ultrasonography Flashcards
how does ultrasounds produce images?
uses high frequency sound waves to produce an image of internal body structures
what are sound waves?
mechanical ausillations in pressure transmitted through a medium
what are the three frequencies of sound waves?
infrasound, acoustic, ultrasound
ultrasound evolved from
SONAR
explain the process of an ultra sounds
ultrasound pulse is created
sound travels till it hits a reflective surface
bounces back as an echo
the tranducer keeps track of time from the beggining of the pulse to the time it is recieved, why is this important?
the length of time it takes is proportional to the distance the pulse travels into the body before it is reflected
define acoustic properties/echogenicity
how the tissues reflect the sounds
define anechoic:
few to no echoes
define hypoechoic:
few echos
define hyperechoic:
many echos
what does air do to an ultra sound?
scatters sound
what does liquid do to a ultrasound?
transmits sound with little attenuation leading to distant enhancement
what do bones/uroliths/metal do to sound?
reflect and cause acoustic shadowing
what creats the pulse in a transducer?
a piezoeltric crystal
the data collected by the transducer is stored in the computer and then what?
transmitted at 15-30 images per second to produce a real time image
what are the four types of probes?
high frequency
low frequency
linear probes
curvlinear (convex) sector probes
what probe is 5-7.5 mhz?
high frequency
what probe is 2.5-3mhz?
low frequency
what are three characteristics of the high frequency probe?
most common in small animals
good resolution and detail
limited depth of penetration
what are teo characteristics of low frequency probes?
used in lg animals
greater depth of penetration but poorer detail
what are two characteristics of the linear probe?
produce rectangle shaped images
used for high resolution scanning of abdomen and equine reproductive tract
what are three charcteristics about the curved convex sector?
produce pie shaped image
most common
used in small animals including heart
where should the reference mark be on the tranducer?
2
oriented cranially when in the saggital plane and to the Right side of the animals body if scanning in the transverse plane
when doing a cystocentesis with an ultra sound should you use ultrasound gel or diluted alcohol
diluted alchohol 50:50
what are six reasons for ultrasounds?
abdominal reproductive extremities eyes echocardiograpghy doppler
how long should the patient be fasted for an abdominal ultrasound?
12 hours
where is the hair clipped and scrubbed for an abdominal ultrasound?
caudel aspect of ribcage to pevic brim
what are two positions for abdominal ultrasounds?
V/d or lateral recumbency
when is the optimum times for pregnancy detection in dogs and horses?
dogs 30 days
horses 11 days
what are three types of abnormalities that we could see in a reproductive ultrasound?
pyometra, cysts, endometriitis
where are extremity ultrasounds used?
in horse legs below the crapals and hoof
what does the ultrasound of extremities allow the diagnosis of? 3
tramatic injury
infection
inflammation
what are four things you are able to visualize in an echocardiography
valves
chamber sizes
wall thickness
blood flow via doppler
what does a long axis view show in an echocardiography
heart from base to apex in saggital plane
what does the short axis veiw show in an echocardiography
shows heart in the transverse plane
what is B-mode
produces 2d image, brightness seen corresponds to returning echos
what is m mode
1d view
shows traced display of movement of the heart chambers
used to measure chamber size and wall thickness
what is the doppler echocardiography used for?
to evaluate blood flow and allows measuer of blood flow velocity and direction in heart
what is a doppler echocardiography based on?
shift in frequency of returning echoes
