1. Vascular p142-145 (Carotid Doppler)

Question 1

Carotid stenosis - imaging criteria (4)

Answer 1

Normal:
- ICA PSV (peak systolic velocity) <125cm/s
- ICA/CCA PSV ratio <2
- ICA EDV (End diastolic velocity) <40cm/s
<50% stenosis
- Will not alter PSV.
50-69% stenosis
- ICA PSV 125-230cm/s
- ICA/CCA PSV ratio 2-4,
- ICA EDV 40-100cm/s
>70% stenosis
- ICA PSV >230cm/s
- ICA/CCA PSC Ratio >4
- ECA EDV >100cm/s

Question 2

Proximal stenosis - imaging (3)

Answer 2

Tardus parvus waveform
- unilateral - stenosis of innominate artery
- bilateral - aortic stenosis

Question 3

Subclavian steal - imaging (4)

Answer 3

Stenosis or occlusion of the proximal subclavian artery with retrograde flow in ipsilateral vertebral artery
Imaging
- Retrograde flow in left vertebral
- Stenosis of subclavian with high velocity
Early steal
- Steal starts with mid-systolic deceleration with antegrade late systolic velocities.

Question 4

Internal vs External carotid - doppler (4)

Answer 4

Low resistance vs High resistance
Low systolic velocity vs High systolic velocity.
Diastolic does not return to baseline (brain is always on) vs diastolic approaches zero at baseline
Continuous flow during cardiac cycle vs intermittent flow

Question 5

Temporal tap (2)

Answer 5

Tap temporal artery on forehead and look for ripples in the spectrum to look for external carotid.
Can also look for branches to tell external from internal carotid.

Question 6

Aortic regurg - imaging

Answer 6

Bilateral CCAs with reversal of diastolic flow

Question 7

Brain death - imaging

Answer 7

Loss of diastolic flow in ICA suggests cessation of cerebral blood flow

Question 8

Aneurysms - imaging

Answer 8

Distal formation of an aneurysm (i.e. in the skull) cannot be detected by ultrasound. proximal flow is normal

Question 9

Intra-aortic balloon pump - features and imaging (5)

Answer 9

Superior balloon 2cm distal to origin of left SCA.
Inferior balloon just above renal arteries.
When balloon inflates, it displaces blood in that section of the aorta superiorly and inferiorly.
Balloon inflates during early diastole (after aortic valve closes), when maximal blood is available for displacement.
Will cause an extra bump in ICA waveform. measure first bump as this is unassisted.

Question 10

Normal carotid doppler appearances (3)

Answer 10

Normal CCA:
- peak velocity 60-100cm/s
- continuous diastolic flow
Normal ICA:
- lower peak velocity
- higher velocity continuous diastolic flow
Normal ECA:
- Higher peak velocity.
- Less diastolic flow

Question 11

ICA occlusion - doppler appearance

Answer 11

CCA looks like ECA, with high resistance waveform and loss of diastolic flow

Question 12

Aortic regurg - doppler appearance (2)

Answer 12

Either:
- Classic reversal of diastolic flow, usually shown bilaterally
- OR
- Pulsus Bisferens/double systolic peak (also seen in severe COPD)

Question 13

Aortic stenosis - doppler appearance

Answer 13

Bilateral tardus parvus waveform

Question 14

Dissection - doppler appearance

Answer 14

Not really doppler but will can see dissection flap on USS