RAD-US Flashcards
What are advantages of an US?
-portable -easy -can do immediately at the bedside -interpret real-time (POCUS) -no radiation -can scan almost anything -low cost -can be taught to anyone!
What are the disadvantages of other imaging modalities (MRI/Ct/X-ray)?
-usually have to move patient -radiation -time consuming -need radiologist to help interpret many -expensive -obesity can be a barrier -may have to give contrast
What are the disadvantages of an US?
-less detailed -can miss things -operator error
What are the advantages of other imaging modalities?
-higher level of detail -less dependent on human error -choice for brain/neuro pathology
How do US work?
Ultrasound probe sends and receives sound waves - the object will transmit waves depending on its density that will bounce back and show a picture based on the sound waves
What does hyperechoic mean?
-tissue reflects -ULS waves appear bright
What things will appear hyperechoic?
-bones -stones -muscle (not super bright) -liver/kidney
What does hypoechoic mean?
-tissue absorbs ULS waves and not a lot is getting reflected back -will appear dark
What things appear hypoechoic?
-blood -fluid
What does isoechoic mean?
same echogenicity as surrounding structures
What does anechoic mean?
-No intermal echos -dark w/ no activity
What is shadowing?
-an object is so reflected that below that there is less activity casting a shadow -this is very common with stones
Does air reflect or absorb US waves?
Neither! It’s the enemy on US
Turning the gain up does what?
It makes the picture brighter so, turning it down makes it darker
What are the kinds of probes we use?
- linear 2. phased array (aka: cardiac) 3. curvilinear 4. endocavitary
Describe the linear probe and what we use it for.
-high frequency = can see better detail but over very small area -used for: skin/soft tissue, blood vessels, most procedures and eye -beams do not go very deep
Describe the phased array probe and what we use it for.
-small face but fans out into larger region -great for getting in between ribs into intercostal spaces (bone causes lots of artifact and can impair image) -best for echo -called the cardiac probe
Describe the curvilinear probe and what we use it for.
-low frequency - poor detail -large, wide face helps with scanning large areas -great for abdominal exam
Describe the endocavitary probe and what we use it for.
-intraoral - looking for peritonsillar abscess -vaginal ultrasound to look at ovaries/uterus
What if a FAST exam?
-focused assessment with sonography in trauma -looking for “free fluid” (blood) in RUQ, LUQ, suprapubic region, orvpericardium -can be expanded to look for hemothorax/pneumothorax as well
What probe do we use for a FAST exam?
-curvilinear probe b/c of the large surface area -doesn’t give a lot of detail, but we can easily identify free fluid/blood
What are the goals of a FAST exam?
-rapidly identify source of hypotension in trauma patient: free-fluid in the abdomen including hemorrhage -check 3 places where blood loss can happen (abdomen, pericardium, and lung) -in hypotensive patient, don’t need to wait for ct > go directly to OR -can decide to put in chest tube immediately -WAY less invasive than DPL (diagnostic peritoneal lavage)
What is a DPL?
-diagnositc peritoneal lavage -put fluid into the abdomen and draw it back out to see if blood comes back -we don’t want to do this if we can avoid it, because we’re violating the peritoneum
What are views of the bedside echo?
-parasternal long axis -parasternal short axis -subxiphoid -apical 4 chamber **not the same as a detailed cardiology echo
What probe do we use for a bedside echo?
phased array probe! b/c the small face can be fit between rib spaces
What are the goals of a bedside echo?
- Is there a pericardial effusion? 2. Is the LV function normal or depressed? 3. Is chamber size normal or abnormal?
What’s the probe placement of a parasternal long axis view?
-the probe is placed just left of the sternal border with the marker facing the patient’s right shoulder
What’s the probe placement of a parasternal short axis?
-from the PLAX rotate the probe by 90 degrees towards the patient’s right hip to obtain the short axis view
What’s the probe placements for a subxiphoid view?
place the probe at a flat angle just below the xiphoid process
What’s the probe placement for an apical 4 chamber view?
slide the probe towards the PMI and flatten the angle
When’s the only time you will really see the lung?
If it’s floating in fluid!!
If we are doing a lung US, when would we use the curvilinear probe?
we’d use it to look at the pleural spaces between ribs
Are A lines normal or abnormal?
Normal!!
Are B lines normal or abnormal?
Abnormal! Associated with HF
How can we assess a pneumothorax with US?
-use a linear probe -look for normal lung sliding
What probe do we use for a gallbladder US?
curvilinear probe
How do we perform a gallbladder US?
-left lateral decubitus -identify the fundus, neck and common bile duct -stones are hyperechoic with shadowing
What are some s/sx of cholecystitis?
-fluid around the gallbladder -murphy’s sign -stone -shadowing
What probe do we use for a kidney US?
Curvilinear probe
How do we perform a kidney US?
-fast view orientation in RUQ/LUQ -look for dilation of the collecting system (hydronephrosis)
What kind of probe do we use to a DVT US?
linear probe
How do we do a DVT US?
-we look at the femoral vessels and the popliteal vessel -compress the veins with the probe -veins will not collapse in the presence of the DVT
What probe do we use for an abdominal aorta US?
curvilinear probe
How do we perform an abdominal aorta US?
-start in transverse view over epigastrium -follow aorta down to iliac bifurcation -should be no wider than 3 cm
