0:00

The next case that we're going to look at is a case of an arteriovenous

0:04

malformation. So as I'm scrolling down in this

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38-year-old male with arterial phase images, we're going to

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focus first on the right lower extremity.

0:17

And again, we're looking at both the deep arterial and venous

0:21

system, as well as the superficial plane.

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And we start noticing a tangle of vessels along the

0:28

medial aspect of the distal thigh right here,

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and then this tangle of veins kind of...

0:37

Or this tangle of vessels kind of continues along that medial aspect of the

0:40

knee. And then there's another little nidus that's there in

0:44

this proximal calf right here.

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Now, all of these are showing an early filling and

0:51

typically we have superficial veins that harbor here.

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And so,

0:58

we need to look for an arteriovenous malformation, given that there's

1:01

early enhancement of the veins. The veins are dilated.

1:05

The superficial veins are dilated.

1:06

There are areas of calcification, and there are

1:10

nidus-like areas that are seen.

1:13

So once we try to look at the feeding vessels, we are

1:17

really going to pay attention and look at any vascular branches that are

1:21

coming off and are supplying these niduses.

1:25

So we're going to start focusing on our popliteal artery

1:29

here as we're coming down, and we're going to look at all the vessel

1:32

branches, such as this one that goes from the popliteal

1:36

artery right here,

1:38

and then it goes right here, and you can see that this vessel

1:42

loops

1:45

and meets this enlarged vascular

1:48

structure right here, which then forms the nidus.

1:51

So this

1:53

is probably one of the feeders, arterial feeders of

1:57

this arteriovenous malformation.

2:01

Looking at the venous drainage now.

2:02

Venous drains, the veins are obviously dilated

2:06

because of the shunting in this person.

2:09

And we need to look at

2:11

the veins that are draining this nidus

2:15

as well. So,

2:17

over here we can, as we're kind of scrolling down and

2:21

looking at the veins, there's a really enlarged anterior tibial vein.

2:24

And you can see that this vessel kind of goes and

2:28

drains into here. So they're definitely feeding veins into the anterior

2:32

tibial vein,

2:34

as well as into the posterior tibial veins right

2:38

here, which are enlarged, and they feed into it.

2:42

So we have large niduses of arteriovenous malformations in

2:45

that right lower extremity.

2:49

I know there's also a left lower extremity here, and it's not the

2:53

focus of our attention today, but just to complete out

2:57

our thought process here, when we named everything in that right lower extremity

3:01

and that left lower extremity, the arteries are enlarging,

3:05

are patent and are showing opacification.

3:08

But there is no enhancement of these dilated structures in the

3:12

superficial vein. One of them shows a calcification and is a superficial vein,

3:17

as is the one that's at the back here.

3:20

On the delayed phase, however, this does show opacification.

3:24

So these are actually venous aneurysms.

3:27

They're unlikely to have an arterial communication considering they did not

3:31

opacify on the arterial phase. So,

3:34

CT can be quite dynamic. We've seen cases now where it

3:38

suggested sluggish flow to an extremity.

3:40

It shows what the branches are, whether it's

3:44

opacifying, like an artery or a vein.

3:46

And that's why it's supplanted and is by far a superior

3:50

imaging modality to assess the lower extremities.