Duplex/Color flow venous imaging Flashcards
Sources for false positive?
- extrinsic compression: tumors, ascites, and pregnancy
- peripheral arterial disease: decreased venous filling
- chronic obstructive pulmonary disease: elevated central venous P
- improper Doppler angle or probe pressure
- superior vena cava syndrome
Sources of false negative studies?
prox obstruction
technically limited studies
May be difficult to thoroughly evaluate what peripheral veins in the lower extremity secondary to vessel size, depth, and course?
infra-popliteal
Difficult to thoroughly evaluate what peripheral upper extremity veins secondary to bony structures?
subclavian and brachiocephalic/innominate
What is the patient positioning for upper extremity peripheral vein?
supine or low fowlers position
arm in pledge position
What settings can be adjusted to maximize color filling and flow patterns?
- adjust color scale to detect slower velocities
- change wall filters
- increase color gains
What is another word for compressibility?
coaptation
What are the possible venous flow patterns?
spontaneous, phasic, augment with distal compression, augment with proximal release
Signal immediately heard at all sites except what vein?
posterior tibial
what is the lower extremity phasicity?
increase with expiration and decreases with inspiration
what is the upper extremity phasicity?
decreases with expiration and increases with inspiration
pulsatile venous flow pattern evident with fluid overload or what?
congestive heart failure
What is a technique to collapse the subclavian and innominate?
a quick breath through pursed lips should collapse vein
Flow reversal usually in response to a valsalva maneuver or during prox manual compression indicates what?
venous refulx
Reflux is identified when reversed flow last more than how long?
1 sec
Deep inspiration causes the abdominal and pelvic veins what?
dilate
Phasic, bi-directional/pulsatile Doppler signals are in what veins?
IVC, renal, and hepatic
minimally phasic, continuous Doppler signals are in what veins?
portal, splenic, and mesenteric
There is minimal flow fluctuation in the portal vein and flow is variable in the hepatic veins when?
during inspiration
If flow is not spontaneous at the CFV, FV, and/or Pop V what could be the cause?
obstruction distal to or at the site
If flow is not phasic, but rather continuous, what could be the result?
a proximal obstruction
Where might an obstruction be if the is no augmentation with distal compression seen?
obstruction may be between where you are compressing and where you are listening, or slightly more proximal
If there is no augmentation with proximal release, where might an obstruction be?
proximal
If flow increases during proximal compression, what does that signify?
venous reflux
A compressible vessel with evidence of rauleau formation on B-mode could be what?
normal or suggest proximal obstruction
What is the appearance of chronic clot?
- highly echogenic
- visible collateralization or recanalization may be evident
- vessel not dilated; may retract over time
Flow characteristics with chronic clot?
- abnormal Doppler venous signals may be evident, such as continuous, decreased phasicity, or no augmentation
- venous reflux lasting >1 sec
Where is an IVC interruption device usually placed?
below renal veins and may appear as bright echogenic lines
With systemic venous hypertension what is evident?
persistent dilated vessels
Increased portal venous pressure can result in what flow alterations?
- reversed flow in portal vein (hepato-fugal)
- collateral development
What is Budd-Chiari Syndrome?
- results from hepatic occlusion
- primary site of obstruction may be hepatic vein, sinusoids, or IVC
What are the clinical findings of Budd-Chiari Syndrome?
hepatomegaly, abdominal pain, sudden onset of ascites
