Vascular Imaging

Question 1

What is an ankle brachial index (ABI)?

Answer 1

a non-invasive measure of peripheral tissue perfusion used to rule out arterial disease

Question 2

How is an ABI performed?

Answer 2

In supine: Obtain brachial and ankle (highest of either the anterior tibialis or posterior tibialis arteries) systolic blood pressures

Then calculate the ratio of the BP of the LE compared with UE

Question 3

What is considered a significant difference between systolic BPs on an ABI?

Answer 3

more than 10 mmHg difference in R to L sides

Question 4

ABI = ____SBP/_____SBP

Answer 4

ankle

brachial

Question 5

ABI Interpretation:

__-__ = Vessel Calcification
__-__ = Normal
__-__ = Mild arterial insufficiency
__-__ = Moderate arterial insufficency, intermittent claudication
Less than __ = Severe arterial insufficiency and resting pain
Less than __ = Ischemic or gangrenous extremity and resting pain

Answer 5

1. 1 -1.3
2. 1 - 0.90
3. 9-0.70
4. 70-0.50
5. 5
6. 3

Question 6

Describe why the ABI may be misleading in patients with diabetes mellitus. What SBP should be used instead of the ankle BP in these patients?

Answer 6

Because they can have artificially elevated ankle pressures which underestimates the severity of the disease

Toe pressures

Question 7

What is the gold Standard for vascular evaluation?

Answer 7

Continuous Wave Doppler

Question 8

How is a continuous wave Doppler performed?

Answer 8

Cuffs are placed at the levels of the proximal & distal thigh, calf & ankle

Question 9

What is considered a significant finding on a continuous wave Doppler?

Answer 9

20 mmHg or greater reduction between segments of leg or between same levels of opposite leg

Question 10

What are the advantages of duplex scans?

Answer 10

• Provides accurate localization & quantification of lesions
• Differentiates stenosis from occlusions
• Provides precise answers about specific arterial segments
• Measures flow velocities in bypass grafts
• Can follow known lesions for evidence of progression
• Can monitor vascular reconstructions for development of stenosis

Question 11

What are the disadvantages of duplex scans?

Answer 11

• time consuming

- expertise needed

Question 12

What does transcutaneous O2 mapping do?

Answer 12

provides a measure of tissue hypoxia by looking at O2 tension of skin (mmHg) and can then provide a predictor of wound healing success or failure

Question 13

What does a laser Doppler measure?

Answer 13

skin perfusion during and after bypass procedures

Question 14

What is the advantage of performing a Magnetic Resonance Angiography (MRA)?

Answer 14

Measures LE ischemia in patients with a contraindication to standard contrast Angiography

Question 15

What is Computed Tomography Angiography used to detect?

Answer 15

clots in veins or narrowing/obstructions in arteries

Question 16

When is contrast angiography indicated?

Answer 16

In patients without contraindications to contrast medium who are about to undergo revascularization

Question 17

What can be defined as the time it takes for toe surface color to return to normal after removal of pressure?

Answer 17

capillary refill test

Question 18

What is normal capillary refill?

Answer 18

3 seconds or less

Question 19

What special test can help detect venous insufficiency but is not very sensitive or specific?

Answer 19

Homan’s sign