything to suggest that there is a problem in this area. The investigation of potential causes of superficial swellings is aided and the recognition of muscular problems and the depths of traumatic injuries can be assessed.
To find out more on this topic, watch out for The Webinar Vet’s latest webinar on Ultrasound in the foal by Kevin Corley on the 10th April at 8pm.
For further information on equine ultrasonography check out this related content available on Vetlexicon Equis: