Ultrasound (also termed sonography, ultrasonography, and Doppler study) is a non-invasive diagnostic medical technique that uses high frequency sound waves to produce images (sonogram) of the internal structures of the body. These sound waves are not detectable by human hearing.
Using an ultrasound machine (ultrasonography), a technician or doctor moves a device called a transducer (probe) over part of your body. The transducer emits sound waves which bounce off the internal tissues, and creates images from the waves that bounce back. Different densities of tissues, fluid, and air inside the body produce different images that can be interpreted by a physician, typically a radiologist (a physician who specializes in imaging technologies). Many studies are done by a trained technologist (sonographer) and then interpreted by a radiologist.
A two-dimensional (2D) is the most common type of ultrasound exam. These 3D and 4D ultrasounds are possible due to the advances in computerized analysis of sound waves at different angles. Three dimensional images are compiled from the sound waves coming back at different angles and the images are easier to understand and show more details. The difference between a 3D and 4D ultrasound is that the 4D is like a video showing motion of a 3 dimensional object.
Ultrasound can be used as a diagnostic or screening tool to confirm medical disorders or to assist in performing medical procedures. It is also used as a therapeutic tool in treating musculoskeletal problems, renal stones (kidney stones), and gallstones.
Medically Reviewed by a Doctor on 2/11/2016
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