Mri Scan Of Knee Joint

Radiofrequency source, which emits radio waves

Ultrasound scanning

In ultrasound scanning, images are created using ultrasound waves (high-frequency, inaudible sound waves). A device called a transducer is moved over the skin or, in some cases, inserted into a body opening such as the vagina or rectum, and sends ultrasound waves into the body. Where tissues of different densities meet, or where tissue meets fluid, the waves are reflected; the transducer picks up the echoes and passes them to a computer, which creates an image on a monitor. The images are updated continually so that movement can be seen. Doctors often use ultrasound to look at fetuses in the uterus (see Ultrasound scanning in pregnancy, p.280) or the walls and valves of the heart, or to detect abnormalities such as cysts and kidney stones. A technique called Doppler ultrasound scanning (p.235), which shows the direction and speed of blood flow, is used to detect problems such as narrowed arteries or clots in veins.

51 Tips for Dealing with Kidney Stones

51 Tips for Dealing with Kidney Stones

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