What is Ultrasonography?

Medical ultrasound ( ultrasound , ultrasound diagnostics ) is a medical imaging diagnostic technique based on ultrasound (ultrasound) that visualizes muscles and internal organs, including their size, structure, and pathological lesions. Obstetric ultrasound is widely used in prenatal diagnosis during pregnancy.

Ultrasound diagnostics does not have a long history. It was only used in the 20th century, but it has an irreplaceable role in current medical diagnostics. Ultrasound now

Generating an image from a sound wave goes through three steps:

Ultrasound uses a probe containing one or more transducers to emit pulses to an object. When the sound wave encounters objects with different acoustic impedance, part of the sound wave will be reflected, and when the probe detects it, it will be an echo. The time that the echo returns to the probe is measured and recorded to calculate the depth of the tissue interface that produced the echo. The greater the difference in acoustic impedance between the two substances, the stronger the echo. The difference in acoustic impedance between a liquid and a gas is so great that most of the acoustic energy encountered at its interface is reflected, making it impossible to visualize objects outside its area.

The speed of sound waves in different substances varies, depending on the substance's

Doppler ultrasound greatly improves the ability of medical ultrasound examination, it uses

• Correct

  • Ultrasound equipment pair

    There has been controversy over the safety of ultrasound. Since ultrasound is a form of energy, there is a question: "What effect does this energy wave have on my tissues?" There are reports that some women who have received more than the recommended number of ultrasound examinations produce low birth weight ^[3] .

    The FDA warns that laboratory studies have shown that diagnostic levels of ultrasound can have physical effects on tissues, such as mechanical shock and temperature rise. And it is recommended that the public should not be exposed to ultrasound unless necessary, especially pregnant women. Although there is no evidence that these physical effects can harm the fetus, the energy transmitted by the ultrasound examination must not be considered to be completely harmless to the fetus, and the FDA does not permit the use of medical ultrasound imaging equipment for non-medical purposes such as fetal photos, video commemorations, and medical Ultrasound imaging equipment is listed as prescription equipment.

    Some possible side effects:

    • Thermal effect: Local tissue absorbs the energy of ultrasound and raises the temperature of the tissue.

    • Cavitation effect: Dissolved gas is released from the solute due to local temperature rise.