Conrtast enhanced u/s (CEUS) Flashcards
(27 cards)
what is ultrasound contrast agents?
- gas liquid sispensions of biocompatible gas-filled microshpheres
- wjem injected they flow inimpedid through the patients circulatory system, mimicking the flow patterns of RBC’s while producing enhanced u/s reflectivity
what are contrast agents composed of?
- gassfilled microbubbles surrounded by an outter shell composed of phospholipids or sunthetic polymers
microbubbles are smaller than RBC’s T or F?
true
where are contranst agents injected?
- into patients arm
- remain in the blood vessels, not excreted
function of contrast agent- mircrobubbles?
- mircobubbles oscillate within the circulation in response to the changes within the u/s beam, compressing and expanding
- as bubbles oscillate they produce non-linear frequencies and a strong signal
the microbubbles oscillate at the same frequency and produce scattering at the same frequency at what MI?
- very low MI (<0.1)
what occurs at an MI 0.1-0.3?
the oscillations are no loner synchronized with the applied U/S beam and scattering with harmonic frequencies ensues (non-linear response)
what occurs at a high MI (0.3-0.6)?
- causes microbubbles to burst and the released gas rapidly diffuses into the surrounfing liquid
how long does an agent dose typically last?
4-6 mins
dose of contrast agent?
typically 0.1-0.3ml
contrast agents 1st generation?
- air-based- provide unstable during lung passage
1st generation contrast agent brand names? (2)
- echovist (no longer used)
- levovist (no longer used)
contranst agents 2nd generation brand names (4)?
- sonovue
- definity
- optison
- lumason
CEUS- equipment?
- all u/s machines have contrast specific software used to display the harmonic bubble signals
- contrast preset is set to enhance the image with the use of contrast agents not the organ itself
CEUS image optimization?
- Low MI
- dual screen utilized (1 2-d, one image black)
- focus zone placed at posterior part of image (bubbles tend to burst here)
- use of timer
- shallow breathing
- store cine clips during procedure
CEUS is used to enhance imaging of what organs and vessels?
- abdominal
- small parts
- vascular
- cardiac
CEUS wash in phase?
- early phase of injection, entry of agent into the plane of imaging
CEUS wash out phase?
- late phase of injection, exit of agent from the plane of imaging
CEUS 3 liver phases?
- arterial phase- earliest phase
- portal venous phase- early phase
- sinusoidal phase- late phase
timing of phases (start and end)?
- liver arterial
- liver portal venous
- liver late
- kidney cortical
- kidney medullary
- soft tissue arterial
- soft tissue venous
CEUS benign characteristics?
- lesions will remain enhanced in late phase
- stays echogenic from early phase to late phase
CEUS maliganant characteristics?
- fast wash in and fast wash out of contrast
- lesions will wash out in late phase, going from echogenic lesion in early phase to hypoechouc in late phase
- irregular vessel pattern
CEUS on vessles?
- delineates liminal perfusion
- reveals irregularities
- accurtate measurement of degree of stenosis
- length of stenosis
- neo-vascultariry visualization
- stent graft
CEUS steps of procedure?
- obtain consent
- start IV (canulla 20G or larger)
- preprocedural images
- mark skin
- switch to contrast preset
- activate contrast agent
- inject and saline flush
- start timer
- store cine clips
- end study
- store representitive still images and measurements from cine clips after exam
- iv removal, dressing
- patient post procedural instructions
