test 2 Flashcards
Pressure waves are sent through body and echo waves return to the transducer elements and are processed to create ultrasound images
ultrasound
the major source of sound wave attenuation is soft tissue (the conversion of energy to heat)
absorption
occurs when sound waves encounter a boundary between two different media.
reflection
when waves are reflected off of bone an ____ _____ will be created
acoustic shadow
when us waves encounter a medium with non-homogenous surface
scatter
the consequence of scatter is
speckle
why is gel used in ultrasound
ensures proper contact between transducer and patient, for sound to travel through tissues
frequency (Hz) of the wave is measured in
cycles per second
Ultrasound imaging frequency
1-20 MHz
what frequency is better for deeper structures
lower frequency waves
frequency that provides better resolution for shallow structures
high frequency waves
Ultrasound gets _____ in tissue, signals get ____ in deeper structures, resulting in _____images.
Ultrasound gets attenuated in tissue, signals get weaker in deeper structures, resulting in darker images
_______ may prevent imaging behind solid structures
absorptions
_________may prevent imaging behind solid structures or air
Hard reflections
ultrasound transducer that provides a wide, near field image
Curved Array
when scanning for fetus or abd what type of transducer would you use
Curved array
pie shaped image, quality not as good as curved array.
phased array
what type of transducer would be better for ultrasounding the heart behind ribs
Phased array
transducer that gives the best resolution, used in vascular and superficial soft tissue studies
linear array
runs parallel to the ground separating superior from inferior
transverse plane
oriented perpendicular to ground separating pt left from right
Sagittal/longitudinal plane
separates the pt anterior from posterior
coronal plane
used to image structures that don’t line up with the other planes
Oblique plane
commonly used mode in ultrasound, different shades of gray in a 2 dimensional picture
B mode