Ultrasonography

Ultrasonography uses high frequency sound waves (usually 2-10Mhz, which is far outside the human hearing range) to produce images of different tissues. An ultrasound probe (or transducer) generates a series of ultrasound pulses. The energy produced by these pulses passes into the horse and is then reflected back to the transducer, from different tissue interfaces (such as a fluid/soft tissue interface). The returning energy from the ultrasound is then processed into electrical energy, which is then displayed as an image of the area of the horse being scanned on the computer screen.

Ultrasonography is very useful in the diagnostic evaluation of soft tissue structures, such as tendons, ligaments and internal organs. Only the surface of bones can be visualised with ultrasound, as sound waves cannot pass through bone (unlike radiography, where the internal structure of bone can be evaluated).

There is a wide range of ultrasound machines available to the modern veterinary surgeon. These range from small, portable machines of the type that are commonly used in practice, for scanning tendons and fertility work; to larger, non-portable machines which produce a more detailed picture and have more functions (e.g. doppler flow ultrasonography), allowing more detailed examination of structures and organs.

(Above) Ultrasound of the leg of a horse showing the tendon structure (Left) Ultrasound machines in veterinary hospitals can now rival those available for human use