PA Anatomy: Imaging Overview- US

Ultrasound uses reflection or absorption of sound waves by body tissues to generate an image; very high frequency sound is sent into the body from an object called a 'transducer', which can also receive reflected sound and determine the depth within tissue where the beam was reflected; ultrasound is blocked by air and bone; use of higher frequency sound gives better detail but poorer penetration of deep tissues; because the transducer is held by an operator, the image quality varies considerably with the skill of the operator ('operator-dependent'); actual motion of objects can be viewed in 'real-time' and captured as video

1) recognize each type of imaging and physical property--a section or slice of the body, with variable shape depending on the type of transducer being used; images will look grainer than other types of imaging; physical property is sound reflection or absorption

2) radiation--uses NO ionizing radiation, very high frequency sound can slightly heat body tissues but usually not enough to be felt

3) technical factors are mostly related to the transducer being used, which will determine width and depth of the field of view, as well as the imaging plane, which will be determined by how the transducer is held up to the body

4) WHITE areas are called 'echogenic' or 'bright' and BLACK areas are called 'anechoic','echo lucent' or 'low echogenicity'

5) types of disease that are best displayed: superficial structures (like some blood vessels, thyroid gland, testes, tendons and ligaments), acute diseases (study can be done quickly and portably), organs that do not contain gas, heart, fetus, female genital tract

6) types of disease that are not well demonstrated: lungs, bones, very deep organs, organs overlaid by gas (pancreas, in many cases)