0:00

The next scan and the last one in the series of peripheral arterial

0:04

disease is a peripheral artery aneurysm.

0:07

We discussed how the most common aneurysm in the peripheral

0:11

arteries is, in fact, the popliteal artery aneurysm.

0:13

But because we have all the data set, these patients also can

0:17

have aneurysms in their visceral arteries.

0:20

We're going to do a dedicated

0:22

assessment of the artery that is in question here.

0:26

So as we're scrolling, we can see that there's aneurysmal dilatation of the

0:30

common iliac arteries on both sides.

0:32

In an ideal scenario, we don't just measure on a true

0:36

axial plane, the measurement of an aneurysm like this.

0:40

We do a double oblique measurement for any

0:43

time in the vascular world when we try to measure something, which means that we're

0:47

going to go

0:49

on our multiplanar reconstruction view.

0:51

We're going to make sure that we line up our crosshairs on both the

0:55

planes, and then we're going to take out our calipers as we have a

0:59

true double oblique along across that structure, and

1:03

we're going to give an accurate measurement.

1:05

So here, that aneurysmal left common iliac artery measures

1:08

2.8 centimeters by 2.3 centimeters.

1:13

So as we're kind of going down, that's exactly what we're going to do.

1:17

There's also an aneurysmal dilatation of the right

1:21

internal iliac artery right here.

1:24

We're going to scroll down all the way, looking at both the

1:29

superficial femoral arteries. There's plaque everywhere, some

1:32

stents, mild stenosis. And you can really

1:36

see that degree of opacification is much lower here,

1:40

even though it's an arterial phase image compared to all the other scans we've seen

1:44

thus far. And as we're going down, there's obviously this

1:47

enlarged aneurysmal sac along the popliteal artery

1:51

on the left side, as well as on the right side.

1:54

And a lot of it doesn't enhance, suggesting that there is mural thrombus in the

1:58

popliteal artery. Now, we discussed the concept of

2:01

outrunning of a bolus when we were doing our technique section.

2:06

We discussed how it can be because the table moves too fast, it's accentuated when

2:10

the patient has low cardiac output.

2:12

This is another setting where this becomes important.

2:15

So we have a second series here, which is the immediate delay, and as I've popped

2:19

this over here, you can see how much brighter that contrast got

2:22

and how much nicer you can see the opacified lumen compared to that

2:26

mural thrombus in that aneurysmal sac on both sides.

2:31

So we're going to scroll down, and there's bilateral popliteal artery aneurysms.

2:35

Again, when we are measuring, we are going to measure in a

2:39

double oblique fashion, which means get our crosshairs on and measure it at its

2:43

largest, go double oblique at its widest point,

2:47

describe the morphology, so if it's bilobed, the length of

2:50

involvement, because all of this plays a role in management.

2:54

We've learned that if it measures more than two centimeters in

2:57

size,

2:59

then we have to intervene on them. If there is mural thrombus, there is

3:03

a higher rate of growth of the aneurysm sac.

3:07

So these, of course, meet that surgical criteria.

3:10

This one is a bilobed one on the left side.

3:12

So you see that there's an aneurysm with thrombus in this coronal

3:17

view.

3:18

And then you have the small intervening segment, which is not as aneurysmal, and

3:22

then you have another one. So kind of bilobed fusiform

3:25

aneurysmal dilatation of the popliteal artery also on the left side

3:29

with this large amount of mural thrombus

3:33

associated, and it's 4.2 centimeters by 3.8

3:37

centimeters on the left.

3:40

Sometimes we can even see distal emboli or...

3:43

But it can be difficult because obviously these patients

3:47

can have coexisting peripheral arterial disease,

3:51

so there's a lot of calcifications in the renal

3:55

vessel

3:56

on both sides as well, and

4:00

kind of assessment of the entire vascular tree then becomes important.

4:06

Coming to peripheral aneurysms. So we call

4:10

something a peripheral aneurysm when it's dilated by more than

4:13

50% greater than normal.

4:16

Now, a normal popliteal artery can have a varying range.

4:18

It can go all the way from five to 10 millimeter.

4:21

And so really, we kind of keep a watchful eye on them.

4:25

When they're incidentally found, we want to screen that contralateral leg and the

4:28

abdominal aorta. When they're large,

4:32

they can be an indication for repair.

4:34

So if they're symptomatic or if their size is more than two centimeter, they might

4:38

consider repairing a popliteal artery aneurysm.

4:41

Mural thrombosis is also an associated

4:45

finding of aneurysmal growth and may indicate that the patient might need an

4:49

intervention sooner rather than later.

4:51

Of all the peripheral arteries, other than visceral arteries, obviously,

4:56

the most common peripheral artery that can have an aneurysm is a popliteal

5:00

artery.

5:01

Obviously, because our coverage is all the way from the dome of the diaphragm to

5:04

the feet, visceral artery aneurysms can also be found on our image data

5:08

set.

5:09

The reason why

5:11

we intervene when they're large is because they can lead

5:15

to acute limb ischemia, form a nidus for

5:19

embolic formation because they can develop thrombus

5:22

within. There can be distal progression of the clot as well as rupture of

5:26

aneurysms.