The document discusses various imaging modalities used to evaluate peripheral arterial disease (PAD), including duplex ultrasonography, ankle brachial pressure index (ABPI) measurements, digital subtraction angiography (DSA), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). DSA is considered the gold standard but is invasive, while CTA and MRA provide non-invasive alternatives but have limitations such as exposure to radiation or contrast dye. Ultrasonography is useful first-line but not adequate for surgical planning. Overall, the optimal imaging choice depends on each patient's clinical situation and risk factors.

1. Dr amol gulhane
DNB resident
CARE hospitals , hyd

2. inner layer of endothelium (intima)
middle layer of connective tissue, smooth muscle and elastic
fibers (media)
outer layer of connective tissue (adventitia)
 have smooth muscles that contracts & relaxes to respond
changes in blood volume.

3.  charac. by a reduction in blood flow and hence 02 through
the peripheral vessels
 when the need of the tissues for 02 exceeds the supply, areas
of ischemia and necrosis will develop
Factors that can contribute to the development of peripheral
vascular disorders :
 atherosclerotic changes
 thrombus formation
 embolization
  coagulability of blood
 hypertension
 inflammatory process/infection

4. Atherosclerosis
Thrombosis or embolism
Aneurysm
Intimal dissection
Pseudo-aneurysm
Arterio-venous fistula
Arteritis
Entrapment syndrome
Cystic adventitial disease
Most common cause

5. Arterial Insufficiency
 there is a deceased blood flow toward the tissues, producing
ischemia
 pulses are usually diminished or absent
 sharp, stabbing pain occurs because of the ischemia,
particularly with activity
ischemic ulcers and changes in the skin.

6. 1. Age (elderly) – blood vessels become less elastic, become
thin walled and calcified –  PVR –  BP
2. Sex (male)
3. Cigarette smoking
› nicotine causes vasoconstriction and spasm of the
arteries –  circulation to the extremities
› C02 inhaled in cigarette smoke reduces 02 transport to
tissues
4. Hypertension – cause elastic tissues to be replaced by fibrous
collagen tissue  arterial wall become less distensible 
resistance to blood flow   BP
5. Hyperlipedimia – atherosclerotic plaque
6. Obesity – places added burden on the heart & blood vessels
› excess fat contribute to  venous congestion

7. 7. Lack of physical activity
› Physical activity – promotes muscle contraction 
 venous return to the heart
› aids in development of collateral circulation
8. Emotional stress – stimulates sympathetic N.S. - peripheral
vasoconstriction   BP
9. Diabetes mellitus – changes in glucose & fat metabolism
promote the atherosclerotic process
10. Family history of arthrosclerosis

8.  is a disorder in which there is an arteriosclerotic narrowing or
obstruction of the inner & middle layer of the artery
 most common cause of arterial obstructive disease in the
extremities
 the lower extremities are involved more than upper
extremities
 common site of disease – femoral artery, iliac arteries,
popliteal arteries
 in a diabetic, the disease becomes more progressive, affects
the smaller arteries and often involves vessels below the knee

10.  Sub-diaphragmatic aorta 21 – 24 mm
 Infra-diaphragmatic aorta 17 – 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

11.  Plaque formation on the intimal wall that causes partial or
complete occlusion
 Calcification of the medial layer and a gradual loss of
elasticity  weakens the arterial walls
 predisposes to aneurysm, dilation or thrombus formation

artery is unable to transport an adequate blood volume to
the tissues during exercise or rest

12.  Intermittent claudication – most common
› pain during exercise disappear w/in 1-2 mins. after stopping
the exercise or resting
› the femoral artery is often affected – pain in the calf muscle
– common symptom
 pain at rest is indicative of severe disease
› In advanced arteriosclerosis obliterans  ischemia may
lead to necrosis, ulceration and gangrene – toes and distal
foot

13. Stage Complains
I Asymptomatic
II a
II b
Mild claudication
Moderate to severe claudication
III Ishemic rest pain
IV Ulcer or gangrene
Clinical classification
The Rutherford classification

14. TASC II classification of femoral and popliteal lesions
type A lesions
single stenosis ≤ 10 cm in length
single occlusion ≤ 5 cm in length
type B lesions
multiple lesions (stenoses or occlusions), each ≤ 5 cm
single stenosis or occlusion ≤ 15 cm not involving the infrageniculate popliteal artery
type C lesions
multiple stenoses or occlusions totaling > 15 cm with or without heavy calcification
recurrent stenoses or occlusions that need treatment after two endovascular
interventions
type D lesions
chronic total occlusion of the common or superficial femoral artery (> 20 cm,
involving the popliteal artery)chronic total occlusion of the popliteal artery and
proximal trifurcation vessels

16.  Doppler ultrasonography –
› audible tone produced in proportion to blood velocity
› measure blood flow through vessels

17. Ankle brachial Pressure
The systolic pressure at any level of the lower extremity can be
measured by positioning a pneumatic cuff at the desired site.
Any patent artery distal to the cuff that is accessible to Doppler
ultrasound can be used for flow detection, but the posterior
tibial (PT) and dorsalis pedis (DP) arteries are usually most
convenient.
When the cuff is inflated to above systolic pressure, the
arterial flow signal disappears. As cuff pressure
is gradually lowered to slightly below systolic pressure, the flow signal
reappears,
and the pressure at which flow resumes is
recorded as the systolic pressure

18. In general, measurement of ankle systolic
pressure is the most valuable physiologic
test for assessing the arterial circulation in
the lower limb.
If the pressure measured by
a cuff placed just above the malleoli is less
than that of the upper arm, proximal occlusive
disease in the arteries to the lower limb
is invariably present.
The ratio of ankle systolic pressure
to brachial systolic pressure is called the
ankle-brachial index or ABI.

19. In the absence of proximal arterial occlusive
disease, the ankle-brachial index is
greater than 1 .0, (mean value of 1 . 1 1
± 0.10)
values greater than 0.90 are typically
interpreted as normal.
Usually limbs with single-level occlusions have
indexes greater than 0.5, and limbs with
lesions at multiple levels have indexes less
than 0.5
Many limbs with impending gangrene
or ischemic ulceration have absent Doppler
flow signals at the ankle level.

21. ABPI Comment
> 1.3 Falsely high value (suspicion of medial
sclerosis)
0.9 – 1.3 Normal finding0.75 – 0.9 Mild PAD
0.4 – 0.75 Moderate PAD
< 0.4 Severe PAD

22. 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

23. Narrow frequency band
Steep systolic increase
Quick drop
Early diastolic reverse flow
( of systolic flow amplitude)⅕
Late diastolic short forward flow

25.  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 disorders

26.  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

27. Normal triphasic waveform
Normal DPA at rest
Monophasic hyperemic flow
Following exercise

28. Monophasic waveform
Normal PSV
Normal rise time

29. Proximal to stenosis
The character of Doppler
signals obtained proximal to an arterial
obstruction depends on the capability of
the collateral circulation. If there are wel
ldeveloped
collaterals between the Doppler
probe and the point of obstruction, the
waveform may be relatively normal.

30. If the Doppler probe is placed directly over
a stenotic lesion, the signal has an
abnormally
high peak systolic frequency. This
reflects the increased flow velocity in the
stenotic segment.
At site of stenosis

31. When a waveform is obtained from an
arterial site distal to a stenosis or occlusion,
a single, forward velocity component is
observed, with flow remaining above the
zero baseline throughout the cardiac cycle.
The peak systolic frequency is lower than
normal, and the waveform becomes flat and
rounded
Distal to stenosis

32. High resistance, low volume waveform
Characteristic shoulder on systolic downstroke
Due to pulse wave reflection from distal disease
ShoulderShoulder

33. Tardus: Longer rise time
Parvus: Low PSV
Severe stenosis or occlusion
Tardus-Parvus waveformDamping waveform
Increased systolic rise time
Loss of pulsatility

34. IF superficial femoral artery is patent, a PI
less than 4 indicates a hemodynamically
significant aortoiliac lesion,
The PI of the normal
common femoral artery has a mean value of 6.7.
More distally, the PI increases to 8 in
the popliteal and 14 in the PT artery
A PI value greater than or equal to 4 is
predictive of a hemodynamically normal
aortoiliac segment.

35.  
Aorto-iliac: 25 %

Femoro-popliteal: 65%
Infra-popliteal: 10%

36. Proximal: 2 cm proximal to
stenosis
At stenosis : Same Doppler angle if
possible

37. Vr= psv ratio

38. SFA:
PSV of A 69 cm/sec
PSV of B 349 cm/sec
B / A 349 / 69 = 5
> 80% diameter
stenosis

39. 2 severe stenoses demonstrated in SFA
Areas of color flow disturbance & aliasing (arrows)

40. Drop-out of color flow signal in parts of lumen

41. Occlusion in CIA
Reversed flow in IIA (blue) to supply flow to EIA (red)

42. Ultrasound cannot provide reliable imaging if there are poor
acoustic windows (eg, bowel gas attenuation, diffuse vascular
calcification, or metallic stents) or poor intrinsic echogenicity
of the tissues.
Duplex scanning is time-consuming and
inconvenient post-operatively – when the region of interest
is obscured by dressings – and removing these can involve
infection risk.

43. DSA is the gold-standard for diagnostic imaging of PAD patients .
It enables large field-of view
(FOV) imaging with the highest possible in-plane resolution compared to other
modalities.
Drawbacks - catheterization,
nephrotoxic contrast,
exposure to high doses of ionizing radiation.
The procedure is associated with major risks such as
allergic reactions,
infections at the site of vascular access,
iatrogenic arteriovenous fistulas,
hematomas,
dissections.
Digital subtraction angiography (DSA)

44. Complications are reported to occur in 0.17-7% of procedures,
depending on the
arterial viability, the size of the catheter, the experience of the
clinician, and the location of the vascular access.
Given the invasiveness of the procedure, its applications is
now limited to
patients who require a surgical or percutaneous procedure for
therapeutic purposes
•DSA is the "gold standard" to diagnose, and
often to treat vascular disease. It involves
getting detailed x-ray images of the arteries
while injecting dye directly into the arteries. For
patients with poor kidney function, a non-toxic
gas carbon dioxide can be used in place of IV
dye. Blockages can often be opened minimally
invasively during an angiogram.

45. LEFT CIA STENOSIS

46. A) A catheter has been passed from the right common femoral artery and into the
abdominal aorta during a digital subtraction
angiogram. Contrast injection through the catheter reveals minor atherosclerotic wall
abnormalities in the infrarenal aorta and the left common femoral artery
B) Lower limb images reveal diffuse atherosclerotic disease of the superfi cial femoral
and popliteal arteries of both sides, with a focal area of significant stenosis in
the right popliteal artery.

47. CT Angiography (CTA)
CTA enables visualization of the entire peripheral vascular
tree and offers information about
lesion length, diameter, and morphology, as well as degree
of calcification, and status of distal
runoff vessels.
A number of studies have compared CTA
to the gold-standard
DSA, showing comparable diagnostic
accuracy and high confidence in
clinical decision-making solely based on
CTA .

48. CTA offers evaluation of plaque, calcification, and
vascular wall, while DSA
depicts only arterial lumen.
Technical limitations ---- inability to
characterize calcified lesions, particularly in smaller
vessels, due to
beam-hardening artifacts.
Drawbacks –
radiation doze
nephrotoxicity of contrast, which
is contraindicated in patients with
decreased renal function and renal
insufficiency.

49. CTA image of the iliofemoral arteries.
Severe, focal stenosis (arrow) is present in
the right mid-to-distal superficial femoral
artery

50. MR Angiography (MRA)
CE-MRA is similar in set-up and diagnostic quality to CTA.
CE-MRA methods rely on an injection of contrast material,
which alters the magnetic
properties of blood.
Peripheral MRA is routinely performed with gadolinium
(Gd)-based contrast agents .
As vascular contrast is
relatively independent of flow-dynamics, CE-MRA can be used for large field-of-view
(FOV) imaging.

51. For assessment of hemodynamically significant
disease Gd-MRA has reported sensitivities of 89-99.5% and specificities of 95-99%
compared to DSA.
Advantages of CE-MRA over CTA === no ionizing radiation
ability to depict
lumen of calcified vessels.
Limitations == cost,
scan time
metal artifacts from stents and surgical clips.
Association between nephrogenic systemic fibrosis and gadolinium
contrast has limited the applicability of CE-MRA in kidney disease patients.

52. Among the imaging modalities used in PAD evaluation, usg has
no contraindications for patient with renal insufficiency.
Ultrasonography alone is
inadequate for planning of surgical procedures because it does
not provide accurate visualization
of the entire peripheral vascular tree.
Among the remaining modalities, both DSA and CTA,
given their exposure to nephrotoxic contrast material and ionizing
radiation, are unsafe for kidney disease patients.
Recent association between nephrogenic systemic
fibrosis and gadolinium contrast has challenged the safety of CE-
MRA as well

53. Contrastenhanced
peripheral
MRA

54. Symptomatic iliac artery occlusive disease, diagnosed with gadolinium-enhanced MR
angiography. (a) Coronal MIP image from a gadolinium-enhanced 3D MR angiographic
study performed with administration of gadopentetate dimeglumine demonstrates bilateral
severe proximal iliac artery stenoses, with the right greater thanthe left (arrows).
(b) The next anatomic station was imaged 10 minutes after the preceding study with a
second dose of gadopentetate Dimeglumine by using a slightly faster sequence. There is

55. Unlike DU, MRA
allows simultaneous angiographic as well as anatomical
volume acquisition of the whole body in seconds whilst
maintaining high spatial resolution.
This allows both luminal
and extra-luminal pathology to be shown simultaneously,
although magnetic resonance imaging is poorer for bony
anatomy than computed tomography

56. Like DSA, contrast enhanced magnetic resonance imaging is
sensitive to patient motion artefacts. If there is patient motion
between the mask acquisition and postcontrast acquisition,
there will be image degradation following subtraction.
Magnetic resonance cannot image calcification or steel
stents; causes susceptibility artefacts
recognizable as signal voids in the image.
Metallic structures
within the vessel lumen or adjacent to the vessel may cause
magnetic susceptibility artefacts that obscure the vessel lumen
leading to a false diagnosis of a stenosis or obstruction.

57. Non-Contrast Magnetic Resonance
Techniques for Peripheral Angiography
In recent years there has been a renewed interest in unenhanced
techniques, determined by two major factors.
(1) improvements in MRI hardware and software have
reduced acquisition times and made non-contrast imaging clinically
practical
(2) concerns about NSF in advanced renal disease patients

58. Non-contrast MRA techniques rely on flow-induced
changes in the longitudinal or
transverse magnetization of blood to obtain contrast
between the vasculature and stationary
background without administration of exogenous contrast
material.
Four major approaches for
artery-background contrast generation exist:
(1) Time-of-flight techniques (TOF) rely on differences in exposure
to radiofrequency
excitation between stationary tissue within the volume of interest and
blood protons
flowing into the imaging slab from outside the FOV.

59. (2) Phase-contrast MRA relays on measurable velocity-
induced changes in the phase of
the blood signal
(3) ECG-triggered subtraction techniques relay on the
difference in arterial flow velocity
between systole and diastole; either gradient echo or fast
spin-echo read out can be
used
(4) Flow-independent angiography uses an acquisition
that naturally provides bright blood
signal weighting, combined with inversion-recovery and T2
preparation to null
the signal of background tissues.

60. Currently, the MR angiographic approach
to the tibial vessels is dominated
by the use of TOF techniques
This flow-dependent strategy circumvents
the challenge of achieving a sufficient
concentration of contrast medium
to effectively demonstrate the distal arterial
Vessels.
At present, TOF imaging
offers the surgeon sufficient information
to make the primary surgical decisions

61. Overestimation of segmental occlusions with TOF imaging. (a) Coronal MIP image
obtained with TOF imaging demonstrates bilateral iliac artery occlusions, with right
greater than left.
(b) MIP image from a gd-enhanced 3D MR angiogram shows a shorter length of
each occlusion compared with a.
The depiction of the right hypogastric artery which was not seen with TOF imaging.
Suppression of thesignal from retrograde flow is a major limitation of TOF strategies
designed to eliminate venous
signal.

62. Vascular calcifications in a patient with diabetes mellitus. A, Coronal thin
section maximum intensity projection (MIP) of a computed tomography
angiography of the tibial peroneal runoff vessels demonstrating how dense
calcifications in this patient population obscures analysis of the lumen.
B, Contrast-enhanced magnetic resonance angiography is insensitive to
vascular calcification as well as bone, simplifying image interpretation as
demonstrated in this full-volume MIP from the same patient as in A.

64. – directed toward prevention of vessel occlusion
 use of vasodilators
Surgical intervention – in advanced disease – ischemic changes
and pain severely impairs activity
 Embolectomy
› removal of a blood clot, done when large arteries are
obstructed
 Endarterectomy
› is removal of a blood clot and stripping of atherosclerotic
plaque along with the inner arterial wall.
 Arterial by-pass surgery
› an obstructed arterial segment may be bypassed by
using a prosthetic material (Teflon) or the pt’s. own artery
or vein (saphenous vein)

65. Primary treatment strategy according
TASC severity
TASC A - endovascular therapy
TASC B - endovascular therapy
TASC C - surgical therapy (if patient is able
to be operated, otherwise endovascular
therapy)
TASC D - surgical therapy

66. Endarterectomy

70.  Percutaneous Transluminal Angioplasty
› The balloon tip of the catheter is inflated to provide
compression of the plaque
 Amputation
› with advanced atherosclerosis & gangrene of extremities
› toes are the most often amputated part of the body

71. FA lumen filled with hypoechoic thrombus or embolus
Good delineation of vessel wall without signs of plaque
Normal flow in adjacent FV
.

72. 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
Considerable variability in normal diameter of
arteries
Depends on physical size, sex, & age
.

73. True aneurysm
False aneurysm
Dissecting aneurysm

74. .

75. Sonography is the recommended non-
invasive
technique for the postoperative
monitoring
of bypass graft patency
Sonography is the recommended non-
invasive
technique for the postoperative
monitoring
of bypass graft patency

76.  Synthetic graft
PTFE* Above knee
 Autologous vein
* PTFE: Polytetrafluoroethylene

77. Aorto-bi-femoral graft Femoral-to-femoral artery bypass graft
Peripheral arterial bypass graft – 1

78. Femoro-Popliteal
Above Knee
Femoro-Popliteal
Below Knee
Femoro-Tibial
Below Knee

79. Composite PTFE & vein graft
Slightly dilated area
corresponding to valve site
In situ vein graft

80. Hyperemic flow often seen
in early postoperative period
Hyperemic monopahasic flow Pulsatile flow
Over time, flow normally
assumes a pulsatile flow

81. Average PSV
from 3 – 4 sites
without stenosis
Graft flow velocity
Normal PSV: 45 – 180 cm/s

82. 
Atherosclerosis
 Graft
degeneration

Neointimal
hyperplasia
 Technical
faults