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.

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.

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.

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.

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.

* 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

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

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

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.

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

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.

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

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.

d-Arteriovenous fistula

• Connection between artery and vein identified with color Doppler

• Pulsatile flow identified in the vein distal to the fistula

• Monophasic flow patterns possibly present in the artery proximal to fistula

• High-velocity turbulent flow seen in arteriovenous connection

• Observation of the following findings: 1-An increase in diastolic flow compared with

proximal values. 2-High-velocity flow within a persistent vein branch (rather than in the graft

itself as in stenosis). 3-Mean velocities in proximal portions of the graft that are significantly

higher than those obtained in normal or stenotic grafts. 4-PSVs measured proximal to the fistula

that are significantly greater than those measured distally.

Reporting

Ultrasound images are constrained by the transducer width and field of view. This presents

difficulties in presenting findings to referring clinicians. It is common to present ultrasound

findings on a diagram of the leg, highlighting the presence and size of occlusions and

aneurysms, the site and severity of stenoses and major collateral pathways identified at the scan.

II- References

1- The Peripheral Arteries, Paul L Allan in Clinical Doppler Ultrasound, 3d Edition, Myron A Prozniac &

Paul L Allan,Chap 4, p.82-104, Churchill Livingstone, 2014, e-book ISBN 9780702055379

2- Evaluation Of Peripheral Arterial Disease Of Lower Limb By Duplex Colour Doppler Study. National Journal

of Medical and Dental Research, October-December 2015: Volume-4, Issue-1, Page 41-47

3- Peripheral arteries, Colin R. Deane and David E. Goss in Clinical Ultrasound 3d Edition, Paul L. Allan-

Grant M. Baxter- Michael J. Weston, Chap 63, p.1197- 1226, Churchill Livingstone, © 2011 Elsevier Limited.

ISBN: 978-0-7020-3131-1.

4- Lower Extremity Arterial Disease in PRINCIPLES of VASCULAR and INTRAVASCULAR

ULTRASOUND, Stuart J. Hutchison- Katherine C. Holmes, Chap5, p.96 -132, Copyright © 2012 by Saunders,

an imprint of Elsevier Inc., ISBN 978-1-4377-0404-4

5-The Peripheral Arteries , Joseph F. Polak and Jean M. Alessi-Chinetti, in DIAGNOSTIC ULTRASOUND,

FOURTH EDITION, Carol M. Rumack - Stephanie R. Wilson- J. William Charboneau- Deborah Levine,

Chap 26, p. 998- 1022, Copyright © 2011 by Mosby, Inc., an affiliate of Elsevier Inc.,ISBN: 978-0-323-05397-

6.

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/