Ultrasound (copy)

• A sonometer was used to study sounds, Pythagoras used this to start sonography

• A sonar was introduced during the Titanic Era (1910s)

• Ultrasounds waves need some type of medium to travel

• Doppler- christian johann doppler, mid 1800s discovered

• Color flow doppler- detects bloodflow movement

• Spectral doppler- function that allows the showing of how blood flows through a vessel, can be combined with 2D and color scans

• frequency is measured in hertz*

• ultrasound is greater than 20,000 hertz

• transducers use PZT

• different tissue properties affect how sound travels through the body

• transducers are classified by frequency (2-18MHz = high, 1-3.5MHz = low)

• use high frequency for: breast, testicle, thyroid, ect.

• orientation marker on transducer- either towards head or right side

• ultrasound is the most operator dependant modality*

Terminology

• the echogenicity of a structure refers to types of echos/reflections it produces*

• anechoic = without any echos (black)*

• anything fluid filled is considered anechoic

• hypoechoic- appears dark drey, weak

• hyperechoic- a dense echo pattern from strong reflectors

• homogeneous= uniform structure throughout

• heterogeneous= non uniform, complex echo pattern that are a ,ixture of hypoechoic and hyperechoic

• description: cystic/anechoic-fluid and well defined, or solid- uniform or complex echoes

• shadowing and enhancement: shadowing is shadows, enhancement happens with a cystic structure

• AAA is abdominal aortic aneurysm