Ultrasonography uses high frequency sound waves to create images.

In ultrasonography, sound waves are directed into the body, and the reflected sound waves are used to create an image. The reflected sound waves give information regarding the depth, type of tissue, and tissue interfaces. This information is converted into a grayscale image.

Unlike radiography, CT and fluoroscopy, ultrasound does not use ionizing radiation and thus is very safe. It is non-invasive, relatively inexpensive, and allows one to perform "real-time" or "live" imaging and to observe motion.

You can view individual sections of this module using the selections on the right, or click "next" to move sequentially through the module.

  Learning sections  
1. How images are obtained
2. Factors affecting appearance
3. What anatomical structures are well seen
4. Indications for use