0:00

Moving on to the next case. And uh, this is an interesting one.

0:04

I still remember I was reading the chest x-ray on this patient.

0:07

So imagine I can't remember what the precise history was,

0:11

but I would imagine if I had to just take a guess,

0:14

it would've been something like shortness of breath.

0:16

So when you're looking at this x-ray, uh, you can see that the heart is big.

0:20

In fact, the right atrium was big. You can see the right ventricle.

0:24

It has significant amount of contact with the sternum indicating right ventricle

0:28

enlargement.

0:29

The apex is however the LV type of apex and in fact you can see that the left

0:33

ventricle is enlarged as well. So there's clearly gotten cardiomegaly going on.

0:38

Something that caught my attention at the time I was reading the X-ray was right

0:43

here. You kind of saw an opacity, uh, related or in this particular region.

0:49

So as we normally do,

0:50

you want to look for any prior imaging you can find or you look for any

0:53

cross-section imaging you could compare it to.

0:56

So luckily this patient had a CT abdomen and uh,

1:00

I want you to look at the CT abdomen.

1:02

So I just pulled it out for comparison when I was reading the chest x-ray.

1:06

Unfortunately it didn't go too high so we couldn't really correspond it or I

1:11

couldn't really, uh,

1:12

correlate it exactly with the abnormality I was seen on the x-ray.

1:16

But looking at the size of this particular vein,

1:19

I started feeling that maybe this was just a venous structure.

1:23

Having said that,

1:24

I would like you to just look at the CT as a whole and see if you can pick up

1:29

anything else on the ct, anything that is,

1:32

that may be interesting or would uh,

1:37

suggest doing something different for the patient.

1:41

So once we've run it a few times,

1:44

let me show you the question for this question.

1:47

So what is the next best step in this particular exam?

1:50

Let's say you looked at that x-ray. Uh,

1:52

would you like to do a non gated contrast enhanced ct?

1:57

Would you like to do a gated contrast enhanced ct?

2:00

Would you like to do a non-contrast CT chest or would you think no further

2:04

investigation?

2:04

Since in all likelihood what we were seeing on the x-ray seemed to be just a

2:09

vascular structure. So

2:13

let's wait for everybody to think about that question again.

2:17

So remember the x-ray,

2:18

we saw a questionable finding and then when we were trying to correlate it,

2:24

we couldn't really correlate it very well on the CT because it didn't cover the

2:28

abnormality well enough.

2:30

But I want you to think about anything additional you may have seen on the CT of

2:34

the abdomen that would guide your next step.

2:40

All right, that is excellent.

2:43

So everybody thought about the con gated contrast enhanced ct and that is indeed

2:47

the correct answer in this case. So, um,

2:50

I'm pretty proud of the fact that everybody picked up that finding I was looking

2:53

at and let's revisit it one more time. So when I was uh,

2:57

comparing it to the chest x-ray, I definitely saw this and I thought, okay,

3:01

this doesn't seem to bothersome to me.

3:03

But what was catching my attention was the left AV groove. So here,

3:07

this is what was bothering me and when I was, let's run the movie again.

3:12

You can see there is too much happening in the left AV groove and I was quite

3:16

concerned that the patient's coronary arteries,

3:19

even on this non gated CT exam were dilated,

3:24

which made me worry about a particular diagnosis and I suggested a gated

3:29

contrast enhanced ct. So let me show you what happened. This patient came back,

3:33

got a gated contrast enhanced ct and now I'm going to run through this

3:39

movie.

3:39

We're going from the top to the bottom and what you're starting to see here

3:44

in the left AV groove is a very,

3:47

very dilated left circumflex artery and not only is it dilated,

3:50

it's markedly tortuous as well. So we are running it one more time.

3:55

You can see the right coronary artery is actually pretty normal in caliber.

4:00

Here is the left circumflex artery that is markedly tortuous. This is where it

4:07

comes in and let's run it one more time. Here is the left main,

4:11

this is the l a D here by the way,

4:13

this structure that has a much more normal caliber, the L A D is normal,

4:17

but the left means circumflex are markedly dilated. And uh,

4:22

you can see this is the coronary sinus that is also quite dilated and very

4:26

intimately related to the circumflex artery.

4:29

So once you've seen this finding here, let's look at the volume rendered images.

4:34

So we looking at the aortic root here,

4:37

this is the left anterior descending artery. It's uh,

4:40

running between the right ventricle and left ventricle.

4:43

Here is the right coronary artery and these seem pretty unremarkable,

4:46

but here is a very,

4:47

very dilated left main artery and this is the left circumflex coronary artery.

4:53

So let me spin this around so you can see it from another perspective as well.

4:56

Again, here is the R C A,

4:58

this is the coronary sinus and this is a very markedly dilated

5:03

circumflex artery.

5:08

So here it is, this is the coronary sinus. Very mark,

5:11

very dilated in tortuous left circumflex artery.

5:16

So the question is, what do you think is the most likely diagnosis?

5:20

Would you think it's atherosclerotic coronary artery aneurysm, Kawasaki disease,

5:25

bee's disease, or a coronary artery fistula?

5:30

So think about the dilatation of the coronary artery.

5:33

Think about the dilatation of the coronary sinus and what

5:38

entity would tie the two in together.

5:43

Okay, can we see the answers of the poll please?

5:47

And that's excellent.

5:48

Everybody thinks it's a coronary artery fistula and I totally agree with you.

5:52

So, Uh,

5:55

this is indeed a coronary artery fistula where the circumflex artery was

6:00

communicating anomaly with the coronary sinus leading to its dilatation.

6:04

And just to review, what is a coronary artery fistula,

6:07

it's basically a connection between a coronary artery branch and it can

6:11

communicate with a cardiac chamber or a venous or arterial structure like

6:16

coronary sinus S V c pulmonary artery or vein. In this particular image,

6:20

what you're seeing is, uh, this is the left anterior descending artery.

6:23

The arrow is pointing to a very dilated L E D proximally,

6:27

but soon after it gives off this very tortuous branch,

6:30

which was communicating with the pulmonary artery.

6:33

And after it gives off the branch, the caliber of the L E D significantly drops.

6:38

So this is a very,

6:39

very useful feature of coronary artery fistula and these tend to be congenital

6:44

in most cases.

6:46

So when you think about the left circumflex to coronary sinus fistula,

6:49

I want you to consider what are the problems with the fistula? Uh,

6:53

could I have the question please for the polling please? It's, uh,

6:57

does it lead to a left to right shunt in this case?

7:00

Would it lead to steel phenomenon or both?

7:09

All right, so let's see if we can get the results for the poll. Yeah,

7:14

that's excellent.

7:15

So it indeed does lead to both the left to right shunt because you have the

7:19

coronary artery ending in a right-sided structure.

7:22

It also leads to steel phenomenon because instead of the coronary artery

7:26

perfusing the myocardium, it now is running off into this coronary sinus.

7:30

So it's depriving the myocardium of its blood supply.

7:34

So that is indeed the correct answer. So like I said,

7:39

hemodynamics can be shunt and that could lead to ischemic symptoms. Uh,

7:43

these patients often have heart murmur and they could have a shunt depending on

7:48

where the fistula really drains into.