Chapter 12: Duplex Ultrasound of Lower Extremity Arteries Flashcards
A localized dilation of an artery involving all three layers of the arterial wall
aneurysm
A radiologic imaging technique performed using ionizing radiation and intravascular contrast material to provide detailed arterial system configuration and pathology information
contrast arteriography
ultrasound imaging of the arterial system performed to identify atherosclerotic disease and other arterial pathology and establish a detailed map of the arterial system evaluated
duplex arteriography
the deposit of fatty material within the vessel walls, which is characteristic of atherosclerosis
plaque
Normal lower extremity arterial finding
walls smooth and uniform
no focal areas of increased PSV
slight change in PSV across segments of arterial tree
multiphasic waveform with reverse flow component
uniform color filling
Stenotic lower extremity arterial finding
wall thickening
calcification
plaque encroaching into vessel lumen
focal increase in PSV
Poststenotic turbulence
Vr > or equal to 2.0
Monophasic waveform distally with no reverse flow and continuous flow in diastole
focal area of aliasing
turbulence distally
Aneurysm lower extremity arterial finding
increased diameter 1.5 times larger than adjacent more proximal segments
turbulence within dilated area
no color filling
gold standard imaging tool to evaluate peripheral arterial system; associated with systemic and local complications
contrast arteriography
indications of acute arterial ischemia
pallor
pulselessness
paralysis
parasthesia
intense pain
pulsatile mass detected in femoral or popliteal regions
peripheral arterial aneurysms
Primary pathologies suspected for arteriography
atherosclerotic
aneurysmal diseases
The SFA passes through the ______ and then becomes the popliteal artery.
adductor canal (Hunter’s canal)
The anterior tibial artery branches off the _____ artery.
popliteal
slightly smaller in diameter than the popliteal artery
3-5 cm longer
tibioperoneal trunk
The tibioperoneal trunk bifurcates into the _____ and _____.
peroneal artery
posterior tibial artery
Primary tool to categorize disease
velocity spectra
Velocity ratio calculation
PSV at stenosis divided by PSV just proximal to stenosis
used to estimate degree of stenosis
velocity spectra
______ can detect flows as low as ____.
2 cm/s
Most common problem with duplex arteriography
arterial wall calcification
Calcifications produce ______.
acoustic shadowing
Most plaque will appear ______.
heterogeneous
Irregulary surfaced plaques may represent _____ lesions.
ulcerative
A vessel is diagnosed as aneurysmal if the diameter is ____ times greater than the adjacent more proximal segment.
1.5
What will color flow imaging look like in areas of disease?
color aliasing
color flow channel within lumen reduced
color bruit may be present in surrounding tissue
primary measurement for severity of stenosis
PSV
A PSV Vr of ____ indicates a stenosis 50% or greater.
2-2.5
A PSV Vr of _____ indicates a stenosis 70% or greater.
3-3.5
normal or mildly diseased
> 50%
moderately diseased
50-69%
severely diseased
70-99%
high resistance, multiphasic waveform; sharp upstroke to peak systole maintained
normal peripheral arterial bed
vessel distal to disease will display a low-resistance signal with antegrade flow through diastole; delayed rise time to peak systole
significant arterial disease or occlusion
waveforms can display very high resistance pattern with only an antegrade flow component during systole and no flow during diastole
vessels proximal to occlusion or near occlusion
Used when DA not able to provide adequate imaging
standard percutaneous preoperative CA
_____ can identify arterial segments, while ___ cannot.
duplex arteriography
contrast arteriography
________ can be efficiently used for evaluation of the lower extremity arteries and is particularly helpful in patients being evaluated for lower extremity revasculartization.
Duplex ultrasound
What is the main technical limitation in the routine use of duplex ultrasound instead of contrast angiography to visualize arteries of the lower extremities due to?
most plaque will be calcified
On a posterior approach of the popliteal fossa, what is the branch identified on the anterior aspect of the image in relation to the popliteal artery?
gastrocneumius artery
Which artery is best visualized by a posterolateral approach at the level of the calf?
a. the posterior tibial artery
b. the peroneal artery
c. the popliteal artery
d. the tibioperoneal trunk
b
Which method represents good practice to thoroughly evaluate arterial disease in the lower extremities when using B-mode to view the vessel?
a. viewing in sagittal only
b. viewing in transverse only
c. moving from medial to lateral
d. using both transverse and longitudinal planes
d
What is the primary tool to evaluate disease of the lower extremity arteries using duplex ultrasound (with the exception of aneurysm)?
peak systolic velocity
How is the velocity ratio calculated?
PSV at stenosis divided by PSV proximal to stenosis
Which of the following is NOT a consideration when assessing the possibility of treatment of an arterial lesion by angioplasty or stenting (or both)?
a. size of the artery
b. position of the branches
c. length of the stenosis
d. location of the stenosis
b
Why does duplex ultrasound have an advantage over contrast angiography for the examination of vessel walls?
the wall thickness can be measured
Which of the following is the main pitfall of duplex ultrasound (in general) in examining arterial disease?
a. flow at velocities less than 20 cm/s
b. flow at velocities over 400 cm/s
c. length of occluded segment
d. collateral vessels
a
When using duplex ultrasound to record slow flow (<20 cm/s) in an arterial segment, which of the following adjustments would NOT be useful?
a. decrease the PRF
b. use a low wall filter
c. increase the persistence of color
d. decrease the Doppler gain
d
When assessing the appearance of a plaque on a grayscale image, what might an irregular plaque surface indicate?
an area of ulceration
Why is reporting the presence of a partial thrombus in an aneurysm important?
pieces of thrombus can embolize
When can a greater than 70% stenosis in any arteries of the lower extremities be safely inferred?
The Vr is equal to or greater than 3.
How is low-resistance blood flow characterized on a Doppler spectrum?
antegrade flow throughout diastole
Which of the following is NOT a potential pathologic finding when the Doppler spectrum of an artery of the lower extremity displays low-resistance characteristics?
a. arteriovenous fistula
b. postreactive hyperemia
c. cellulitis
d. trauma
b
Doppler spectra with a characteristic low-resistance outline may be seen distal to a hemodynamically significant stenosis. What will the Doppler spectra also display?
delay on the upstroke in systole
What characteristic will Doppler spectra in an arterial segment proximal to a hemodynamically significant stenosis or an occlusion have?
no flow in diastole
Which of the following is NOT a factor typically associated with the need to perform contrast angiography after a limited duplex ultrasound of the arterial system?
female gender
Why is the use of contrast angiography in diabetic patients particularly worrisome?
nephrotoxic agents
What aspects of duplex ultrasound assessment of the lower extremity arteries allow better estimation of the true hemodynamic significance of an arterial lesion when compared to contrast angiography?
Doppler spectrum analysis and color Doppler
Conditions and risk factors for which patients are referred for duplex ultrasound of the lower extremity arteries are ______ as those for indirect physiologic testing.
the same
The below-knee segment of the popliteal artery is best examined through a _____ approach.
posterior
Most arteries of the lower extremity can be examined by duplex ultrasound using a _____ approach.
medial
The two arteries or arterial segments, which cannot be well examined with duplex ultrasound via a medial approach, are the popliteal artery and _______.
anterior tibial artery
The superficial femoral artery typically changes name to become the popliteal artery as the vessel exits the ______.
Hunter/adductor canal
On a posterior approach of the upper calf, the artery branching off the popliteal artery deep to the popliteal artery is most likely the ______.
anterior tibial artery
In general, color and power Doppler’s primary advantage is for _____ and tracking of the vessels.
localization
When an occlusion is discovered during duplex assessment of the lower extremity arteries, documentation of where the vessel is _______ by collateral flow is useful to the vascular surgeon.
reconstituted
To evaluate the dorsal pedis and distal posterior tibial arteries adequately, a sonographer should be particularly careful with the ______ from the transducer.
pressure
Duplex ultrasound is superior to contrast angiography in determining a suitable site for the distal anastamosis of a graft because it can detect the _____ area of the vessel.
softest
Using a lower frequency transducer to view the SFA at the adductor canal or the tibioperoneal trunk at the upper calf will reduce ______.
resolution
Determining/characterizing the “nature” of a plaque or wall thickening is important information a sonographer can convey to a surgeon because ______ through a calcified plaque is almost impossible.
suturing
Although the peak systolic velocity (PSV) is the primary measurement obtained, stenoses are classified based on ______.
velocity ratio
Using duplex ultrasound instead of contrast angiography in patients with severe-to-critical limb ischemia is recommended because the examination with duplex is more _____.
expeditious
A vessel is considered aneurysmal if the diameter is ____ times greater than the more proximal segment.
1.5
Very low flow, particularly to assess the patency of possible outflow vessels, is more easily achieved with duplex ultrasound than with contrast angiography with the use of _____.
power
When assessing the lower extremity arterial system with duplex ultrasound, only the first few centimeters of the _______ artery are evaluated.
profunda femoris
Distal to a hemodynamically significant stenosis, the Doppler waveform demonstrates poststenotic _______.
turbulence
At a measured diameter of 1.1 cm, a common femoral artery would be considered ____ whereas a popliteal artery that measures 1.1 cm would be considered ______.
normal
aneurysmal
As compared to contrast arteriography, duplex ultrasound allows direct visualization of the entire artery and not just the _____.
lumen
A patient with chronic arterial ischemia will have the following symptoms except:
a. hair loss
b. paralysis
c. nail thickening
d. skin changes
b
Examination at the femoral, popliteal, and tibial vessels generally is best performed using:
a linear array transducer with imaging frequences between 4 and 7 MHz
Which statement correctly describes the standard approach to scanning the deep femoral or profunda femoral artery?
a. The PFA is followed to the adductor canal
b. The PFA is not routinely included in the lower extremity protocol
c. only the first few centimeters of the PFA is scanned
d. The PFA is followed through the entire length of the thigh
c
The use of color during arterial ultrasound examinations can do all of the following except:
a. rapidly assess flow dynamics
b. guide the placement of the Doppler sample volume in the area of the greatest velocity shift
c. assist with tracking the course of a vessel
d. determine the percent of stenosis
d
During an ultrasound examination, the following velocities are obtained: proximal to a stenosis PSV = 98, at the stenosis PSV = 233, distal to the stenosis = 76. What is the correct velocity ratio for this stenosis?
233/98=2.4
In addition to assessing the degree of narrowing, which of the following is the least helpful prior to angioplasty and/or stent placement?
a. vessel depth
b. length of stenosis
c. plaque characteristics
d. artery size
vessel depth
Methods that can be employed to overcome the technical challenges of vessel calcification include all of the following except:
a. using multiple insonation planes
b. using multiple insonation planes increasing persistence
c. increasing pulse repetition frequency
d. increasing power Doppler gain
c
Which feature should be closely examined to aid in assessing the age of an occlusion?
the adjacent vessel walls
The presence of which of the following most increases the embolic risk or an aneurysm?
a. size of the aneurysm
b. calcification in the aneurysm walls
c. thrombus within the aneurysm
d. length of the aneurysm
c
All of the following are associated with a stenosis except:
a. color aliasing
b. the color flow channel will be reduced
c. the color will appear uniform
d. a color bruit may be present
c
Normal lower extremity arterial waveforms have all of the characteristics except:
a. a sharp acceleration to peak systole
b. an early systolic peak slightly before the highest peak velocity
c. a reflected wave displayed as retrograde flow in early diastole
d. a rapid deceleration
b
Continuous, antegrade flow through diastole in a peripheral artery can normally observed proximal to:
an arteriovenous fistula
Which of the following is not an advantage of duplex ultrasound over contrast angiography?
a. allows for plaque characterization
b. waveform analysis provides a better estimation of hemodynamic significance of a stenosis
c. provides better visualization of collateral network
d. can detect flow in very low-flow states
c
What waveform type presents proximal to an occlusion or near occlusion?
a high resistance pattern with only antegrade flow during systole and no flow during diastole
The majority of the anterior tibial artery can be followed using what approach?
anterolateral
Signs and symptoms of chronic arterial insufficiency
intermittent claudication
rest pain
nonhealing ulcers; gangrene
trophic changes (hair loss, nail thickening, skin changes)
Signs and symptoms of acute arterial insufficiency
pallor
pulselessness
paralysis
paresthesia
intense pain
coolness
Vessels to be examined during a lower extremity duplex ultrasound:
CFA
SFA
PFA
Popliteal artery
PTA
ATA
Peroneal artery
_______ is used as a primary tool to categorize disease
Spectral Doppler
Normal arterial walls are:
smooth and uniform
Atherosclerotic plaquing can be described as:
homogeneous or heterogeneous
smooth or irregular
Calcifications may be present in arteries, creating ______
acoustic shadowing
Aneurysm is present if the diameter of a vessel is ____ times greater than the adjacent, more proximal segment.
1.5
External Iliac PSV
119 =/- 22
Common femoral PSV
114 +/- 25
Superficial femoral (proximal) PSV
91 +/- 14
Superficial femoral (distal) PSV
94 +/- 14
Popliteal PSV
69 +/- 14
PSV velocity ratio less than or greater to 2 =
50% stenosis
PSV velocity ratio less than or greater to 3 =
70% stenosis
Considered the gold standard for diagnosis or arterial stenosis
Contrast Arteriography
