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So here's an example of near occlusion to occlusion of the left common

0:06

carotid artery. So this is not an ICA problem, this is a common carotid artery

0:11

problem. You can see even on the grayscale images here, you can see a normal

0:16

anechoic or dark lumen here, and then as we go a little bit more cranial, you can

0:20

start to see there's echogenic material filling the lumen there.

0:25

And when we add the color Doppler, you can see essentially we have flow up to a

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point, and then flow is not really persisting beyond that area.

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When we try to get a true spectral Doppler waveform here, we essentially get a

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waveform that is really not telling us a whole lot. It's just small little areas.

0:45

It's consistent, so we can see that there is flow here, but this is creating what

0:50

we would call a string sign. The velocity is much, much less.

0:53

The compensation mechanisms have now run their course, and this is no longer able

0:58

to increase velocity to compensate for it.

1:00

It's also basically hitting a brick wall, essentially, as it tries to perfuse

1:04

beyond this portion. And so this was consistent with a pretty significant carotid

1:09

stenosis, and then progressing to occlusion.

1:13

We can see similar findings here in the distal CCA.

1:16

You can see the lumen is completely filled with echogenic material.

1:20

As we put a color Doppler and then a spectral Doppler on that area, you can see

1:24

it's not uncommon that we will see some areas of recanalized flow, but this is not

1:29

really consistent. And so when we actually try to get flow outside of that, again,

1:33

there's complete occlusion in that area.

1:37

We do complete the exam just to show the areas, but the bulb is

1:43

also occluded. And then when we try to get up into the ICA, again,

1:49

also occluded. So this patient had essentially carotid occlusion from the proximal

1:53

portion all the way up through the ICA.