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All right. Now we're going to start our case series on peripheral arterial disease,

0:04

and the first one that we're going to start off with is arterial

0:08

inflow disease. This is a scan of a

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66-year-old male who's a

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smoker, has had an MI,

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CVAs, and complains of lifestyle-limiting claudication.

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As we're scrolling down, we're not going to look at all of the vessel anatomy,

0:26

but I will highlight pertinent findings when they're

0:30

important for diagnosis. Of course, when you're reporting them, you're going to

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basically look at all of the non-incidental findings in the vascular

0:37

tree

0:38

comprehensively. So as we're scrolling down, we can see that there is a

0:42

lot of atherosclerosis involving the aorta.

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At that level of that takeoff of the renal artery, so in that

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juxtarenal segment,

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there is

0:54

occlusion of the aorta and really no

0:57

opacification of this entire infrarenal aorta

1:02

all the way down.

1:04

These are both the common iliac arteries, which are diminutive in

1:08

caliber, and again, they do not show any contrast

1:11

opacification on either side.

1:14

When I read these studies, I like to focus one side at a time.

1:17

So typically when I'm interpreting them, I would look at one-sided

1:21

iliofemoral runoff system, and then I come back up, and then I look

1:25

at the other side.

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I also always have on my second screen the non-contrast

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image data set open, which helps me problem solve when there

1:35

are calcifications. And I'm able to link both

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of these series side by side, and you can help really kind of

1:43

see if something is contrast or if something is calcification.

1:47

All right. So as we're going back up again here, we see

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this occluded infrarenal aortic segment.

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We can see that this was the ostium of this

1:57

inferior mesenteric artery that came out.

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That's also occluded, but then it is reconstituted

2:03

again by a vessel over here.

2:07

And so this vessel forms a collateral

2:11

pathway that we're going to discuss again in a bit.

2:15

As we're going down, we noted again the small caliber of both

2:18

the common iliac arteries.

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And then there is reconstitution of the external iliac artery and

2:26

the internal iliac artery more distally.

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The internal iliac artery then shows contrast opacification, and while the

2:33

external iliac arteries are small and narrowed in caliber,

2:37

they are patent and reconstituted.

2:40

As we're going down, the common femoral arteries, the superficial, and the

2:44

profunda femoral arteries are patent.

2:47

Going back up to the left side, we see similar findings.

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So occlusion of that left common iliac artery, that

2:54

proximal left internal iliac artery, and the external iliac

2:58

artery.

2:59

And then there is opacification distally of the internal

3:03

iliac artery. And while this is narrow,

3:07

there's some degree of opacification of

3:10

that external iliac artery as well.

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And then coming more inferiorly, the common femoral

3:17

artery is patent. The superficial and deep femoral arteries are patent.

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And if you look at the remainder of the vessels in both the

3:25

lower extremities, the superficial arteries are patent bilaterally,

3:30

as are the popliteal arteries. And then as we're coming

3:33

down,

3:35

looking at the runoff vessels, the anterior tibial,

3:38

peroneal, posterior tibial arteries on both sides are widely

3:42

patent all the way down to the feet.

3:46

Going back up then and looking at that pattern of occlusion

3:50

and other things that we see. So we looked at the occlusion, we looked at

3:54

the reconstitution, but you would have noticed that this inferior epigastric

3:58

artery that's running in the rectus sheath are highly

4:01

engorged. They are tortuous. They are hypertrophied in

4:05

their caliber, as are these circumflex iliac branches on

4:08

both sides,

4:10

as well as this iliolumbar artery laterally over here,

4:15

all the way to the top. So if we were to look at this in a different imaging plane,

4:19

which would make it a little bit more obvious, and if I make this into a

4:23

maximum intensity projection. So here we

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saw that the rest of the aorta inferior to the

4:31

renal artery takeoff are occluded, as is

4:35

bilateral common iliac arteries, and there is distal reconstitution of

4:39

the external iliac arteries bilaterally.

4:42

But the reason why there is distal reconstitution and this

4:46

retrograde flow into the external iliac artery is because

4:50

there is an extensive collateral pathway that has developed in these

4:54

inferior epigastric arteries right here.

4:56

So both of these paired vessels right here, they form an

5:00

important collateral pathway as they anastomose

5:03

superiorly with the superior epigastric

5:07

artery, which are then continuations of the internal

5:11

thoracic or the internal mammary arteries on both

5:15

sides. There are also prominent subcostal and

5:18

intercostal arteries that you can see are these

5:21

torturous vessels all the way on both sides, as well as multiple

5:25

additional arterial collaterals anteriorly,

5:29

as well as in that circumflex arterial

5:33

territory.

5:35

Regarding that inferior mesenteric artery collateral that we saw, so this

5:39

was that marginal artery of Drummond, which also provides

5:42

a collateral pathway between branches of the superior

5:46

mesenteric artery and the inferior mesenteric artery and is able to distally

5:50

reconstitute.

5:53

And so these collateral pathways are really important.

5:56

They suggest chronicity, but also they provide

6:00

a nice framework of supply to the

6:04

rest and the distal lower extremity arteries.

6:08

There are many collateral pathways.

6:10

There are also named collateral pathways, so this pathway network of

6:14

an enlarged inferior epigastric artery that was anastomosing

6:19

more superiorly to the internal mammary arteries is also called as the

6:22

pathway of Winslow

6:25

and is really one of the most common ones that are implicated.

6:29

Clinical implication is that using one of these arteries in case a

6:33

person needs a coronary artery bypass graft would then be tricky

6:36

because essentially these are perfusing your lower extremity

6:40

arteries.

6:42

We also have the immediate delay scans that are done,

6:46

and you can see that there was no opacification

6:49

indeed of the infrarenal aorta and the common iliac artery.

6:53

So it's not that there's delayed perfusion or sluggish flow,

6:57

but rather that they are indeed

7:01

occluded.

7:03

This patient, because of the aortobifemoral occlusion,

7:07

underwent an aortobifemoral bypass graft, which means

7:10

that from the proximal aorta, they created a graft and

7:14

anastomosed it all the way to the femoral artery where it's already reconstituted,

7:18

and so it ensures maintained arterial

7:22

supply to both lower extremities.