Duplex Scanning & Color Flow of the LE

Question 1

3 types of grafts on the lower extremities

Answer 1

1. synthetic graft
2. reversed saphenous vein graft
3. in situ vein graft

Question 2

stenosis PSV / prestenotic PSV

(2:1) ratio suggests

Answer 2

≥ 50% diameter reduction

Question 3

stenosis PSV / prestenotic PSV

(4:1) ratio suggests

Answer 3

≥ 75% diameter reduction

Question 4

lower extremity PSV greater or equal to 400 cm/sec suggests

Answer 4

≥ 75% diameter reduction

Question 5

common site of stenosis or occlusion in the lower extremities

Answer 5

level of the adductor (Hunter’s canal)

distal SFA, prox popliteal artery

Question 6

2 normal vein bypass graft findings

Answer 6

1. PSVs > 45 cm/sec
2. lower resistance flow in the distal graft outflow artery

Question 7

4 abnormal vein bypass graft findings

Answer 7

1. PSVs > 180 cm/sec
2. velocity ratio > 2.5
3. platelet/thrombus formation with PSV > 300 cm/sec
4. low PSV

Question 8

low PSV finding prompts for assessment of (2)

Answer 8

inflow disease
systemic cause

Question 9

when performing surveillance of LE vein bypass graft, consider revision if (4)

Answer 9

1. PSV > 200 cm/sec
2. intrastenotic to prestenotic systolic velocity ratio (SVR) > 3.0
3. high outflow resistance (no diastolic flow)
4. interval decrease in ABI > 0.2

Question 10

normal stented arteries will likely have elevated ___

Answer 10

PSVs

Question 11

greatly elevated PSVs suggest

Answer 11

stenosis ≥ 50% diameter reduction