Module 5

Question 1

what arteries are routinely scanned with a carotid US

Answer 1

Common carotid (CCA)

Internal carotid (ICA)

External carotid (ECA)

Vertebral (VA)

Question 2

patient prep for carotid US

Answer 2

Document history and risk factors

Explain the procedure to the patient

Position patient in the supine position

Head turned slightly away from side being examined

Question 3

what kind of waveform is the CCA

Answer 3

low resistive wave form and is always positive (above the baseline) as the blood flow to the brain needs to be constant

Question 4

what kind of waveform is the ECA

Answer 4

higher resistive waveform as supplying the face which has many small high resistive vessels

Question 5

what are 3 indications of a stenosis

Answer 5

If narrowing >50% will produce an increased velocity of blood flow in both PSV and EDV

Aliasing

Spectral broadening

Question 6

what are the 7 characteristics of normal veins

Answer 6

Compressibility

Vein size (larger than arteries)

Spontaneous flow (flow at rest)

Phasic flow (flow changes with respiration)

Augmentable flow (calf squeeze)

Valsalva response

Unidirectional flow

Question 7

prep for lower limb US

Answer 7

No specific prior preparation is required for a DVT scan

The legs need to be made accessible

Obtain a thorough clinical history –

Question 8

how to determine if thrombus is present

Answer 8

Echogenic material is visualized within the vein

vein will not compress

Question 9

lower leg pathology

Answer 9

Thrombi

Thromboembolism

Question 10

sonographic appearance of acute thrombus

Answer 10

Hypoechoic (almost invisible)

Poorly attached to the vein wall

Spongy

Dilating the vein wall (if the vein is totally obstructed)

Question 11

sonographic appearance of chronic thrombus

Answer 11

Appear more echogenic and heterogeneous

Be adherent to the vein wall
Contract the vein wall over time (if the vein is totally obstructed)

May be accompanied by large collateral veins nearby

Question 12

what does it mean if the spectral window is filled?

Answer 12

it is not centred in the middle of the vessel or that there is pathology (stenosis)

Question 13

where does plaque usually form within the CCA

Answer 13

underneath intima layer (bubbling of this layer indicates plaque formation)

Question 14

how do we differentiate ECA and ICA

Answer 14

ECA has branches and has a high resistive waveform and responds to temporal tap

ICA has no branches and has a low resistive waveform

Question 15

what is phasicity and what does it tell us

Answer 15

the velocity should change during respiration; if not, there is a problem

Question 16

what is augmentation and what can it tell us

Answer 16

Sample in vessel and listen to it; Phasicity would tell us there is no clot above

To exclude clot distally, we would squeeze distally to push blood through vessel in a short sharp way –> velocity increases, and then returns to normal

If this works, it is highly unlikley there is a thrombus distally