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 patient 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 body 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 visualized with ultrasound, as sound waves cannot pass through bone (unlike radiography, where the internal structure of bone can be evaluated).
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Ultrasonography.
