Doppler sonography
If you want to obtain even more information (for example, about flow speeds, directions or flow strengths), there are special procedures based on the Doppler effect: Doppler and color Doppler sonography. The Doppler effect is caused by the fact that the transmitter and receiver of a certain wave move relative to each other. So if you record the echo reflected by a red blood cell, you can use a certain formula to calculate how fast this particle moves in contrast to the stationary transducer that emitted the signal. Even more meaningful is the color-coded Doppler sonography, in which the color red normally stands for movement towards the transducer, blue for movement away from the transducer and green for turbulence.
Various organs
Depending on their nature, there are some tissues that can be visualized particularly well with the help of ultrasound, others that can hardly be visualized at all.Tissues that contain air (such as lungs, trachea or the gastrointestinal tract) or are covered by hard tissue (such as bones or the brain) are generally difficult to visualize. On the other hand, ultrasound provides good results in soft or fluid structures such as the heart, liver and gallbladder, kidneys, spleen, urinary bladder, testicles, thyroid and uterus (including the unborn child if necessary). Ultrasound of the heart (cardiac ultrasound, echocardiography) is used particularly frequently to examine vessels for possible constrictions or occlusions, to monitor pregnancy, to examine the female breast (as a complement to palpation and mammography), to detect tumors, cysts or organ enlargements or -or in order to be able to visualize organs, vessels and lymph nodes of the abdomen and to recognize possibly existing tumors, stones (for example gallstones) or cysts.
Other applications
However, ultrasound is not only used in medicine, but is also applied in many other areas of everyday life. Not so long ago, for example, ultrasound was used to transmit information in remote controls, among other things. In addition, ultrasound can be used to practically “scan” certain materials, which can be used, for example, with sonar to scan the seabed or with ultrasonic testing equipment that can detect cracks or inclusions in some materials.
