Doppler ultrasound of lower limb arteries

Doppler ultrasound of lower limb arteries

Samir Haffar M.D.

Assistant Professor of internal medicine

Doppler US of lower limb arteries

Anatomy of lower limb arteries

Normal Doppler US of lower limbs arteries

Duplex US criteria for arterial evaluation

Causes of lower limb arterial diseases

Doppler US of bypass graft

Anatomy of abdominal aorta & its branches

Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004.

• Lies to left of midline

• Inferior vena cava to its right

• Extends from L1 to L4

• Gives visceral branches

• Gives phrenic & lumbar branches

Anatomy of iliac artery

CIA (4 – 5 cm long)

From L4 to sacroiliac joint

Divides into IIA & EIA

Left to corresponding CIV

EIA (twice long of CIA)

Superficial to corresponding vein

Gives inferior epigastric artery

Becomes CFA at inguinal ligament


Anatomy of femoral & popliteal arteries


Common femoral artery (4-6 cm long)

Lies superficially in the groin

Divides to SFA & PFA

Superficial femoral artery

Extends down medial thigh

Passes deep through adductor hiatus

Popliteal artery

Commences below adductor hiatus

Passes vertically through popliteal fossa

Divides to tibio-peroneal trunk & ATA

Anatomy of crural arteries


There are several interconnection

So that each artery can supply all regions

Normal diameter of lower limb artery

• Sub-diaphragmatic aorta 21 – 24 mm

• Infra-diaphragmatic aorta17 – 20 mm

• Common iliac artery 10 – 12 mm

• External iliac artery 8 – 10 mm

• Common femoral artery 7 – 9 mm

• Superficial femoral artery 6 – 8 mm

• Popliteal artery 4 – 6 mm

Stiegler H & Brandl R. Ultraschall in Med 2009 ; 30 : 334 – 363.

Anatomical variations of lower limb arteries

May be occasionally encountered

Artery Variation

Aorta Duplication (very rare – duplication image artifact)

Thrush A, Hartshorne T. Peripheral vascular ultrasound: How, why and when.

Elsevier Churchill Livingstone, London, 2nd edition, 2005.

ATA High origin across knee joint

May be small or hypoplastic (2%)

Peroneal artery Origin from ATA rather than tibio-peroneal trunk

CFA bifurcation Bifurcation can sometimes be very high

EIA Aplasia with blood supply to leg via strong IIA

Duplicated aorta or duplication artifact

Meuwly JY et al. Ultraschall Med 2011 ; 32 : 233 – 236.

Duplication image artifact frequent in lower abdomen:

False cases of twin pregnancies

Double intra-uterine devices

Gray-scale US

Duplicated aorta

Color Doppler US

2 aortic lumen filled with color

Tiny sliding probe to right

Only one lumen filled with color

Doppler US of lower limbs arteries






Arteries scanned in Doppler US of lower limbs

• Tibio-peroneal trunk

• Posterior tibial artery

• Anterior tibial artery

• Peroneal artery

• Dorsalis pedis artery


Aorta & the following arteries on both sides

• Common iliac artery

• External iliac artery

• Common femoral artery

• Profunda femoris artery

• Superficial femoral artery

• Popliteal artery

Normal wall of the artery3 layers

Transducer positions for scanning AA


Elsevier Churchill Livingstone, London, 2nd edition, 2005 .

Sagittal or

longitudinal

Transverse

Coronal

Normal aortic bifurcation

Normal external iliac vessels

Transverse scan

Region of the groin

Normal SFA & PFA

Transverse view Longitudinal view

Region of adductor canal & popliteal fossa

Region of adductor canal is difficult to evaluate

Region of adductor canal & popliteal fossa

Distal superficial femoral vessels Normal popliteal vessels

Insonation of leg arteries


Posterior tibial artery

Peroneal artery

Medial approach

Anterior tibial artery

Anterolateral approach

Proximal

Normal anterior tibial artery

Normal posterior tibial vessels

Proximal Distal

Normal peroneal vessels

Longitudinal view Transverse view

Normal triphasic waveform of peripheral arteriesArterial high resistance flow

Narrow frequency band

Steep systolic increase

Quick drop

Early diastolic reverse flow ( of systolic flow amplitude)⅕

Late diastolic short forward flow

ABPI: Ankle Brachial Pressure Index


Normal PSV of lower limb arteries

Pulsatility index

Most commonly used of all indices

S: Systolic

D: Minimum diastolic

M: Mean

PI: S – D / M

Normal PI: 4 – 13 (average 6.7)

Depending on location of peripheral arteries

Factors influencing pulsed Doppler waveform Complicate evaluation

• Cardiac pump function Cardiac insufficiency

• Aortic valve function Aortic stenosis/insufficiency

• Course of vessel Tortuosity

• Vessel branching

• Peripheral vascular resistance Peripheral inflammation

Polyneuropathy

Warm or cold extremity

Vaso-spastic disordersStiegler H & Brandl R. Ultraschall in Med 2009 ; 30 : 334 – 363.

Arterial monophasic flow

• Hyperemic (normal PSV& normal RT*)

Exercise

Fever

Downstream infection

Temporary arterial occlusion by blood pressure cuff

• Tardus-Parvus waveform (low PSV & longer RT)

Distal to severe stenosis or occlusion

*Rise time: Time between beginning of systole & peak systole

Hyperemic monophasic flowFollowing exercise

Normal triphasic waveform

Normal DPA at rest

Monophasic hyperemic flow

Following exercise

Hyperemic flowPhlegmon of foot

Monophasic waveform

Normal PSV

Normal rise time


Anatomy (course, variants) Vessel contour (aneurysm, stenosis) Wall structures (calcification, plaque, cyst) Pulsation (axial, longitudinal) Perivascular structures (hematoma, abscess, tumor, muscle)

B-mode

Demonstration of flow Flow direction Flow pattern (laminar, turbulent) Flow profile (monophasic, triphasic) Flow velocity

Doppler

Schäberle W. Ultrasonography in vascular diagnosis.

Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.

Causes of arterial diseases

Atherosclerosis

Thrombosis or embolism

Aneurysm

Intimal dissection

Pseudo-aneurysm

Arterio-venous fistula

Arteritis

Entrapment syndrome

Cystic adventitial disease

Most common cause

Peripheral arterial diseaseFontaine & Leriche classification

Stage Complains

I Asymptomatic

II aII b

Mild claudication Moderate to severe claudication

III Ishemic rest pain

IV Ulcer or gangrene

Underdiagnosed & therefore undertreated disease

Ankle Brachial Pressure Index (ABPI)Continuous wave Doppler (takes 10 - 15 min)

Posterior

tibial artery

Dorsalis

pedis artery



Peroneal artery

Highest ankle pressure / highest brachial pressure

Grading arterial disease using ABPI

ABPI Comment

> 1.3 Falsely high value (suspicion of medial sclerosis)

0.9 – 1.3 Normal finding

0.75 – 0.9

Mild PAD

0.4 – 0.75

Moderate PAD

< 0.4

Severe PAD

ABPI: Ankle Brachial Pressure Index


ABPI in diabetics

Calcification of vessel walls

Beaded appearance of color flow

Ankle pressure 280 mmHg

Brachial pressure 120 mmHg

ABPI 2.3

Falsely elevated recordings in diabetic patients

Calcified & rigid arterial walls

Direct & indirect signs of stenosis

Proximal to stenosis

At site of stenosis

Distal to stenosis

Grading of lower limb artery stenosis Flow pattern proximal to lesion

High resistance, low volume waveform

Characteristic shoulder on systolic downstroke

Due to pulse wave reflection from distal disease

Shoulder

Grading of lower limb artery stenosis PSV at site of stenosis

Grading of lower limb artery stenosis

PSV ratio

Robbin ML et al. Ultrasound Clin 2006 ; 1 : 111 – 131.

Proximal: 2 cm proximal to stenosis

At stenosis : Same Doppler angle if possible

Grading of lower limb artery stenosis

PSV ratio

Grading of lower limb artery stenosisRanke scale

Left vertical line: Pre-stenotic PSV

Right vertical line: Intra-stenotic PSV

Middle vertical line: Degree of stenosis in %

Ranke C et al. Ultrasound Med & Biol 1992 ; 18 : 433 – 440.

Grading of lower limb artery stenosisEffect of collaterals

Excellent collaterals

Poor collaterals

Absence of collaterals

Grading of lower limb artery stenosis Flow pattern distal to lesion

Tardus: Longer rise time

Parvus: Low PSV

Severe stenosis or occlusion

Tardus-Parvus waveformDamping waveform

Increased systolic rise time

Loss of pulsatility

Lower limb arterial stenosesMost common sites


Aorto-iliac: 25 %

Femoro-popliteal: 65%

Infra-popliteal: 10%

Stenosis of PFA / Aliasing

Grading of arterial stenosis

SFA:

PSV of A 69 cm/sec

PSV of B 349 cm/sec

B / A 349 / 69 = 5

> 80% diameter stenosis



Two severe stenosis of SFA

2 severe stenoses demonstrated in SFA

Areas of color flow disturbance & aliasing (arrows)



Calcified atheroma in SFA

Drop-out of color flow signal in parts of lumen



Occlusion of the CIA

Occlusion in CIA

Reversed flow in IIA (blue) to supply flow to EIA (red)



Arterial occlusion & collaterals

Short occlusion of mid-SFA (large arrow)

Large collateral at both ends of occlusion (small arrows)



Diagnostic reliability of peripheral arterial diseaseSystematic review – DSA as gold standard

Collins R et al. BMJ 2007 ; 334 : 1257 – 1266.

MRA CTA CDUS

No of studies 6 5 7

SensibilityMedian (range)

94%(85 – 100)

97%(89 – 100)

90%(74 – 94)

SpecificityMedian (range)

99.2%(97 – 99.8)

99.6%(99 – 100)

99%(96 – 100)


Atherosclerosis (most common cause)


Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


FA lumen filled with hypoechoic thrombus or embolus

Good delineation of vessel wall without signs of plaque

Normal flow in adjacent FV

Hamper UM et al. Radiol Clin N Am 2007 ; 45 : 525 – 547.

Thrombosis or embolism / Femoral artery




Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Compression syndrome (entrapment syndrome)


Definition of aneurysm & ectasia

Aneurysm

Diameter increase > 50% of normal expected diameter

Ectasia

Diameter increase < 50% of normal expected diameter

Considerable variability in normal diameter of arteries

Depends on physical size, sex, & age

Johnston K W et al. J Vasc Surg 1991; 13:452 – 458.

Types of aneurysmTrue aneurysm

False aneurysm

Dissecting aneurysm

Common sites for lower limbs aneurysms


Abdominal Aortic Aneurysm (AAA)

• Normal size of abdominal aorta 1.5 – 2.5 cm

• Ectatic aorta 2.5 – 3 cm

• Aortic aneurysm > 3 cm

• Annual growth rate of aneurysms 0.33 cm/year

measuring between 4 & 5.5 cm

* Bhatt S et al. Ultrasound Clin 2008 ; 3 : 83 – 91.

Classification of abdominal aortic aneurysms

Classification Categories

By location

Suprarenal: Above origin of renal areteries (very rare) Juxtarenal: Where renal arteries originate Infrarenal: Below origin of RA (most common)

Bhatt S et al. Ultrasound Clin 2007 ; 2 : 437 – 453.

By morphology Fusiform (most common) Hourglass Saccular

By etiology Atherosclerotic (most common) Inflammatory (5% – 10%) Mycotic (1%): saccular, salmonella & SA, high mortality

Measurement of widest part

Measurement technique of aneurysm

Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004 .

Measuring diameter of AAAIncorrect measurement Correct measurement


Springer-Verlag, Berlin, 2nd edition, 2011.

Correct diameter measured by rotating transducer clockwise

until round image of aorta comes into view

Shapes of aneurysm

Fusiform Saccular

Most frequent

Double aneurysm

Hourglass aorta

Abdominal aortic aneurysm / Fusiform

Transverse image

Anteroposterior diameter

from outer wall to outer wall

Sagittal image

Diameter measured in transverse

image larger due to obliquity


Abdominal aortic aneurysm / Hourglass

Bhatt S et al. Ultrasound Clin 2007 ; 2 : 437 – 453.

Two discontinuous focal segments of aneurysmal dilatation

Aortic diameter in between is normal in caliber

Abdominal aortic aneurysm / Saccular

Saccular or mycotic aneurysm

Thrombus seen as low-level echoes within aneurysm

Sagittal image of abdominal aorta

Abraham D et al. Emergency medicine sonography: Pocket guide.

Jones & Bartlett Publishers, Boston, MA, USA, 1st edition, 2010.

Battaglia S et al. J Ultrasound 2010 : 13 : 107 – 117.

Abdominal aortic aneurysm / Swirling flow

Pseudo ‘‘yin-yang sign’’

Similarity in appearance to pseudo-aneurysm finding

Suprarenal aortic aneurysm

Schuster H et al. Ultraschall Med 2009 ; 30 : 528 – 543.

Cross section viewLongitudinal section view

Inclusion of visceral & renal

arteries

Perfused lumen

& narrow circular thrombus

Infrarenal aortic aneurysm Distance between RA & upper limit of aneurysm



SMA

LRV

Abdominal aortic aneurysm / Rupture High mortality rate (90%)

AAA with peripheral thrombus

Small hypoechoic area (wall rupture)

Hypoechoic structure at upper end

Presence of active bleeding

No further imaging confirmation

Taken directly to OR Bhatt S et al. Ultrasound Clin 2007 ; 2 : 437 – 453.

Abdominal aortic aneurysm / Dissection

B-mode image Color flow imaging

True l

umen

Fals

e lum

en

Dissection into thrombus & vessel wall has occurred



Abdominal aortic aneurysm / Thrombus liquefaction

Area of thrombus liquefaction may be confused with dissection

Large thrombus separate area of liquefaction from lumen

Thrombus

Lumen

Liquefacti

on



Diameter of aneurysm (indication for surgery) Shape of aneurysm (Fusiform, hourglass, sacular) Partial thrombosis Infra-renal or supra-renal Involvement of iliac arteries: common, internal

Additional criteria if endovascular treatment

Distance of proximal end of aneurysm to renal artery Degree of angulation in case of elongation of infra-renal aorta Conic neck of aneurysm Lumen of CFA (large enough for stent insertion)

Relevant color duplex findings in AAA


Springer-Verlag, Berlin, 2nd edition, 2011.

Stent-graft expands to make firm

circumferential contact with

‘neck’ of relatively normal aorta

between RA & upper end of AAA

each CIA below aneurysm

Endovascular aortic aneurysm repair (EVAR)First performed by Parodi from Argentina in 1990 1

1 Parodi JC et al. Ann Vasc Surg 1991 ; 5 : 491 – 499.2 Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004.

Stent-graft

Endoleak after EVARPersistence flow in aneurysm lumen after procedure

• Increase in aneurysmal diameter with risk of rupture

• 20 – 40% at any time after graft placement1

• Lifelong surveillance 1st month, 6th month, yearly2

• Modalities CTA: gold standard

CDUS/CEUS: acceptable alternative

MRA – DSA

1 Demirpolat G et al. J Clin Ultrasound 2011; 39 : 263–269.2 Stavropoulos SW et al. Radiology 2007;243:641.

Determination of endoleak & aneurysmal size

Type IVPorosity of graft material (resolved in 1 month)

Type IIIPerforation & tear in graft material (rare)

Type I Failure of proximal or distal attachment sites

Type IIFlow through aortic or iliac branches (common)

Endoleak following EVAR

White GH et al. J Endovasc Surg 1996 ; 3 : 124 – 5.

Carrafiello G et al. Cardiovasc Intervent Radiol 2006 ; 29 : 969 – 974.

Type VSource not identified (controversial)

EVAR / Mirror artifact

Demirpolat G et al. J Clin Ultrasound 2011 ; 39 : 263 – 269.

Synchronous pulsatility with flow in patent graft

Changing position while examining from different aspects

Spectral analysis aids in reducing false positive

Mirror image behind patent limbs of stent graft

EVAR / Poorly organized thrombus

Aneurysmal sac contains mix of echoes

Large anechoic area (A) which could represent an endoleak

No flow detected (region of poorly organized thrombus)

Hartshorne T. Ultrasound 2006 ; 14 : 34 – 42.

Types of endoleakType I: Distal attachment site

Type II: Patent lumbar artery

Thrush A et al. Peripheral vascular ultrasound. Elsevier, London, 2nd edition, 2005.Hartshorne T. Ultrasound 2006 ; 14 : 34 – 42.

Type II: Inferior mesenteric artery

Type I: Proximal attachment site

Selective screening for AAA

• Selective screening

3 important risk factors Males

Age > 65 years

History of smoking

• Effectiveness of screening

4 RCTs including more than 125,000 men

Reported results for up to 5 – 10 years of follow-up

Reduction in mortality from 68% to 21%

Lederle FA. Ann Intern Med 2003 ; 139 : 516 – 22.

Popliteal artery aneurysm / Partial thrombosis

Transverse CDUS Sagittal pulsed & CDUS

Hamper UM et al. Radiol Clin N Am 2007 ; 45 : 525 – 547.

Most common peripheral aneurysm

70% of peripheral aneurysms

Popliteal artery aneurysm / Complete thrombosis

Useche JN et al. RadioGraphics 2008 ; 28 : 1785 – 1797.

Thrombosed popliteal aneurysm occluding PA

Patency of popliteal vein clearly demonstrated

Differential diagnosis of pain in popliteal fossa

• Arterial aneurysm or pseudoaneurysm• Arterial dissection• Venous aneurysm • Adventitial cystic disease• Baker’s cyst• Enlarged lymph nodes• Hematoma, seroma, abscess • Muscle tears• Muscle tumors

Popliteal vein aneurysm / Rare

1 MacDevitt DT et al. Ann Vasc Surg 1993 ; 7 : 282 – 286.2 Graham RN et al. Am J Surg 2010 ; 199 : e5 – e6.

Dilatation twice or 3 times of normal vein diameter 1

PE (70-80% ) – Post-thrombotic syndrome – Swelling in popliteal fossa

Longitudinal US Transverse US Color Doppler US




Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


Intimal dissection of abdominal aorta



Change in color coding due to

position of re-entry site

Color Doppler USLongitudinal & transverse scan

Gray-scale USLongitudinal & transverse scan

Intimal flap seen if sound beam

strikes at perpendicular angle

Search for involvement of visceral & iliac arteries




Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


Pseudo-aneurysm

Middleton WD et al. Ultrasound Quarterly 2005 ; 21 : 3 – 17.

To-and-fro flow

Typical triphasic flow

Pseudo-aneurysm / “to-and-fro” flow


During systole “to”

Flow enters PA via the neck

Pseudo-aneurysm lumen enlarges

During diastole “fro”

Flow exits PA via the neck

Pseudo-aneurysm lumen contracts

Pseudo-aneurysm / CFA2 – 4% of cases after catheter intervention

Large perivascular

fluid collection

Color Doppler: swirling pattern “yin-yang” pattern

Pulsed Doppler: “to-and-fro” flow classic pattern

Pseudoaneurysm / Variations in ‘‘to-and-fro’’ flow


Limited systolic flow More pronounced diastolic flow

Diastolic flow decreases progressively

Diastolic flow increases progressively

Diastolic flow relatively limited

Two distinct phases of diastolic flow

Variations in duration & velocities of systolic & diastolic flow due to arrhythmia

Pseudo-aneurysm / Multiloculated type Not uncommon


Mistake made by inexperienced examiners:

Recognize most superficial lobe correctly

Confuse deeper lobe with femoral artery

Pseudo-aneurysm / Differential diagnosis


Arborizing flow in enlarged inguinal LN mistaken for PS

Low-resistance arterial flow with continuous diastolic flow

Venous flow below baseline


Inguinal LN from melanoma

Vessels at base of LN different from pattern seen in PA

“to and fro’’ pattern near base of LN

Pseudo-aneurysm / Differential diagnosis

Pseudo-aneurysm / US-guided compression 3 steps

Franklin JA et al. J Am Coll Surg 2003 ; 197 : 293 – 301.

Preparation Compression Following repair

Duration of compression: 10 – 15 minutes

Success rate: 75 – 85%

Complications: PA rupture, distal embolization, & venous thrombosis

Pseudo-aneurysm / US-guided compression



Marked perivascular tissue

vibration associated with arterial jet

US guided

compression

Pseudoaneurysm

successfully thrombosed

ThrombosisPA of CFA

Pseudo-aneurysm / US-guided thrombin injection

Replaced compression as technique of choice

Needle advanced into superficial aspect of PA to avoid neck

100 – 300 units of human thrombin

Avoid fast injection

Success rate 97% according to several studies

Franklin JA et al. J Am Coll Surg 2003 ; 197 : 293 – 301.

Pseudo-aneurysm / US-guided thrombin injection

Second injectionComplete thrombosis

CFA pseudoaneurysmSurrounded by hematoma

Thrombin injectionunder US guidance



Success rate 97% according to several studies




Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


Arterio-venous fistulaLeft external iliac artery

Right external iliac artery

Low resistance arterial flow

Right external iliac vein

Arterialized venous flow

Left external iliac vein




Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


Arteritis / “macaroni or halo sign”

Higher-level echo

Lumen intima interface

Surrounded by

Concentric homogeneous hypoechoic structure

Intima media complex

Schäberle W. Ultrasonography in vascular diagnosis. Springer, Berlin, 2nd edition, 2011.

Transverse scan Longitudinal scan

Giant cell arteritis / Abdominal aorta“Macaroni sign”

Schäberle W. Ultrasonography in vascular diagnosis. Springer-Verlag, Berlin Heidelberg, 2nd edition, 2011.

Aortic wall thickening (typical finding)

IMA at its origin pierces thickened wall directly

without first coursing close to aortic wall as in fibrosis

Moussavian B & Horrow MM. Ultrasound Quarterly 2009 ; 25 : 89 – 91.

Retroperitoneal fibrosis / Ormond’s disease Hypoechoic cap-like structure anterior to aorta & IVC

Involvement of IVC important for differential diagnosis

Infra-renal abdominal aorta

Sagittal view

Infra-renal abdominal aorta & IVC

Transverse view

Retroperitoneal fibrosis / Ormond’s disease



IMA arising from left lateral aspect of aorta

Pushed against aortic wall before piercing hypoechoic layer

Aorta at origin of IMA

Inflammatory aortic aneurysmTypical appearance

Schäberle W. Ultrasonography in vascular diagnosis. Springer, Berlin, 2nd edition, 2011.

Atherosclerotic wall change

Circumferential hypoechoic layer around aneurysm confirms

the inflammatory origin of aneurysm

Transverse scan Longitudinal scan

Thrombangiitis obliterans / Buerger diseaseMale – Smoker – Young (34 years)

• Location Distal lower leg & foot

• Occlusion material Hypoechoic

• Vascular wall Hypoechoic without calcification

• Occlusion length alternating normal/abnormal seg

• Collaterals “corkscrew vessels”

• Vein Phlebitis migrans


Thrombangiitis obliterans / Buerger disease


37-year-old smoker – Rest pain in forefoot for 14 days

PTA

Occlusion without IMT Inflamed venous wall thickening

Superficial vein

35-year-old smoker – 3-year history of Buerger – Necrosis of toes

Typical corkscrew arteries

Buerger’s Disease / Corkscrew Collaterals

Fujii et Y. J Am Col Cardiol 2011 ; 57 : 2539.

Type I: Large snake sign

> 5 mm

Type II: Small snake sign

3 – 5 mm

Type IV: Small dot sign

< 1 mm

Type III: Dot sign

1 – 3 mm




Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


Vascular complications of entrapment syndrome

Post-stenotic aneurysm

Mural thrombi

Thrombotic occlusion

Method of choice for diagnosis & evaluation:

Duplex US with provocation tests



Popliteal entrapment syndrome / Provocation tests Examaging PA just below knee joint space

Plantar flexion of foot

against hand of examiner

Standing on tip toe

Stretching of knee

while patient lies prone


Popliteal artery entrapment syndrome (PAES)Plantar flexion test

Progressive compression of popliteal artery by GCM



Asymptomatic compression of PA by provocation tests in > 50%

Popliteal aretery entrapment syndrome (PAES)

Isolated popliteal artery occlusion

Transverse section

AS Soleus arteryVS Soleus vein

Longitudinal section

AS Soleus arteryVS Soleus vein






Aneurysm

Intimal dissection

Pseudo-aneurysm


Arteritis

Entrapment syndrome


Cystic adventitial disease of PACyst involving long popliteal segment

Transverse view Longitudinal view

Difficult to differentiate from dissection with thrombosis of false lumen



Cystic adventitial disease of PA

Transverse view Longitudinal view Pulsed Doppler



Doppler US of lower limb arteries






Bypass graft

Sonography is the recommended non-invasive

technique for the postoperative monitoring

of bypass graft patency

Types of graft

• Synthetic graft

PTFE* Above knee

• Autologous vein

Reversed vein Removal – reversal – anastomosis

In situ vein Leaves vein in its bed – anastomosis

In all cases Removal of valves in vein graft

Perforating veins tied off

* PTFE: Polytetrafluoroethylene

Aorto-bi-femoral graft Femoral-to-femoral artery bypass graft

Peripheral arterial bypass graft – 1

Peripheral arterial bypass graft – 2

Femoro-Popliteal Above Knee

Femoro-Popliteal Below Knee

Femoro-Tibial Below Knee

Bypass graft / Normal US

Composite PTFE & vein graft

Slightly dilated area

corresponding to valve site

In situ vein graft

Bypass graft / Normal flow pattern

Hyperemic flow often seen

in early postoperative period

Hyperemic monopahasic flow Pulsatile flow

Over time, flow normally

assumes a pulsatile flow

Bypass graft / Normal PSV

Average PSV

from 3 – 4 sites

without stenosis

Graft flow velocity

Normal PSV: 45 – 180 cm/s

AbuRahma AF et al. Noninvasive peripheral arterial diagnosis.

Springer-Verlag, London Limited, 1st edition, 2010.

Bypass graft / Causes of graft failure

Myers KA & Clough A. Making sense of vascular ultrasound. Arnold, London, 2004 .

Atherosclerosis

Graft degeneration

Neointimal hyperplasia

Technical faults

Bypass graft / Sampling velocities in stenosis

Ratio 2.0 = 50% stenosis

Ratio 4.0 = 75% stenosis

Proximal anastomotic stenosis

Graft conduit stenosis

Distal anastomotic stenosis

Bypass graft / Severe stenosis

Stenosis

PSV of A 16.4 cm/sec

PSV of B 319 cm/sec

Spectral broadening

B / A 19 times

A

Proximal to stenosis

A

B

At stenosis

B

Critical stenosis

Hemodynamic criteria & management of graft stenosis

Category

Risk PSVcm/sec

PSV ratio

Graftvelocity

Management

I Maximum > 300 > 3.5 < 45 AnticoagulationImmediate intervention

Wixon CL et al. J Vasc Surg 2000 ; 32 : 1 – 12.

II High > 300 > 3.5 > 45 Elective interventionin 15 days

III Moderate < 300 > 2 > 45 ObservationCorrection if progression

IV Low < 180 < 2 > 45 Observation

Bypass graft / Entrapment

Graft running between two

muscles causing moderate stenosis

Vein graft in lower tight

Graft compressed between two

muscles causing virtual occlusion

Leg flexion

Bypass graft / Occlusion

Extremely low volume flow recorded from in situ

vein graft indicates imminent graft occlusion

Bypass graft / Fibro-intimal hyperplasia

Large area of intimal hyperplasia in a vein graft

Bypass graft / Aneurysmal area in vein graft

Aneurysmal area in vein graft corresponding to valve site

Area of hyperplasia or thrombus in area of dilation

Bypass graft / False aneurysm

GFA

False aneurysm at distal end of femorofemoral graft

due to failure of anastomosis

Note corrugated appearance of Dacron material

Bypass graft / Seroma

Fluid-filled seroma

adjacent to vein graft

Differential diagnosis:

– Seroma

– Hematoma

– Lymphocele

– Abscess

Bypass graft / Infection

G

Echo region tracking from PTFE graft to skin surface

Pus discharging from skin surface at this point

I

G

I

PTFE (transverse view) PTFE (longitudinal view)

References

Arnold – 2004 Elsevier – 2005 Springer-Verlag – 2011

Thank You

Doppler ultrasound of lower limb arteries

Health & Medicine

Transcript of Doppler ultrasound of lower limb arteries