Duplex / color Flow imaging (LE)

Question 1

Calcific shadowing

Answer 1

Limitations

Question 2

Df= 2 Fo V Cos 0
c

Answer 2

The Doppler equation

Question 3

Df

Answer 3

Doppler shift

Question 4

Fo

Answer 4

Carrier Frequency

Transducer frequency directly related to doppler frequency

Question 5

V

Answer 5

Velocity of moving reflectors

Question 6

Cos 0

Answer 6

Angle

Question 7

c

Answer 7

Speed of ultrasound through soft tissue

Question 8

Speed of ultrasound through soft tissue is

Answer 8

1540 m/sec

Question 9

The number is 2 represents

Answer 9

two Doppler shifts (in and out)

Question 10

Ideal Doppler angle for vascular exams is

Answer 10

60 degrees

Question 11

Not reliable Doppler angle is

Answer 11

> 60 degrees

Question 12

For native arteries you scan with what type of probe

Answer 12

7 - 5 MHz frequency linear array

Question 13

If a > 50% diameter reduction is suspected obtain

Answer 13

Pre- stenotic PSV

PSV (highest) in stenosis

Question 14

GSV - taken out

Small end is now Proximal

Large end is distal

Vein valves stay open due to arterial flow pressure

Branches are ligated (tributraies are cut off)

Answer 14

Reversed saphenous vein graft (RSVG)

Question 15

GSV stays in place

Small end is distal ‘

Large end is proximal

Prior to surgery, valves broken up with special instrument; branches ligated

Answer 15

In - situ Vein graft

Question 16

Inflow artery

Proximal anastomosis

Entire length of the vein bypass graft

Distal anastomosis

Outflow artery

Also check for branches (that could form AV fistulas), valves, and or other abnormalities

Answer 16

Vein bypass graft evaluation

Question 17

Inflow artery

Proximal anastomosis

mid graft

Distal anastomosis

Outflow artery

Answer 17

Synthetic bypass graft evaluation

Question 18

Doppler signals are triphasic

Some patients may have biphasic flow without any disease

Answer 18

Normal

Question 19

2:1 ratio =

Answer 19

> 50% diameter reduction

Question 20

4:1 ratio =

Answer 20

> 75% diameter reduction

Question 21

> 400 cm/sec PSV =

Answer 21

75 percent diameter reduction

Question 22

Pre - stenotic Doppler spectra

Answer 22

(monophasic) and dampened

Question 23

Doppler spectra obtained AT the stenosis

Answer 23

Highest PSVs documented

Question 24

Post stenotic turbulence and decreased PSVs

Answer 24

> 50% stenosis

Question 25

Lower resistance flow patterns may normally be expected. Some retrograde flow in the native artery may be evident at the distal anastomosis of RSVG, which proves and additional source of collateral flow. (retrograde flow results from a pressure gradient)

Answer 25

Normal

Question 26

Decrease in ABI of > 0.15 Observes for post-complications such as: AV fistula (can siphon off graft flow); valve cusp Insitu only- if tributary is not ligated

Answer 26

Abnormal findings

Question 27

Anastomosis sites should be evaluated well for aneurysm and/or stenosis Can loosely apply the previous data to determine whether a > 50% diameter reduction exists Observe for graft occlusions

Answer 27

Synthetic grafts

Question 28

In general velocities stented arteries may have elevated peak systolic velocities Greatly elevvated peak systolic velocities are abnormal and suggests hemodynamically significant diameter reduction

Answer 28

Post endovascular intervention

Question 29

Gray scale is most important Used for checking patency of the anastomotic sites Evaluate any suspicious stenotic or turbulent areas that can occur in vein bypass grafts Use highest frequency imaging transducer available

Answer 29

Intraoperative monitoring