Numbers to remember

Question 1

ABI

Answer 1

>1 normal
o   mild 0.7-0.9
o   Severe 0.5-.7
o   rest pain 0.3-0.5
o   critical ischemia <0.3

Question 2

Carotid stenosis <50

Answer 2

<125
(EDV <40)
<2

Question 3

Carotid stenosis 50-69

Answer 3

> 125
(EDV 40-100)
2-4

Question 4

Carotid stenosis 70- 89

Answer 4

> 230
(EDV >100)
4

Question 5

Carotid stenosis >90

Answer 5

> 400

>5

Question 6

Carotid stenosis near occlusion

Answer 6

High, low string flow

Variable

Question 7

St Marys index

Answer 7

ICA psv/CCA edv
<8 normal
8-13 50-69%
14-29 70-89%
>30 >90% but not near occlusion

Question 8

Leg arteries

Normal

Answer 8

<150cm/s

<1.5:1

Question 9

Leg arteries

30-49%

Answer 9

150-200

1.5:1) - (2:1

Question 10

Leg arteries

50-75%

Answer 10

200-400cm/s

2:1) - (4:1

Question 11

Leg arteries

>75%

Answer 11

> 400cm/s

>4:1

Question 12

Leg arteries

What are some extra things to remember about grading leg arteries?

Answer 12

PSV >220-250cm/s = significant
PSV >200cm/s has a high false positive rate
only lesions of greater than 50% are quantified and disease of less than 50% is given a more descriptive term using bmode and colour
A stenosis at the origin of a branching artery cannot strictly be graded using velocity ratios but absolute velocities have been applied with reasonable success

Question 13

Mesenteric

Answer 13

SMA >70% stenosis
PSV > 275 cm/s
EDV > 55cm/s
high resistance waveform
PSV > coeliac axis in the normal patient

Coeliac axis >70% stenosis
PSV > 200cm/s
EDV> 45 cm/s
Lower resistance waveform
PSV < SMA in the normal patient

Hepatic A
as per coeliac axis

Splenic A
as per coeliac axis. Note: Spectral waveform is often very turbulent.

IMA >50% stenosis
PSV > 200cm/s

Question 14

TIPS

Answer 14

the ends of the shunt in the native vessel at either end
good colour fill
low impedence waveform with some pulsatility acceptable
PSV 50-60cm/s (however baselines for patients are variable)
similar velocities at either end of the shunt
hepatopedal flow in the PV
Portal Vein > 30 cm/s (NR 37-47 cm/s)

Question 15

RAS native

Answer 15

Positive for stenosis direct assessment
renal artery: aorta (RAR) ratio > 3.5:1
PSV > 180cm/s
Suggests stenosis indirect assessment
pattern recognition: normal, equivocal, abnormal
loss of early systolic peak and flattening of the systolic upstroke is a marker for abnormality
resistive index: variation of > 0.05 (marker for abnormality)
resistive index: < 0.8 suitable for intervention

Question 16

RAS allograft

Answer 16

Positive for stenosis
Color aliasing at the stenotic segment
Distal turbulent flow
Peak systolic velocity > 250 cm/sec
Velocity gradient between the renal artery and external iliac artery greater than 1.8:1

Question 17

Venous incompetence

Answer 17

0.5s in the superficial veins

longer than 1.0s in the deep veins

Question 18

Perforator incompetence

Answer 18

An incompetent perforating vein displays >0.3sec of outflow from the deep to the superficial system.
Old criteria may include vein diameter of >3mm but this is unreliable.