Week 4.1 Diagnostic Ultrasound Flashcards
(32 cards)
US imaging uses frequency of
over 20,000 Hz
what are the two categories of US imaging
therapeutic (heating for treatment)
Diagnostic (imaging)
what are the 3 challenges to sonography
image generation
image recognition
image interpretation
expand on the limitation of image generation
the principles of sound wave generation and the effects of tissue density makes it hard to get an image, and poor quality.
expand on the limitation of image recognition
planes of view and anatomy are hard to tell from US imaging
How is a sound wave propagated
the sound waves are absorbed, reflected, scattered and then attenuated (returned to the sound head)
how is the penetration and resolution of of a high frequency sonography
poor penetration but high resolution
how is the penetration and resolution of of a low frequency sonography
poor resolution and high penetration
what does anechoic mean
structures without internal reflectors, so no echo are returned. This is seen as black, like fluid
what is hypo-echoic
low level echo, that look grey, like muscles, synovial tissues, peripheral nerves
what is hyper-echoic
high level echo, like bright white and grey, meaning bone, tendons and fascia
which presents a greater risk, therapeutic or diagnostic imaging
therapeutic, because there is higher intensity, and higher risk associated with heating the tissues
TF: there are no biological effects on patients caused by exposure to present diagnostic US
true
what are the benefits of diagnostic US
inexpensive, non-invasive, safe, real-time, in office, bilateral examination and dynamic examination
what are the drawbacks of diagnostic US
operator dependent and
availability
how is diagnostic US prudent use with pregnancy
ALARA principle (As low as reasonably available) and informed consent, less than 5 minutes
what about prudent use with gaseous cavities
avoid direct, long exposure to lung tissue, and do not use individuals that have recently had a contrast medium injected
what do you use a 2-5 MHz curved (sector) array
abdominal wall, multifidus, bladder images,diaphragm
what do you use a 5-10 MHz linear array
TrA, Multifidus, diaphragm
why would you use a curvilinear probe
transducer elements, sector footprints, wider far-field view. more width and depth
why would you use a linear probe
transducer elements, rectangular footprint and wider near field of view
which would you use for deeper structures, curved or linear,
curved
the marker on the side of the image represents what direction
towards the examiner or the cranial direction
low frequency reaches ___ whereas high frequency is ____
deep, superficial
