Ultrasonography and viewing techniques Flashcards
what kind of beam is received by the ultrasound probe and converted into an image
reflected beams
time taken for the echo to return gives depth and location to the structure is called what
interface
the loudness of the returning echo gives the brightness on the screen is called what
amplitude
sector transducer
- mechanical crystal movement
- commonly used for echocardiography, intrathoracic and intrabdominal organs, regions with small contact area etc.
- disadvantages: reduced near field resolution, diverging far field, must be warmed up before use
phased array
- commonly used for echocardiography, thoracic structures, abdominal organs, regions with small contact area
- disadvantage: reduced near field resolution
linear array
- commonly used to view abdominal organs, muscles, joints and tendons
- disadvantages: large contact areas, limited field of view
curvilinear array
- commonly used for abdominal organs and preg dx
microconvex
- best for generic use
Best multiuse
what is the effect on the US image if you use low frequency
high depth, low resolution
what is the effect of using a high frequency on an US image
poor depth, high resolution
what is the ideal frequency fo producing a good US
highest frequency possible to reach desired depth
high frequency=high structure (top of skin)
what is the effect of gain on an US
- the amplification applied to the returning echo
- compensates for the sound being quieter when it has to travel farther to return
- turned up for depper tissues (time gain compensation)
what is the standard viewing position for a lateral view
- head/cranial end should be to viewers left
- dorsal aspect should be on top
what is the standard viewing orientation for ventrodorsal/dorsoventral views
- cranial aspect at top
- left side should be on right side of image
what os the standard viewing orientation for mediolateral/lateromedial views of the limbs
- proximal aspect at top
- cranial aspect to the left
what is the standard viewing orientation for craniocaudal/caudocranial views of the limbs
- proximal aspect to the top
- no convention whether medial or laterla aspect be left or right
what is the standard vieing position for ultrasound imaging
- cranial and right hand side should be to viewers left
some echocardio views will differ
what does the term radiolucent refer to
few of the x-rays are absorbed, most pass through to image receptor
ex: gas appaears black
what does the term radiopaque refer to
- most of the x-rays are absorbed and very few penetrate through to the image receptor
- ex: dense tissues like bone or metal appear white
what does the term soft tissue opacity refer to
soft tissues and fluid have the same radiographic opacity and are described as soft tissue opaque
ex: organs, soft tissues appear grey
What does the term anechoic refer to
- structure produces no echo
- sound passes through and is not reflected
- ex: fluids appear black
what does the term hypoechoic refer to
- structures that produce little echo
- most sound passes through and is not reflected
- ex: tissues with highh water content appear dark grey
what does the term medium echogenicity refer to
- structures produce a medium echo
- medium amount of sound passes through and is reflected
- ex: soft tissues (liver, spleen) appear medium/light grey
what does the term hyperechoic refer to
- little sound passes through and most is reflected to the transducer
- ex: gas, bone, mineralized tissue and DCT appear white
