This document discusses screening methods and techniques for examining the peripheral arteries using ultrasound, including Doppler frequencies above 3 MHz, real-time gray-scale sonography to evaluate plaque, and color flow Doppler to rapidly survey arteries and detect stenoses. Compared to angiography, ultrasound has advantages of being noninvasive, inexpensive, and allowing for serial exams. Techniques discussed include gray scale imaging, duplex Doppler sonography, color Doppler sonography, and power Doppler. The document also covers Doppler flow patterns, arterial aneurysms, stenoses and occlusions, vascular grafts, dialysis access grafts, and evaluating masses.

1. The Peripheral Arteries
Prepared by Dr Vrishit Saraswat
Guided my Prof. Dr Dharmraj Meena

2. Screening Methods
• The upper and lower extremity arteries , easy to
examine, becoz of good imaging window.
• Doppler frequencies are typically more than 3 MHz.
• Though real-time gray-scale sonography is useful for
evaluating the presence of atherosclerotic plaque or
confirming the presence of extravascular masses. Color
flow Doppler sonographic imaging allows the clinician
to survey the area of interest rapidly, determine if
vascular structures are present, and if so, characterize
their blood flow patterns

3. Compared with duplex sonography (spectral
Doppler and gray-scale sonography) alone, color
flow Doppler imaging can more rapidly survey the
full lengthof limb arteries and detect the
presence of significant stenoses and occlusions.
• Compared with angiography, US CD has
advantage of being noninvasive, relatively
inexpensive, and well suited for serial
examinations.also in pts with poor renal
functions.

4. Techniques
1. Real time Gray scale imaging
2. Duplex Doppler Sonography
3. Colour Doppler sonography
4. Power doppler sonography

5. • Power Doppler- No Aliasing, signal strength
are much less angle dependant and slowly
moving blood is more easily detected.
• The main attraction of power doppler is that it
is a sensitive technique, good for depicting
flow in small vessels and give more complete
images of vascularity.

6. Doppler flow Patterns
• Normal Arteries show Triphasic pattern.
1. Strong forward component during systole
2. Short reversal during early diastole.
3. Low amplitude forward flow.

9. • Stenotic Arteries
Distal to stenosis- low resistant pattern, bcoz of
opening of collateral branches n loss of
normal arterial tone.
At Stenotic site- High Velocity flow, proportional
to stenosis.ON CD, shown as aliasing.

12. A-V Fistulas
• Two types
1. Congenital- located just below skin, avident
clinically and on CD visualized as distended
venous channel with single of multiple
arterial feeding branches. ***Smaller non
distended veins which hv not dilated yet, may
show increase blood flow signals.

13. 2. Iatrogenic-post arterial or venous
catheterization , or other penetrating
traumas. Jet of blood flow seen
(communication). Jet has high velocity
signals, imapct of blood on venous walls
causes vibration which are seen as artefacts
on CD.
DD- compression of vein by hematoma.

16. Masses
• DD of perivascular masses is facilitated by use
of color doppler flow imaging.
• Blood flow signal contiguous to an artery
suggest the diagnosis of peudoaneurysm(PA)
• PA can be a sequelae of either post vein
grafting , where the neck of aneurism is broad
; iatrogenic, ex- after Cardiac Sx, where small
channel communicates to larger , containing
blood.Radial Art most commonly involved.

17. • On CD PA shows
1. Colour Yin-Yang sign-typical swirling motion
with in collection.
2. TO and Fro pattern of blood flow
corresponding to systole and diastole.

22. • Another DD is Hyperplastic LN- here CD image
may mimic PA but there absense of to and fro
pattern & detection of arterial as well as
venous signals.
• Tumors on the other hand show ring of
hypervascularity at their periphery.Arterial
aneurysms tend to be confined with the
arterial walls.

23. Aneurysms-Diagnostic criteria
• Focal enlargement
• Mc location- popliteal or distal sup femoral
• Often B/L
• Remain asymptomatic for long time.
• 2cm cut off criteria of focal dilatation.
• OR a buldge or focal enlargement of 20% of
expected vessel diameter.
• Association- TOS-> Aneurysm->emboli->digit

24. • ***US can detect aneurysm and thrombosis ,
angiography sometimes appears normal if
thrombus present in dilated segment

28. Stenoses & occlusion-diag. criteria
• If PSV more than doubles from normal
segment- >50% narrowing
• Sometimes due to peripheral vasocontriction
distal to occlusion, the wave form shows
monophasic high resistence flow of duplex
doppler. BUT , PSV is less sensitive to
vasoconstriction or dilatation, so is preffered
parameter
• PSV >200 or 300 = severe stenosis.

29. • Mild stenosis – 10- 19 % stenosis. Normal
waveform, PSV 30% greater than proximal normal
segment.
• Moderate stenosis- 20-49% triphasic waveform,
PSV 100% greater than proximal segment.
• Severe Stenosis- >50%,PSV doubles the proximal
segment. High resistance monophasic flow with
loss of diastolic reversal.

33. Synthetic Vascular Bypass Grafts
• Various complications can arise
• Early failures-1-2 yr after Sx b/c of technical
errors
• Late failures-5-10 yr after SX, b/c of
progression of atherosclerotic lesion in native
vessel. Pseudoaneuryms may also develop.

35. Dialysis access Graft
• Typically created b/w Radial art and cephalic vein.
• 3 types –
Brescia-Cimino Loop Straight
(graft) (graft)
Aneurysm & stenosis( S/E)

36. • The vein being accessed needs to be close
enough to skin
• Kinks , stenosis need to be ruled out & collateral
pathways need to be mentioned.
• Aneurysm and stenosis are common problems
after fistula formations, msotly with alternative
type of dialysis access(i.e. with grafts)
• Graft thrombosis is ultimately is source of graft
rejection.

37. • PSV of arterialized vein tends to be
higher(100-200cm/s) for first few months, so ,
if any stenosis occurs , will be difficult to
diagnose.

38. Normal arterial inflow into a dialysis
graft placed in the
groin.

39. Doppler waveform obtained in the graft proper
with velocities of approximately 200 cm/sec

40. Doppler waveform
at venous outflow shows normal, persistent evidence of
turbulence.