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Veterinary Ultrasound final


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What is attenuation?
loss of energy from an US pulse as it passes through tissue
What is acoustic impedence?
the ease by which a particular tissue transmits US vibrations - not all tissues are the same
What is boundary interface?
the junction/boundary between 2 tissues w/ different acoustic impedence
What is an acoustic window?
the straight path from the surface of the skin to organ of interest not blocked by bone, air, or mineral
What is a transducer footprint?
the size of the contact area between the transducer and the skin - size of footprint will affect choice of acoustic window
The ___ of the white dot on the screen is determined by how long it took for the echo to return to the transducer
The ___ of the white dot on the screen is determined by the intensity of the echo.
Describe how US works
transducer send US pulses into body, as US encounters various things portions of the US are reflected back to the tranducer - based on the strength and time of return of the US waves to the transducer, a picture is formed
Define reflection
enery lost from echoes that are reflected back to the transducer
Define refraction
energy lost from echoes that is scattered in other directions and never recd back by the transducer
Define hyperechoic
relatively bright area on the screen
Define hypoechoic
relatively dark area on the screen
Define isoechoic
areas of equal brightness on the screen
Define anechoic
black area on the screen - no echoes
Define echotexture
the overall appearance of a tissue or organ on the screen
Higher transducer frequency = ___ penetration & ___ resolution
decreased penetration
better resolution
Lower transducer frequency = ___ penetration & ___ resolution
increased penetration
poorer resolution
What kind of transducer has a large footprint, the crystals are in a straight line, & produces a rectangular picture
Linear array transducer
What kind of transducer has a small footprint, 1-2 crystals that travel back & forth in an arc, & produces a pie-shaped picture?
Sector transducer
What kind of transducer has a small footprint, the crystals are arranged in an arc, and produces a modified pie-shaped picture?
Curved (convex) array transducer
The transducer spends __% of its time producing sound pulse & __% of its time listening for echoes
1% producing, 99% listening for echoes
What is TGC and what does it do?
Time Gain Compensation - amplifies weaker deep echoes more than stronger close echoes, creates a more "even" image this way
What kind of picture does B mode produce?
Still picture
What kind of picture does Real Time mode produce?
a "moving" picture
Describe M mode - what is it used for?
moving parts depicted on scree as a series of undulating lines - used mainly for cardiac US
Define the term "US artifact"?
the production of an image on the screen which does not represent an acurate depiction of true anatomy
What is distal enhancement?
Brighter echoes on the distal side of fluid-filled objects - the beam does not lose as much energy travelling through fluid as it does through tissue
What is acoustic shadowing? What materials might cause this?
When beam strikes highly reflective interface (bone/air/stones), the beam is almost totally reflected, nothing left to travel deeper - produces a dark shadow distal to the object (hypoechoic area)
What is reverberation?
beam hits a highly reflective object at a perpendicular angles - the echo bounces of the transducer and hits the object again and again
What is refraction/edge shadowing?
beam is bent and deflected when it hits a curved object - and anechoic area develops distally to a curved edge
What objects produce edge shadowing?
kidneys, gall bladder, and fetal skull
What is a mirror image? What often produces this?
beam bounces between and object and a large, highly relective interface, producing two images - diaphragm often causes
What is beam width artifact?
although beam is vy thin, it does have some thickness - BW artifact is caused when beam slices through edge of two substances simultaneously - computer averages the image and it appears as though there is a mass
Direction that notch is pointing will always be on what side of the screen?
Notch points toward the patient's head in a ___ view
What side of the patient is the notch facing in a transverse view?
patient's RIGHT side
In a transverse view, the patient's __ side is shown on the ___ side of the screen
patient's right showing on left side of screen
In a sagital view of the kidney, where is the notch pointing?
toward the patient's head
In a transverse view of the kidney, where is the notch pointing
toward the patient's right side (operator's left side)
In a dorsal/coronal view of the kidney where is the tranducer and notch
notch toward patient's head, transducer alonf the side of the animal scanning in toward the spine
A vessel w/ white walls in the liver would be the what?
Hepatic Vein
Does the portal or hepatic vein have white walls?
The portal has white walls, the hepatic simply appears darker
In the kidney, which is darker, the cortex or the medulla?
What is the white substance often seen in the middle/renal sinus of the kidney?
What are the stomach "wrinkles" called?
What produces a "hostess cupcake" image when bisected?
small intestine

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