0:00

Our next case is that of a mycotic

0:04

pseudoaneurysm. This is a patient who came in with

0:08

aortic valve vegetations and is

0:11

undergoing a CT angiogram. Now,

0:15

right at the top of the pad, knowing that they have valve vegetations, seeing

0:19

that they have renal infarcts suggests that we might find either an embolic

0:23

phenomena or a mycotic pseudoaneurysm.

0:26

So our threshold of

0:29

finding something is high on this scan already.

0:32

As I'm scrolling down, we can see that up until now, all the arteries are

0:36

patent.

0:38

Both the superficial femoral arteries are patent.

0:41

There's obviously all this artifact from the

0:44

right knee prosthesis, and it does affect the

0:48

assessment of the contralateral side as well a little bit, as well as the

0:51

ipsilateral side. A short segment is difficult to assess.

0:55

But even so, under that, you can see that there's this

0:59

irregular enhancing structure arising from

1:03

that popliteal artery,

1:06

and the proximal

1:09

branches of that tibial peroneal trunk

1:13

is involved as well. There's a large amount of associated

1:17

thrombus that we can see along it.

1:20

Before calling something a thrombus, though, it's important to also look at the

1:23

delayed phase, which is what we're going to look at next.

1:27

So looking at that delayed phase imaging right here and going directly to the

1:30

area of interest, you can see that there's a large amount of thrombus here along

1:34

that pseudoaneurysm. But more notably, if you look at that

1:38

sac, there is enhancement and peripheral enhancement, and that's

1:41

pathognomonic of a mycotic

1:44

pseudoaneurysm. Having enhancing walls,

1:48

as I pull it up here again.

1:51

So having all these enhancing walls

1:56

along the pseudoaneurysm sac

2:00

is suggestive of a mycotic pseudoaneurysm.

2:06

Then the mycotic pseudoaneurysm has associated thrombus, and so there's a short

2:10

segment stenosis of that tibial peroneal trunk as it's

2:13

involved by the pseudoaneurysm and thrombus as well.

2:17

But then distally, it's reconstituted and

2:21

all the three calf arteries are patent.

2:24

Another important thing to see here is the

2:28

difference between having a metal artifact reduction algorithm

2:32

versus not having one.

2:34

And so

2:36

I have two reconstructions here.

2:41

So this is an arterial phase with the metal artifact reduction

2:44

algorithm, and a

2:49

delayed phase image without the metal artifact reduction algorithm.

2:52

And if I put both of them side by side, I think you can see that this has

2:56

much lesser artifacts, and you can see

3:00

more of the popliteal artery segment

3:04

compared to without the MARS

3:08

or the metal artifact reduction software.

3:11

Right. Other than that, this patient, obviously in the setting of

3:15

the mycotic pseudoaneurysm, has hyperemia in this vessel, so there's early

3:18

enhancement of these superficial veins.