Carotid Grading

Question 1

Critical stenosis is a (3)

Answer 1

Hemodynamically significant reduction in volume, pressure and flow

Question 2

What % of the cross-sectional area must be encroached upon before there’s a reduction in distal pressure & flow in the AORTA versus the carotid

Answer 2

Aorta: 90% reduction cross sectional area
Carotid: 70-90% reduction

Question 3

Plaque morphology: what does homogenous vs heterogenous vs calcified vs ulcerated suggest

Answer 3

Homogenous - acute
Heterogenous - longer
Calcified - chronic
Ulcerated - a piece broken off

Question 4

T/F - power Doppler does not show aliasing however it helps delineate low flow

Answer 4

True

Question 5

How do you adjust parameters to demonstrate low flow? (2)

Answer 5

Lower velocity scale & colour gain

Question 6

Stenosic zone SOUND

Answer 6

High pitched whistling (higher velocity)

Question 7

Post-stenotic turbulence SOUND

Answer 7

Garbled sound

Question 8

Distal stenosis SOUND

Answer 8

Low pitch, weaker amplitude

Question 9

Complete occlusion SOUND

Answer 9

Thumping

Question 10

What is the normal carotid intima media thickness (CMIT) measure?

Answer 10

<0.9 mm

Question 11

What do you document when a stenosis is found (4)

Answer 11

1- Proximal stenosis sample
2- Within stenosis: measure PSV & EDV (highest velocity recorded 2-3 times).
3- After stenosis: document post-stenotic turbulence
4- Distal tardus parvus waveform

Question 12

What is the PSV ratio measurement?
What does the ratio indicate as it increases?
When is this useful?

Answer 12

• PSV stenosis/PSV ICA
• The higher the ratio, the greater the stenosis (directly proportional relationship)
• Useful when velocities are globally low (i.e. decreased heart function)

Question 13

A MILD stenosis: ____% diameter reduction

Answer 13

Mild: 20% diameter reduction

Question 14

A MODERATE stenosis: ____% diameter reduction

Answer 14

MODERATE: 20-50% diameter reduction

Question 15

A MODERATELY SEVERE stenosis: ___% diameter reduction

Answer 15

MODERATELY SEVERE: 50-80%

Question 16

A SEVERE stenosis: ___% diameter reduction

Answer 16

SEVERE: >80% diameter reduction

Question 17

Total occlusion is

Answer 17

No residual lumen to measure

Question 18

Difference between calculating DIAMETER reduction vs. AREA reduction

Answer 18

Diameter:
longitudinal view + hemeodynamically significant lesions >50% diameter reduction

Area:
Transverse view + hemodynamically significant lesions >75% area reduction

Question 19

What is the FORMULA for calculating % stenosis for area/diameter reduction?

Answer 19

= 1 - (residual/original) * 100

Question 20

Systolic Acceleration Time (AT) or

RISE TIME is the

Answer 20

Onset of systole to peak systole (ms)

Question 21

The rise time in the renal arteries should be less than ____

Answer 21

70 ms

Question 22

NASCET Criteria:

<15% stenosis traits

Answer 22

Deceleration spectral broadening

< 125 cm/s PSV

Question 23

NASCET Criteria:

16-49% ICA Stenosis traits

Answer 23

Pansystolic spectral broadening

<125 cm/s PSV

Question 24

NASCET criteria:

50-69% stenosis

Answer 24

Pansystolic spectral broadening
PSV >125 cm/s
EDV <110 cm/s 
OR
ICA/CCA PSV ratio between 2-4

Question 25

NASCET criteria | 70-79% stenosis

Answer 25

``` Pansystolic spectral broadening PSV >270 cm/s OR EDV >110 cm/s OR ICA/CCA ratio >4 ```

Question 26

NASCET Criteria | 80-99% stenosis

Answer 26

EDV > 140 cm/s

Question 27

Patient HISTORY (6)

Answer 27

``` Previous stroke Smoker Elevated BP Hyperlipidemia Diabetic Family Hx of any above ```

Question 28

INDICATIONS (7)

Answer 28

``` Headaches Bruit Present stroke TIA Vertigo/dizziness A autos is fagax Limb weakness ```

Question 29

When are carotid BRUITS most COMMON? When are they most SEVERE?

Answer 29

Common: With increasing stenosis and maximal at 70-90% stenosis Severe: If pt has ipsilateral bruit, diabetes, or previous TIA

Question 30

*DIFFERENTIAL DIAGNOSIS of a carotid bruit (7)

Answer 30

- Murmur radiating from stenosis ao valve - ECA disease - Intraluminal turbulence ICA - Arteriovenous malformations - External compression from thoracic outlet syndrome - Scarring due to neck surgery - Tumour

Question 31

If the ICA/CCA ratio is 2 or more, then what 3 things occur?

Answer 31

There is a hemodynamically significant stenosis, meaning 1- the velocity doubles from CCA to ICA 2- the PSV of the ICA is > 125 cm/s 3- the ratio is 2 or more

Question 32

How do you measure the ICA/PSV ratio?

Answer 32

Proximal ICA PSV/Distal CCA PSV

Question 33

What is a CEA?

Answer 33

Carotid endarterectomy | A surgical procedure that removes plaque / blockage in lining of artery

Question 34

*When is a CEA recommended?

Answer 34

If the patient is symptomatic and >70% narrowing of artery

Question 35

How is calcified plaque delineated on the technical impression

Answer 35

Xxxxxx

Question 36

What is TRICKLE FLOW also referred to as?

Answer 36

Pre-occlusive flow

Question 37

With trickle flow, how would you adjust the parameters? (3)

Answer 37

Decrease PRF Increase colour gain Increase sample volume size to lumen width

Question 38

COLLATERAL flow examples (3)

Answer 38

1- OA direction in setting of high grade/complete occlusion of ICA 2- reversed VA flow and brachial artery systolic pressures in setting of SSS 3- Reversed ECA flow in setting of CCA occlusion

Question 39

Document changes in flow patters if the ICA is occluded (5)

Answer 39

1- Lower resistant with high flow “internalization” (because flow is now going into the ICA) 2- Post stenotic turbulence to stenosis (PST) 3- turbulent prox CCA flow in setting of INN A or LT SCA stenosis 4- Tardus parvus waveform distal to high grade stenosis 5- High resistant CCA prox to ICA stenosis

Question 40

When does externalization of the CCA happen?

Answer 40

Occlusion ICA, retrograde flow in stump of ICA, absence of flow in the ICA and beyond

Question 41

You should always include image of prox ICA demonstrating colour outline of _____ plaque

Answer 41

Soft plaque

Question 42

The term for a longer area of calcified plaque | How does this affect flow versus a shorter area of plaque?

Answer 42

Sessile

Question 43

Is angle correct necessary for the opthalmic artery?

Answer 43

No, only the direction of flow is important

Question 44

When do you use a straight colour box? (2)

Answer 44

Tortuous vessels | Imaging vessel in TRV

Question 45

POST STENOTIC TURBULENCE waveform

Answer 45

Loss of sharp upstroke Jagged peak Flow above and below the baseline simultaneously

Question 46

When you’re assessing OA, what parameters do you change? (2)

Answer 46

Lower PRF | Remove angle correct

Question 47

OA reversed flow suggests what (2)

Answer 47

ICA occluded or high grade stenosis | Normally ICA feeds the OA, but if it’s occluded, then ECA will feed OA

Question 48

What plaques are the most dangerous and why?

Answer 48

Hypo/echolucent - most likely to break off