Technique of Doppler of LLA Description: General Rules, Role and place of Real-Time Gray-Scale Imaging, Duplex Doppler Sonography, Color Doppler sonography and of Power Doppler sonography. Scanning Technique is described as well as Interpretation and Reporting.
Doppler of Lower Limb Arteries. Technical Aspects.
1. Edited on 2016 August 10.
Doppler of Lower Limb Arteries - Technical Aspects
Dr WALIF CHBEIR
No financial relationships with commercial entities to disclose.
Figures will be published in second time after obtaining copyright permission
* General Rules:
1-Explain the procedure to the patient and answer any questions.
2-Obtain and document applicable patient history, signs and symptoms as well as risk factors
on appropriate forms.
3-Verify that the procedure requested correlates with patient’s symptoms.
4- pertinent medical history: • Determine if the patient has a history of recent deep vein
thrombosis (ankle-brachial indices would not be performed in the presence of deep vein
thrombosis). • Ascertain whether the patient is taking vasodilator medications because they
may influence the observed peripheral arterial waveforms (rendering them low-resistance
biphasic, whereas they are normally high-resistance biphasic/triphasic). • Ascertain whether
there is a relevant cardiac history such as heart failure (which reduces flow velocity) or aortic
valve stenosis or insufficiency (which alters waveforms).
5- Perform a limited physical examination of the limbs in question.
6- Review any previous duplex studies available.
7- Select appropriate test settings, select appropriate annotation throughout test and record
images during examination.
8-The patient lies supine for at least 10 minutes before scanning to avoid residual
hemodynamic effects of exercise or muscular exertion.
9-Gloves are worn by the sonographer where there is a threat of contamination by infected
body fluids.
10-Ensure that both limbs are scanned.
11- Using grayscale imaging and color Doppler flow mapping, identify all vessels in both their
transverse and longitudinal planes and record flow velocities with pulsed-wave Doppler.
2. 12- Perform spectral Doppler using: An angle of less than or equal to 60 degrees to the vessel
wall where possible and a sample volume of 1.5mm.
* Real-Time Gray-Scale Imaging
- The diameter of the peripheral arteries that is clinically relevant varies from 1 to 6 mm.
Accurate visualization of the arterial wall requires high-resolution transducers, more than 5
MHz, to visualize all the various lesions.
- A broad frequency range of 5 to 10 MHz is preferred because it offers overall good resolution
while permitting good depth penetration, even in the thigh.
- For detailed visualization of smaller-diameter arteries, higher frequencies of 7 to 12 MHz can
be used. At these high frequencies, transducers have poor depth penetration but may be useful
for evaluating bypass grafts and the ulnar and radial arteries and smaller arteries of the hand.
- The linear phased array transducer is ideal for imaging the extremity arteries. The
transducer has sufficient length to permit rapid coverage of long arterial segments by holding it
parallel to the artery or graft long axis and by sliding it in a series of nonoverlapping
increments.
- A smaller-footprint, curved array or sector transducer can be useful for imaging the iliac
arteries.
- Gray-scale settings are adjusted to optimize visualization of intraluminal plaque or thrombus
at these sites of abnormal flow.
* Doppler Sonography
Simultaneous display of Doppler spectral waveforms and data and the gray-scale image, duplex
Doppler sonography, is the basic requisite for the evaluation of the peripheral arteries and
arterial bypass grafts.
Careful real-time control is needed to position the Doppler sample gate and accurately detect
sites of maximal blood flow velocity in arteries and bypass grafts. The transducer (doppler)
carrier frequencies can vary between 3 to 10 MHz, tending to be best lower than the
simultaneously acquired gray-scale image. Selection of a Doppler transducer frequency of
approximately 5 MHz sacrifices some sensitivity for detecting slowly moving blood but
decreases the likelihood that the system will alias at sites of rapidly moving blood, such as
stenoses or arteriovenous fistulas.
3. The ultrasound beam is directed perpendicular to the surface of interest to obtain the brightest
echo with gray-scale imaging and optimal imaging of the artery wall. The perpendicular angle is
often readily obtained, as arteries generally are parallel to the surface of the transducer.
For the Doppler component of duplex imaging, an angle of 60 degrees between the Doppler
insonation beam and the vessel wall should be maintained. This Doppler angle becomes an
important consideration when the velocity data are used to classify disease. Angles above 60
degrees can result in significant overestimation of the velocity and should be avoided. Angles
that are not relevant to the vessel wall may misrepresent the true peak velocity.
* Color Doppler sonography is an essential component of a peripheral arterial
sonographic examination. The simultaneous display of moving blood superimposed on a gray-
scale image allows a rapid survey of the flow patterns within long sections of the peripheral
arteries and bypass grafts. In general, an efficient approach to peripheral vascular sonography
relies on color flow Doppler sonography to rapidly identify zones of flow disturbances, then on
duplex sonography, including Doppler spectral analysis, to characterize the type of flow
abnormality present. The color Doppler image displays only the mean frequency shift caused
by moving structures. The pixel size (resolution) is also coarser than the corresponding pixel
size of gray-scale image. This may cause some ambiguity in alignment of the two separate
images and can cause the color Doppler information to overlap beyond the wall of the arteries.
Most manufacturers use lower transducer frequencies for the color flow image than for the
gray-scale sonographic component of the image. This approach increases the depth penetration
of the color flow image without compromising image resolution.
Color Doppler provides additional information used to detect a significant stenosis.
The pulse repetition frequency scale determines the degree of color saturation and is adjusted
so that normal laminar flow appears as a region of homogeneous color.
Stenosis results in the production of a high velocity jet and an abrupt change in the color flow
pattern. This is identified as either aliasing or desaturation (whitening) of the color display at
the site of luminal narrowing. Aliasing occurs when the flow velocity exceeds the Nyquist limit
and results in color display of the reverse flow direction (wrap around).
Color persistence is a continuous flow signal that is color of the forward direction only, in
contrast to the alternating color in normal arteries. Color persistence corresponds to the
monophasic spectral Doppler waveform of severe stenosis.
A color bruit in the surrounding soft tissue also indicates flow disturbance. This color artifact is
attributed to vibration in the surrounding soft tissue in the presence of a high velocity jet.
4. The poststenotic region demonstrates a mosaic pattern indicating turbulent flow.
Abnormalities of color flow indicate possible stenosis that is then characterized using pulsed
wave Doppler determination of velocities.
* Power Doppler sonography is a variant of color flow Doppler imaging that displays a
summation of the Doppler signals caused by moving blood. Advantages of power Doppler over
color Doppler flow imaging are (1) the blood flow information does not alias, (2) the signal
strengths are much less angle dependent, and (3) slowly moving blood is more easily detected.
A disadvantage is the loss of information pertaining to the direction of blood flow, although this
information can also be displayed.
Sensitivity is increased by a factor of 3 to 5 times with power Doppler compared with color
flow Doppler. Power Doppler can, therefore, identify very slow flow that may not be detected
by color flow Doppler. and it improves delineation of the lumen.
Power Doppler is used to differentiate high-grade stenosis from occlusion, to detect collateral
vessels, and to identify small vessel disease.
* The advent of ultrasound contrast agent, as for the power Doppler, has extended the
role of the Ultrasound in the evaluation of vascular involvement. In the proximal Lower Limb
& iliac Vessels, the location of the vessels and confirmation of occluded segments has been
made easier and, in the distal part of the leg, they make assessment of smaller vessels of calf &
foot easier. However, more works is required to evaluate further their role.
* Duplex Doppler sonography with gray-scale and Doppler spectral analysis is well accepted
as the primary noninvasive modality for detecting evidence of lower extremity bypass graft
dysfunction. It can also be used to evaluate the success of peripheral angioplasty, atherectomy,
and stent placement.
Doppler imaging of the leg arteries to determine the extent and nature of arterial lesions has
become practical with the aid of color Doppler flow imaging. Although duplex Doppler
sonography can be used to determine the presence of significant arterial lesions, the task of
evaluating the whole leg is labor and time intensive. It takes 30 to 60 minutes to map out the
arterial tree of each leg using Duplex ultrasound. With color Doppler mapping, this task can be
accomplished in 15 to 20 minutes. Color Doppler imaging also improves the accuracy of
Doppler ultrasound as a diagnostic test for detecting and grading the severity of peripheral
artery disease.
5. A full scan of the lower limb arteries can be time consuming: In some case, a full scan (from
Aortic Bifurcation to ankle or foot) is required but in other cases, the examination can be
tailored to specific levels depending on the diagnostic information required. It is therefore
useful if the diagnostic question can be clearly defined, so that the most appropriate
examination can be performed.
Since quantification of stenoses is based on velocities and velocity increases, scanning of the
arteries is undertaken longitudinally.
Atherosclerotic changes produce inconsistent effects in the B-mode image. Because of this, the
colour image is used extensively to identify the location of the artery, voids in the flow signal
indicating occlusion and regions of increased velocity suggesting narrowing of the lumen.
Areas of concern can then be tested using spectral Doppler. For linear arrays, beam steering can
enhance the Doppler image in both colour and spectral modes, although attenuation is least
when the Doppler beam is unsteered.
Although limited, real-time gray-scale sonography is useful for evaluating the presence of
atherosclerotic plaque or confirming the presence of extravascular masses.
The degree of stenosis is obtained by measuring peak systolic velocity from the spectral
Doppler sonogram. As usual when using spectral Doppler ultrasound to calculate velocities,
care should be taken when using beam/flow angles greater than 60°, although the use of
velocity ratios means that errors are usually acceptable at angles up to 70°.
When determining occlusion, low pulse repetition frequencies and power Doppler should be
used to check for low volume, low velocity flow in any residual lumen in the vessel.
Flow waveforms in healthy arteries exhibit pulsatile flow with reverse flow in late systole –
triphasic or biphasic flow.
Normal Arterial Waveforms of CFA, Pop A and TPA.
Changes in flow waveform shape can be an indication of proximal disease or distal occlusion.
Although attempts have been made to use measurement of subtle changes to indicate proximal
disease, these have not become established in clinical practice. However, experienced
sonographers use visual changes in the waveforms and abnormally low or high velocities as
indications of abnormal circulation warranting further investigation.
Abnormal superficial femoral artery flow waveform. The low velocities, absent diastolic flow and short
initial peak are indicative of severe distal disease, in this case an occlusion of the femoral artery at mid-thigh
level.
6. * During the scan:
Attempt to characterize the pathology (e.g., wall thickening/calcification [medial calcinosis])
and the appearance, length, location and extent of plaque.
If aneurysmal dilation is identified in transverse scanning, measure the diameter, length, and the
aneurysmal neck, as well as any endovascular treatment relevant details (see Chapter 7).
Obtain representative peak systolic velocity (PSV) measurements along the vessels every 2 to 3
cm.
When a lesion is detected with grayscale scanning and color Doppler flow mapping, record
PSV measurements: Immediately proximal to the site of stenosis, within the stenosis and
immediately distal to it.
Note any obvious collateral vessel formation associated with a significant lesion.
Document any identified retrograde flow.
* Main Steps of the examination of the Lower Limb Arteries
1- Patient Supine: Scan CFA, proximal PFA and SFA down the adductor canal.
2- Patient (IpsiLateral) Decubitus: Scan adductor canal, Pop.A. to bifurcation and TPT, scan
PTA and Per.A.
3- Patient Supine: Scan ATA. Scan Iliac arteries and Infrarenal aorta.
* Scanning Technique : Common Femoral, Profonda Femoris and Superficial
Femoral Arteries:
The examination begins with the patient lying supine on the couch, limb being scanned is
externally rotated and the knee slightly bent.
A high frequency linear array transducer, usually 5-12 Mhz, should be used; depending of the
built of patient and the performance of the ultrasound system. However, Lower Frequencies
curvilinear arrays may be required to examine the arteries in the adductor canal or in large
patient, especially as it produces a greater field of view.
The Distal external Iliac / Common femoral artery is located using colour Doppler as it
leaves the pelvis under inguinal ligament, at the level of the groin, lateral to the Common
7. femoral vein. Imaging should be performed in the longitudinal plane, and a spectral Doppler
should be obtained from this artery, even if flow appears normal on colour Doppler and there is
no evidence of local disease, as change in this may indicate the presence of significant disease
proximally, necessitating a careful direct examination of the iliac vessels.
The FCA should be followed distally to its bifurcation into the profunda femoris and superficial
femoral arteries using colour Doppler and Doppler signals obtained from the origin of both the
superficial femoral artery and the deep femoral artery.
The profunda femoris artery dives deeply beyond its origin and should be examined over its
proximal 5cm, especially in patients with severe superficial femoral disease, in order to assess
the amount of collateral flow or its potential value as a graft origin or insertion point.
The SFA is then followed distally as it courses down the medial aspect of the thigh using color
Doppler. It’s often better to move the transducer in sequential steps, rather than sliding it down
the tighs as most machines require a few frames of sampling at each position to provide a
steady Image. In addition, the moving transducer generates color Doppler noise over the image,
obscuring vascular details.
Doppler Spectra are obtained as necessary at points and areas of questionable disease and
narrowing. Even if there no abnormalities in colour Doppler, it is good practice to obtain
routine spectral assessment in the upper, middle and lower thigh, in order to confirm that there
is no alteration in the waveform that suggests disease.
Sometimes, the artery is difficult to see on both B-mode and colour or power Doppler
because of calcification and weakness or absence of signal, especially at depth and in patients
with diabetes or chronic renal failure. In these cases the artery can be visible by vitue of
calcified plaques in the wall of vessel. Alternatively, the Femoral Superficial Vein, lying behind
can be used as a guide to the position of the artery and spectral Doppler used to demonstrate the
absence or presence of arterial flow. Echo-Contrasting Agents can be used if there is any
continuing uncertainty concerning the patency of the artery.
There are 3 indirect signs of significant disease wich might be apparent during the
examination and wich should prompt a careful review if a cause for these changes has not been
identified :
1- Color Doppler may show the presence of collateral vessels in the muscles of the thigh.
2- Collateral Vessels may be seen leaving or joining the main artery.
3- The character of the specral waveform may show a change between 2 levels indicating a
segment of disease somewhere between these 2 points.
* Scanning Technique : The adductor Canal and popliteal fossa
8. The patient is then turned into a lateral decubitus position so that the medial aspect of the leg
being examined is uppermost as the distal portion of the superficial femoral artery may be easier
to evaluate from the distal posterior thigh as well as the popliteal artery in the popliteal region.
It’s even better than the prone position as it allows to access in continuity to the lower
superficial femoral artery, in the adductor canal area, the popliteal region and the medial calf.
The region of the adductor canal must be examined with a great care as it is a site where a short
segment stenosis or occlusion may be present, and this section of the vessel can be difficult to
visualise as it passes deep to the thigh muscles. In some cases the use of a lower scanning
frequency may help visualisation. The SFA is examined as far down as it can be followed on
the medial aspect of the thigh; The popliteal artery (Pop.A) is then located in the popliteal
fossea and followed superiorly.
In difficult cases, a mark can be put on the skin of the medial thigh to show the lowest segment
of SFA seen in Supine position; the Pop.A is then followed superiorly in the decubitus position
until the transducer reaches the level of the skin mark, ensuring that the vessel has been
examined in continuity. If concern persists about disease in this segment, spectral Doppler
waveforms from the lower superficial femoral artery and upper popliteal artery segments should
be obtained to ensure that there are no changes that might suggest significant intervening
disease.
The Pop.A is then followed through the popliteal fossa, lying deep to the vein, and followed down
to the point of division into the tibioperoneal trunk (TPT) and anterior tibial artery (ATA).
Following the distal popliteal artery in a longitudinal plane, the origin of the anterior tibial artery
can usually be visualized diving deep on the monitor. The anterior tibial artery can only be
followed for a short distance from this approach. A Doppler spectral waveform should be
recorded in the upper and inferior half of this Pop.A.
* Scanning Technique : Calf Arteries
The complexity of the assessment of the calf arteries depend of the clinical situation and local
skills as well as type of radio - surgical team approach.
In general, the TPT and its bifurcation, Proximal ATA from posterior approach , the dorsalis
pedis artery midway between lateral and medial malleoli and the posterior tibial artery at the
ankle level immediately posterior to the medial malleolus are assessed by colour and spectral
9. Doppler. If neither the posterior tibial nor the dorsalis pedis arteries are visualized, the peroneal
artery is to search anterior or posterior to the lateral malleolus.
If the examination is to exclude proximal disease that would benefit from angioplasty or bypass
grafts, then it is usually sufficient to assess the three calf arteries at the upper and mid- calf
level, recording whether they are patent or not, in order to provide some assessment of the state
of the distal run off.
In other cases, a more detailed examination is required to clarify changes seen in CTA or
Arteriography or if a distal insertion point for distal graft is been thought. The increased
sensivity of power Doppler is useful to detect weak signals from small or diseased but patent
Vessels. Patency of the distal anterior tibial, posterior tibial and peroneal arteries is identified.
Arteries are described in terms of diameter, patent length with evidence of stenoses, waveform
shape and evidence of communication with the pedal arch. There have been fewer studies
reporting on ultrasound scanning of infrapopliteal arteries. In comparison with scanning the
proximal arteries, investigation of vessels in the lower leg is time-consuming with a lower
reported success rate, especially for peroneal artery stenosis. (48,49 in 3). The presence of
extensive, severe calcification can preclude full investigation of calf arteries; this is a practical
constraint on the many patients presenting with diabetes or chronic renal failure.
Nevertheless, a study comparing angiography and duplex scanning assessment of vessel
patency (48 in 3) concluded that agreement between the two modalities was similar to agreement
between radiologists reporting on angiograms. For these arteries, colour flow is particularly
useful for identifying the course of vessels and the presence of collateral flow.
Ultrasound has been shown to be effective in evaluating run-off vessels suitable for
femorodistal reconstructions(50 in 3). For these preoperative examinations, flow and velocities are
often very low indeed. High-frequency transducers are required using low colour and spectral
pulse repetition settings.
The tibial-peroneal trunk extends into the calf from the popliteal artery. This segment is
another site of predilection of disease and careful assessment is required.
The PTA: is usually the easier of the two branches of the TPT to locate. Often, it can be
localised by placing probe in longitudinal section on medial aspect of mid-calf area behind the
tibia, using color or power Doppler to show course of the artery, wich can be followed up and
down the calf. The PTA can also be followed as it passes behind the medial malleolus, where its
position is constant, and then followed back up the leg.
10. The Peroneal artery runs more deeply down the calf than the PTA, lying closer to the post
aspect of the tibia and the interosseous membrane. It can be examined from different
approaches:1- from posteromedial approach similar to that used for PTA ( in Ipsilateral lateral
decubitus position). This artery , by this approach, lies deep and runs parallel to the PTA. 2- It
can also often be seen from the anterolateral approach used for ATA (in supine position) as it
runs behind the interosseous membrane. 3-Posterolateral approach (in contolateral Decubitus)
may be of value in some cases.
As explained above, The proximal anterior tibial artery can only be followed for a short distance
from a posterior approach after the bifurcation of the popliteal artery. The remainder of the vessel
can be located and followed distally from anterolateral approach (in supine position) through
the extensor muscles lying between the Tibia & Fibula. The two bones can be identified in
transverse section and the interosseous membrane located passing between them. The ATA lies
on the membrane and can be located on color Doppler, in either the longitudinal or transverse
plane. It usually lies nearer the fibula than the tibia. More distally, it can be followed to the level
of the ankle.
In obese or oedematous legs or if blood flow impaired by disease, the PTA & the other arteries
of the calf may be difficult to locate. Scanning with Colour doppler in transverse plane using
some angulation toward feet or head may show the relative position of PTA and peroneal
arteries. Alternatively, the associated veins can be used to identify the region of the relevant
artery: Squeezing the foot or lower calf will augment flow in the deep veins, allowing these to
be identified in either longitudinal or transverse scan plane. This later approach can be also
facilitated if the patient can sit on the edge of the couch with their leg dependent. Using power
Doppler may be also of help.
* Scanning Technic: The foot arteries are not usually examined but the Dorsalis Pedis
artery may be examined in front of the Ankle Joint, before it passes deep to the metatarsals .
This is indicated if the artery is being considered for the insertion of a femorodistal Graft or
there are particular questions about the arterial circulation in the foot.
Power D improve assessement of smaller vessels of calf & foot. Further Works are necessary
to assess echo enhancing agents in the arteries of distal leg and foot vessels.
* Scanning Technic: Aorta and Iliac Arteries
11. Examination of the iliac vessels is carried out as part of general survey of the lower limb
arteries or if the clinical picture suggests a need to confirm or to exclude disease affecting
these vessels or if the the Doppler finding at the groin suggest the likelihood of significant
proximal disease.
Some examiners will prepare patients for aorto-iliac Doppler examination with laxatives and
low-residue diets to reduce the difficulties caused by gas if it is considered likely that these
vessels will be examined, although most center do not do this routinely.
The aorta and proximal iliac vessels are best scanned with a curvilinear or phased array low
frequency transducer (2.0-3.5 MHz).
Begin the scan of the abdominal aorta at the level of the xiphisternum, slightly to the left of
the midline (or above if the coeliac axis is more proximal). Use both transverse and longitudinal
views to measure the maximal anteroposterior and transverse diameter of any aneurysmal
dilatation. Document the location of aneurysmal disease with respect to the renal artery ostia.
Turning the patient obliquely or into a decubitus position may be necessary to optimize arterial
visualization in the presence of extensive bowel gas. Note, in passing, the splanchnic and renal
branches of the aorta.
The aortic bifurcation is best seen with the patient turned to the left side and with the
transducer placed just in front of the right iliac crest in a longitudinal plane. The distal aorta can
usually visualize with the origin of both common iliac arteries. Doppler signals should be
obtained from all three vessels at this location. Continue to scan down the common and external
iliac arteries
Superiorly, the Common Iliac a. can be identified arising at the aortic bifurcation and then
followed distally. Firm pressure with the transducer will displace intervening amount of bowel
gaz to a large extent, although care must be taken not to compress the artery and produce a false
impression of stenosis.
The Ext Iliac a. can be scanned down from the common iliac a. This artery can, however, most
easily be located by continuing to scan proximally from the common femoral artery at the groin
(located at a point midway between the midsymphysis pubis and the anterior superior iliac
spine) just below the inguinal ligament and moving diagonally toward the umbilicus for a
variable distance. The vein lying behind the artery, can be used to identify the probable
location of artery , if it is not apparent. Colour or Power Doppler may also help locate the
vessel; even if it is not visible on real-time Image.
The internal Iliac a. may be seen arising from the common Iliac a. and passing deeply into the
pelvis. This is a useful landmark as visualisation of the internal iliac a. origin, on tracking both
the external iliac artery upwards and the common iliac a. downwards, means that the iliac
arteries have been examined in their enterity.
12. The orientation of Iliac arteries as they pass round the pelvis and the use of sector or curved-
array Transducers can lead to problems with beam-Vessel geometry and obtaining satisfactory
angles of insonation. However, careful attention to the position of the Transducer will usually
allow an appropriate angle to be obtained.
To help evaluate, e.g., the internal and external iliac arteries, the transducer can be placed
between the iliac crest and the umbilicus, the patient turning into a lateral decubitus position
(side being evaluated up).
If difficulty is encountered in locating the common iliac artery from the aortic bifurcation, it can
be followed upward from the external Iliac a.
Doppler waveforms should obtain from the internal and external iliac arteries, noting direction
of blood flow and velocity.
At the end of the arterial duplex examination, the ultrasound gel should be removed from the
patient with a clean towel, and any excess gel should be removed from the transducer. The
transducer should be cleaned using a disinfectant.
* Interpretation and Reporting
Normal Study
- Typical triphasic/biphasic Doppler waveform
- No evidence of plaque, calcification, or aneurysmal dilation on grayscale imaging
- Normal flow velocities
Abnormal Study
- Intraluminal echoes identified
- Abnormal waveforms
- Flow velocity changes
Classification of Stenosis
a- Less than 50%: plaque visualized on grayscale imaging. Triphasic/biphasic waveforms.
30% to 100% increase in PSV compared with that immediately proximal to the site of stenosis.
b- Between 50% and 99%: Plaque visualized. Loss of reverse flow component (variable).
More than 100% increase in peak systolic flow velocity compared with that immediately
13. proximal to the site of stenosis. Evidence of poststenotic turbulent/disordered flow. Color flow
representation of narrowed flow channel.
c- Complete occlusion: Intraluminal echoes observed throughout vessel. Absence of color and
spectral Doppler signals. Reconstitution postocclusion: Resumption of flow visualized by color
Doppler and Spectral Doppler flow pattern usually contains both forward and reverse flow
elements (influenced by reentry vessel flow).
Descriptions of Plaque/Stenosis
a- Calcified: hyperechoic lesion causing acoustical shadowing.
b- Heterogeneous or complex: lesion of mixed echogenicity causing no acoustical shadowing.
c- Anechoic: hypoechoic, poorly delineated lesion but possibly causing flow disturbance
d-Smooth: surface contour of lesion is smoothly defined.
e- Irregular: rough and irregular luminal surface.
Other Lesions/Syndromes
a- True aneurysm
• Focal dilation of arterial wall
• Pulsating mass seen on grayscale imaging
• Possible visualization of an intimal flap if dissection is present.
• Turbulent flow in the aneurysmal sac
• Intraluminal heterogeneous echoes suggestive of thrombus may be present.
b-False (or pseudo) aneurysm
• Pulsating mass identified on grayscale and color Doppler imaging that is connected to the
artery via a “tract”.
• Pattern of reciprocating high-velocity anterograde and retrograde (“to-and-fro”) flow within
the tract
• Turbulent flow is present the body of the false aneurysm (apparent by color and spectral
Doppler)
c-Arterial compression syndrome (e.g., popliteal entrapment)
• The artery may have normal appearance and show normal waveform contours at rest.
• Even after exercise, although ankle-brachial values might diminish somewhat, there is often
no dramatic change.
• However, if the patient is asked to perform the provocative maneuvers that actually cause pain
(e.g., plantar and dorsiflexion), high-velocity turbulent flow accompanied by visualization of a
temporarily narrowed or obliterated flow channel by color Doppler can be readily seen.
15. 6- Guidelines for Noninvasive Vascular Laboratory Testing: A Report from the American Society of
Echocardiography and the Society of Vascular Medicine and Biology, Gerhard-Herman et al, Journal of the
American Society of Echocardiography 2006; 19:955-972, doi:10.1016.
7- ULTRASOUND OF THE LEG ARTERIES – Normal. http://www.ultrasoundpaedia.com/normal-leg-
arteries/
