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Okay.

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Hi, everyone.

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It's Mark again, and we're moving on,

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and we're going to talk about a topic

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here that, uh, I hope you find helpful.

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It's really common.

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So, um, hopefully it will be useful.

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We're going to talk about the imaging

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approach to fibrosis, fibrosis,

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part of the diffuse lung disease.

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Kind of spectrum.

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Um, the main objective is to go over the five

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main morphologic imaging patterns of fibrosis

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and talk about the importance of honeycombing

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in particular, because that one kind of

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signifies a particular disease and understand

0:34

when we start going into this chronic ground

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glass, that the presence and extent of fibrosis

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significantly changes your differential.

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There are certain things that you wouldn't see

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in a chronic ground glass with a lot of fibrosis

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or say, as opposed to if there were no fibrosis.

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So this is kind of a key

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when you approach a

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chronic ground glass process.

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So first of all, let's define it.

1:00

What fibrosis, how's that

1:02

different from scarring?

1:03

Well, fibrosis refers to the

1:04

connective tissue deposition.

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And, you know, it's part of this normal healing.

1:09

It's usually seen as an

1:11

organizing pathologic process.

1:14

An example would be usual interstitial

1:16

pneumonitis, um, NSIP, um, as opposed to

1:20

scarring, which that's fibrosis too, but

1:23

that's fibrosis secondary to an injury,

1:26

say, um, residual from a prior necrotizing

1:29

pneumonia or infarct will leave a scar.

1:32

It's fibrosis, but it's

1:33

secondary to a prior injury.

1:36

So the imaging evidence or imaging of

1:38

fibrosis is five main morphologic appearances:

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chronic ground glass opacity, irregular

1:44

visceral pleura, reticular opacity, traction

1:47

bronchiectasis, and then honeycombing.

1:49

Okay, the honeycombing, by the

1:51

way, is one of the most difficult.

1:55

It really is tricky.

1:57

And it's important.

1:58

So the whole basis of fibrosis is when it occurs

2:02

pathologically and histologically, there is a

2:05

retraction, a volume loss, which then causes

2:08

a distortion of that parenchymal anatomy.

2:12

So, it can manifest as a kind of

2:15

chronic ground glass process,

2:16

but the ground glass really should

2:18

have other evidence of fibrosis in it.

2:22

Reticular, which just means it's

2:24

a net-like kind of thing, uh, lines

2:27

that crisscross, okay, reticulation.

2:30

Traction bronchiectasis is the pulling apart

2:33

of the airways because of that surrounding

2:36

parenchyma volume loss and retraction,

2:38

it pulls it apart and makes it wider

2:40

and it's called traction bronchiectasis.

2:42

Nothing wrong with the airway; it's just the

2:45

airway lives in a really bad neighborhood, okay?

2:47

So it's secondary to that.

2:49

Irregular visceral pleura,

2:51

which I find very helpful.

2:52

The pleura should be nice and smooth.

2:55

Nice and smooth.

2:57

When it starts looking spiculated,

2:59

that's again a sign of retraction.

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And last is the honeycombing, one of the most

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important and very difficult, these small

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cysts that are smack up against the pleura.

3:09

So let's look at each of them.

3:11

Chronic ground glass.

3:13

The more imaging evidence of fibrosis

3:15

within that ground glass tells us that the

3:19

ground glass actually reflects fibrosis.

3:23

So this person's got a lot of ground glass,

3:25

but no imaging evidence of fibrosis, right?

3:27

Visceral pleura is good.

3:28

No traction.

3:29

This is, this isn't fibrosis, right?

3:32

This represents alveolar prognosis.

3:34

In this case, this patient's got some

3:36

ground glass chronic, a little bit of

3:38

irregular visceral pleura traction.

3:40

So it represents some fibrosis here, and

3:45

then you get into this, which is like

3:46

there's traction bronchiectasis, irregular

3:48

visceral pleura, see that serrated night,

3:50

uh, serrated appearance, um, very diffuse.

3:54

That's pretty much if you biopsy it, it's going

3:56

to be fibrosis, in this case, fibrotic NSIP.

4:00

This patient has got ground glass and not

4:04

a lot of imaging evidence for fibrosis.

4:07

It was treated with corticosteroids and a lot of

4:10

it got improved, but some of it didn't go away.

4:14

And the areas that didn't go away

4:16

are these areas of ground glass with

4:18

evidence of fibrosis within it, traction

4:20

bronchiectasis, irregular visceral pleura.

4:22

So, the more evidence of fibrosis

4:26

within the ground glass, the less likely

4:29

it will improve with therapy.

4:31

Okay.

4:34

The irregular visceral pleura, one of my

4:35

favorites, the pleura should be nice and sharp.

4:38

Look at this serrated appearance, right?

4:41

Another one here, a little bit of a

4:42

serrated appearance here, scarring.

4:45

And you can tell when you see this kind

4:48

of serrated or irregular visceral pleura

4:51

that the underlying parenchyma has evidence

4:54

of fibrosis or scarring, but fibrosis,

4:57

and it retracts and pulls the pleura and

5:01

it tugs it in and gives it that kind of

5:04

little speculated shape at various points.

5:07

Okay.

5:07

And that's the distortion.

5:10

Reticulation is actually just lines, right?

5:13

And they're intersecting and it's like

5:16

a net or a web of intersecting lines.

5:19

We don't tend to see those so-called

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curvilinear interlobular septation thickening

5:24

normally because of the parenchyma gets

5:27

so distorted, they get distorted too.

5:30

So you see these crisscrossing lines often in

5:33

the setting with the irregular visceral pleura

5:35

and maybe associated traction bronchiectasis.

5:38

Okay.

5:39

So this is reticulation, another

5:40

sign, morphologic sign of fibrosis

5:46

and, uh, traction bronchiectasis.

5:48

Well, this can be seen with any

5:50

real cause of scarring or fibrosis.

5:53

Um, this patient has cryptogenic organized

5:55

pneumonia, chronic consolidation, and you can

5:58

see how the airways are being pulled apart.

6:01

Same here.

6:02

Being pulled apart by the reticular capacities,

6:05

being pulled apart, traction bronchiectasis,

6:07

a very good sign of underlying fibrosis.

6:10

Again, it's not the airway

6:12

problem that is the issue.

6:14

It's the fact that the airways get pulled apart.

6:17

Okay.

6:18

Now, um, traction bronchiectasis is almost

6:21

always varicose in appearance because it has

6:23

different attachments that get pulled apart.

6:28

Okay.

6:29

Lastly, honeycombing, one of the most difficult.

6:31

It's the, it's three to 10 millimeter sort

6:34

of spheres, cystic spaces that are thick and

6:37

walled, and they usually are next to one another.

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Now, the key thing here is that it

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has to be right up against the pleura.

6:44

It has to be right up against the pleura.

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I cannot emphasize that.

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And it can be single file or it

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can be heaped up on one another.

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As honeycombing progresses, it starts in that

6:59

subpleural area right up against the pleural area.

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And when it progresses, it progresses centrally.

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So it goes peripheral to central, so it

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is conceivable that you will find areas

7:09

of honeycombing that will be single

7:10

layer because some people teach that

7:11

it has to be on top of one another.

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It's a lot easier if it's on top of one

7:15

another, but it does not have to be.

7:18

It represents the advanced end-stage lung

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disease, fibrosis, and is strongly associated

7:24

with usual interstitial pneumonitis.

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Which many people call

7:29

idiopathic pulmonary fibrosis.

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It, in fact, is one of the most

7:34

specific findings for UIP, IPF.

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And that's why it's really important

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because if you mention it in your report,

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that people are going to assume it's

7:44

probably UIP and get treatment for it.

7:46

For that, even potentially without a biopsy.

7:49

So you want to be careful when looking at it.

7:52

So again, look, are they

7:54

right up against the pleura?

7:55

Yes.

7:55

They're heaped up.

7:56

Yes.

7:56

There's traction bronchiectasis,

7:57

irregular visceral pleura.

7:59

It's peripheral.

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Yeah.

7:59

That's UIP and honeycombing.

8:02

This one gets a little bit more difficult.

8:04

Is this honeycombing?

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Hmm.

8:06

Yeah, I think it is.

8:08

How sure am I?

8:09

Yeah.

8:12

I'm moderately sure, but you see, it's tough.

8:15

And if I'm, and if I'm not sure, I'm, I'm

8:17

probably not going to come down totally on UIP.

8:20

Although that one is, you can

8:22

just tell by the distribution.

8:25

Okay.

8:26

Uh, what does it look like,

8:27

uh, on the plain film?

8:28

Well, reticulation and honeycombing looks

8:32

like little, uh, crisscrossing webs of

8:35

lines forming these little ant-sized holes.

8:38

Okay.

8:39

And that's

8:40

what you see here again, honeycombing,

8:43

this is cysts that are forming these

8:45

reticulations right up against the

8:47

pleura peripherally. That's honeycombing.

8:50

That's UIP.

8:51

Okay.

8:52

And again, once you say it, people

8:54

are going to assume it's UIP.

8:56

So this patient has fibrosis as well, right?

9:00

This is cryptogenic organized pneumonia,

9:02

and you can see the consolidation, but you

9:04

have that sort of irregular visceral pleura,

9:07

you've got the traction bronchiectasis, and

9:10

that architectural distortion and

9:13

architectural distortion is a displacement

9:15

of the normal anatomy of the vessels

9:20

and bronchi.

9:21

They get distorted and pulled, right?

9:23

Is that retraction?

9:25

And you can see that retraction occurring here.

9:27

And that tells you it's chronic and that there

9:29

is evidence of fibrosis or scarring present.

9:33

Another patient here with sarcoidosis,

9:35

it's got that bronchovascular

9:37

pattern. There are lots of nodules, but take a look.

9:38

You can see this retraction and architectural

9:41

distortion here, even on a plain film. That

9:44

tells you that there is stage four sarcoidosis

9:46

and yes, there is evidence here of fibrosis.

9:51

One other very helpful sign of fibrosis or

9:54

scarring is when the hilum is pulled up,

9:57

kind of like old man's pants in Florida, right?

10:00

Pull up that belt, the hilum gets

10:02

pulled up and that only really kind

10:03

of occurs in the chronic setting.

10:06

And this patient has multiple pulmonary

10:08

nodules, significant retraction, scarring,

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and in this case, it was silicosis.

10:13

So, take a look.

10:17

Is there imaging evidence of fibrosis?

10:19

Yes.

10:20

Irregular visceral pleura, for sure.

10:22

Reticulations, a little bit of

10:23

ground glass with some fibrosis.

10:25

Is there also honeycombing?

10:28

You take a look.

10:29

These look like they're

10:30

right up against the wall.

10:31

Yeah, I think there's honeycombing.

10:34

What does this patient have?

10:35

They have usual interstitial pneumonitis or UIP.

10:38

Does this patient have honeycombing?

10:40

Because they have reticulation, ground glass,

10:43

and you see these little kind of cystic areas.

10:45

But take a close look at them.

10:47

They are not up against the pleura.

10:50

They are not up against the pleura.

10:51

This is not honeycombing.

10:53

This is not honeycombing, but it

10:55

can be easily confused with it.

10:58

So these were actually little cysts

11:00

or emphysema that were formed.

11:03

This is honeycombing right

11:05

up against the pleura.

11:05

Remember, it's got to be against the pleura.

11:08

So, summary: the five main morphologic

11:12

appearances of fibrosis are ground glass opacity,

11:15

especially with evidence of fibrosis within

11:18

it, reticulation, traction bronchiectasis

11:22

pulled apart, honeycombing right up against the

11:25

pleura, and the irregular visceral pleura sign,

11:28

that little serrated appearance to the pleura.

11:30

I hope you found that helpful as we move

11:34

through the chronic ground glass differential.

11:37

Thanks.