0:01

Hey everyone, it's Mark and, uh, welcome.

0:04

This is the last session on, uh, ground glass.

0:06

We're going to look at the chronic ground glass,

0:09

um, diseases that have a fair bit of fibrosis.

0:13

So we're going to look at just, and there's not,

0:16

there's a, there's not a big differential here.

0:18

This is a short differential.

0:20

The most important thing is if you see

0:22

chronic ground glass in the setting of

0:25

moderate to severe imaging evidence of

0:27

fibrosis, these will be your players.

0:31

How do you approach them?

0:32

Well, distribution, presence

0:34

or absence of honeycombing.

0:35

And I'm going to give a shout out for

0:37

the DLCO, which is a PFT measurement

0:40

of diffusion, uh, to look at the

0:42

lung parenchyma and, um, functioning.

0:46

Uh, I'm also going to give you

0:49

some information on what you should

0:50

be looking for on every patient.

0:53

with pulmonary fibrosis, especially UIP.

0:56

You have to look for this.

0:58

All right.

0:59

So chronic ground glass, again, we're

1:02

going to look into fibrosis, but we're

1:03

going to look at these and notice how

1:04

the differential is a lot smaller.

1:07

It's UIP, so-called usual interstitial

1:09

pneumonitis, chronic hypersensitive

1:10

pneumonitis, and fibrotic NSIP.

1:12

And fibrotic NSIP and chronic hypersensitive

1:14

pneumonitis have a lot of overlap.

1:18

So review again: What are the five major imaging

1:22

findings associated with pulmonary fibrosis?

1:24

It's chronic ground glass with imaging

1:26

evidence of fibrosis in it, reticulation,

1:28

the nets, the, um, the web kind of appearance

1:32

of lines, traction bronchiectasis,

1:35

honeycombing, the most difficult, and the

1:38

irregular visceral pleura, where you have

1:41

that serrated appearance to the pleura.

1:43

So, a 67-year-old, they got chronic ground glass,

1:46

but oh my God, they have reticulation, irregular

1:49

visceral pleura, traction bronchiectasis.

1:53

This is a very advanced

1:54

amount of pulmonary fibrosis.

1:56

Is this, uh, going to be DIP?

1:59

No, no, not really.

2:01

This is going to be most likely UIP.

2:04

We look to see if there's honeycombing.

2:05

If there is, which this is very

2:07

difficult to tell, but I think

2:09

there might be right around there.

2:11

There may be; if you see honeycombing,

2:13

you come down hard and call it UIP.

2:15

But in this case, it's UIP.

2:18

What is it?

2:19

Uh, usual interstitial pneumonitis

2:21

is an advanced form and an end-stage

2:23

form of pulmonary fibrosis.32 00:01:12,804 --> 00:01:14,725 And fibrotic NSIP and chronic hypersensitive

1:14

pneumonitis have a lot of overlap.

1:18

So review again: What are the five major imaging

1:22

findings associated with pulmonary fibrosis?

1:24

It's chronic ground glass with imaging

1:26

evidence of fibrosis in it, reticulation,

1:28

the nets, the, um, the web kind of appearance

1:32

of lines, traction bronchiectasis,

1:35

honeycombing, the most difficult, and the

1:38

irregular visceral pleura, where you have

1:41

that serrated appearance to the pleura.

1:43

So, a 67-year-old, they got chronic ground glass,

1:46

but oh my God, they have reticulation, irregular

1:49

visceral pleura, traction bronchiectasis.

1:53

This is a very advanced

1:54

amount of pulmonary fibrosis.

1:56

Is this, uh, going to be DIP?

1:59

No, no, not really.

2:01

This is going to be most likely UIP.

2:04

We look to see if there's honeycombing.

2:05

If there is, which this is very

2:07

difficult to tell, but I think

2:09

there might be right around there.

2:11

There may be; if you see honeycombing,

2:13

you come down hard and call it UIP.

2:15

But in this case, it's UIP.

2:18

What is it?

2:19

Uh, usual interstitial pneumonitis

2:21

is an advanced form and an end-stage

2:23

form of pulmonary fibrosis.

2:26

And a lot of people use the term

2:27

idiopathic pulmonary fibrosis or IPF.

2:31

I don't use it because we talk in

2:32

pathology when we, when we do radiology,

2:35

but IPF is a term used when you have UIP.

2:39

but no etiology.

2:41

Strikingly, this is peripheral and basilar.

2:44

It's very peripheral, right up

2:45

against the pleura and basilar.

2:47

Okay.

2:48

There's going to be imaging

2:50

evidence of fibrosis.

2:51

And the most important one

2:52

to look for is honeycombing.

2:53

If it's there, it's going to be UIP.

2:56

These folks tend to be very hypoxic and

2:58

have a very low DLCO, much more than NSIP.

3:03

These people, histologically, their basement

3:05

membrane is exposed, and when you expose

3:08

it, the lung does not do well with that.

3:12

Um, there are FDA-approved medical

3:15

therapies that are used just for UIP

3:17

as opposed to all of the other ones.

3:19

And this has become a hot topic

3:21

in trying to diagnose these days.

3:23

And every one of these patients, you

3:26

have to look for evidence of pulmonary

3:28

hypertension, any new nodules,

3:31

and ground glass opacities that are new and

3:33

don't have a lot of fibrosis within them.62 00:02:26,174 --> 00:02:27,905 And a lot of people use the term

2:27

idiopathic pulmonary fibrosis or IPF.

2:31

I don't use it because we talk in

2:32

pathology when we, when we do radiology,

2:35

but IPF is a term used when you have UIP.

2:39

but no etiology.

2:41

Strikingly, this is peripheral and basilar.

2:44

It's very peripheral, right up

2:45

against the pleura and basilar.

2:47

Okay.

2:48

There's going to be imaging

2:50

evidence of fibrosis.

2:51

And the most important one

2:52

to look for is honeycombing.

2:53

If it's there, it's going to be UIP.

2:56

These folks tend to be very hypoxic and

2:58

have a very low DLCO, much more than NSIP.

3:03

These people, histologically, their basement

3:05

membrane is exposed, and when you expose

3:08

it, the lung does not do well with that.

3:12

Um, there are FDA-approved medical

3:15

therapies that are used just for UIP

3:17

as opposed to all of the other ones.

3:19

And this has become a hot topic

3:21

in trying to diagnose these days.

3:23

And every one of these patients, you

3:26

have to look for evidence of pulmonary

3:28

hypertension, any new nodules,

3:31

and ground glass opacities that are new and

3:33

don't have a lot of fibrosis within them.

3:36

These three are associated complications.

3:39

So, first of all, this patient's got UIP.

3:42

There's the honeycombing,

3:44

reticulation, peripheral.

3:45

There's a speculated nodule

3:46

in the right upper lobe.

3:47

What is it?

3:48

It's lung cancer.

3:49

What's your differential?

3:50

It's lung cancer.

3:51

Could be a zebra.

3:52

It's lung cancer.

3:53

Should we biopsy?

3:54

It's lung cancer.

3:56

Lung cancer occurs a striking amount of

4:00

time in patients with UIP, much more than

4:02

emphysema. In a study done at Michigan,

4:05

it was four times greater to have lung cancer

4:07

if you had pulmonary fibrosis of

4:08

UIP than widespread emphysema.

4:11

Okay.

4:12

Any new nodule

4:13

is lung cancer until proven otherwise.

4:18

Active search for the pulmonary arteries.

4:20

This slide's been low.

4:21

The clinicians and radiologists all

4:23

the time address the pulmonary artery.

4:26

Is it bigger than the ascending aorta diameter?

4:30

And pretty much any pulmonary

4:31

artery that's greater than 3.5

4:33

centimeters probably is

4:35

pulmonary hypertension.

4:36

This is important because this causes the

4:39

patients to keep coming in for follow-up

4:41

visits, with edema in the lower extremities.

4:44

They need a change in the therapy

4:47

to address this pulmonary artery

4:48

hypertension, which is a very common

4:51

association/complication with UIP.

4:55

The third thing to look for

4:57

is evidence of ground glass.

4:58

Now, this ground glass has a

5:00

lot of fibrosis around it.

5:01

We expect that this doesn't have quite as

5:04

much, and it's new. This patient has been

5:08

experiencing increasing dyspnea and deterioration

5:12

basically over the prior two months.

5:15

When you see new ground glass opacities

5:17

without a lot of fibrosis, that signifies

5:19

an acute deterioration in a patient

5:21

with UIP, and its pathology has been

5:24

shown to be diffuse alveolar damage.

5:26

This is not a good situation.

5:28

These people usually end

5:31

up dying relatively soon after.

5:34

They can try to address the diffuse

5:35

alveolar damage, but the therapies

5:37

sometimes don't work so well. But

5:39

at least you have to warn the patient.

5:41

Okay.

5:42

So, the other thing, reliance on

5:44

imaging has increased substantially.

5:46

All right.

5:47

Pathology is not considered the gold

5:49

standard in diffuse lung disease.

5:50

It is not.

5:52

Radiology has a central role.

5:55

So, it's time to earn that paycheck.

5:57

You can't really say, well, it's pulmonary

5:58

fibrosis, whatever, non-specific.

6:01

No, you have to kind of

6:03

address it a little bit more.

6:04

Is this peripheral?

6:05

Does it look like UIP?

6:06

Are the findings

6:08

not consistent with UIP?

6:09

It's more hypersensitivity.

6:11

We need to earn our paycheck.

6:13

When you're approaching someone with

6:15

fibrosis and an extensive amount of

6:17

fibrosis, plus or minus ground glass,

6:19

remember, pathology is not the gold standard.

6:21

Take a look at it.

6:22

What's the distribution?

6:24

And then these are sort of the reporting

6:26

that the Fleschner Society white

6:28

paper from 2017 recommended it.

6:31

Radiologists try to use.

6:32

Is the pattern typical for UIP?

6:34

If it is, no biopsy occurs.

6:36

They go to get treatment for

6:38

their pulmonary fibrosis UIP.

6:40

The key here is that there's honeycombing and

6:43

there are absent features that are inconsistent.

6:47

Probable UIP.

6:48

Well, it's peripheral, it's reticulation,

6:51

irregular visceral pleura, but there's,

6:53

you can't tell if there's no honeycombing.

6:56

Well, still probably UIP.

6:59

But there's no honeycombing.

7:00

And when you say probable, there's

7:02

still a pretty high percentage

7:03

it's going to be UIP, and many people

7:06

also skip biopsy and go to treatment. Then

7:09

you look into see if findings are indeterminate

7:12

or consistent with another pathologic process.

7:15

What are some things that are inconsistent?

7:17

Well, upper lobe disease processes

7:20

that's not bronchovascular distribution.

7:22

That's not perilymphatic

7:25

nodules or a lot of nodules.

7:26

That would tell

7:28

us it's probably something else.

7:30

Central lobular nodules, predominance

7:33

of ground glass without a lot of imaging

7:36

evidence of fibrosis, probably not UIP

7:39

and, of course, cysts or consolidation.

7:41

So these features, when seen, would

7:44

suggest it's something else.

7:46

So chronic ground glass with

7:49

associated moderate fibrosis.

7:50

What's its distribution?

7:51

Well, it's bronchovascular.

7:53

Also, I want you to note, look

7:55

at the pleural subpleural area.

7:56

It's spared.

7:58

There's no honeycombing here.

7:59

It's just sparing of the subpleura.

8:01

This is a key feature.

8:02

It's subtle, but it's key.

8:05

That tells us, okay, you know what?

8:06

This person's got NSIP, fibrotic NSIP.

8:11

That's what it is.

8:11

And this person had an autoimmune

8:13

disease, which went along with it.

8:16

Now, NSIP, the fibrotic spectrum, again,

8:18

I'm reminding you, this is not a disease.

8:21

It's a pathology, and there are

8:23

many different diseases that can

8:25

funnel into NSIP if left unchecked.

8:28

The fibrotic form will have evidence, obviously,

8:31

of fibrosis, and it'll be a predominance of

8:34

reticulation and some chronic ground glass.

8:38

You will always want to get expiratory

8:41

images on any of these diffuse lung

8:43

diseases because areas of air trapping in

8:46

something that looks like NSIP will probably

8:49

be chronic hypersensitivity pneumonitis.

8:52

Okay.

8:53

Honeycombing is a lot less common.

8:56

It's only about 7 percent honeycombing on

8:59

one pathology study with fibrotic NSIP,

9:01

as opposed to UIP, which is very common.

9:04

And hypoxia is not as severe,

9:07

and that's a huge clue.

9:08

You can use that in your reports.

9:10

Right.

9:11

The basement membrane is not exposed or not

9:14

as often exposed as it is in UIP, and their

9:18

level of hypoxia is a lot less profound.

9:21

Prognosis is obviously a lot better than UIP.

9:24

My feeling is that cellular NSIP,

9:26

if left unchecked, becomes fibrotic NSIP,

9:28

and if left unchecked, becomes UIP.

9:34

Okay.

9:34

Dyspnea on exertion, five

9:36

months, chronic ground glass.

9:37

This patient, when you look, has a

9:39

heavy smoking history, has areas of

9:41

emphysema, not a lot of fibrosis, basilar,

9:45

peripheral, very characteristic for

9:47

disquieting interstitial pneumonitis.

9:50

No treatment was sought.

9:52

He didn't quit smoking.

9:53

What happened eight years later, the

9:55

fibrosis and the injury just kept occurring.

9:58

And now he's got a fibrotic NSIP

10:00

pathology, secondary to progression to DIP.

10:04

Again, fibrotic NSIP is not a diagnosis.

10:07

It's a pathology.

10:09

In this case, it's secondary

10:10

to DIP that was left unchecked.

10:13

Okay.

10:13

NSIP.

10:16

Subpleural sparing is a big feature.

10:18

Many causes are many fibrotic NSIP, as

10:22

opposed to UIP, which you've

10:24

got to have that pleura involved.

10:26

So bronchovascular distribution,

10:29

subpleural sparing, traction

10:31

bronchiectasis, irregular visceral pleura.

10:33

These are all features that are

10:34

characteristic for fibrotic NSIP pathology.

10:37

You try and then you'd say, well, you know,

10:39

maybe it's drug, maybe it's autoimmune.

10:41

In this case, it was autoimmune.

10:44

Now this patient inspiratory and expiratory.

10:46

I'm going to say it again.

10:48

When you protocol these CTs with diffuse

10:50

lung disease or chronic symptoms, inspiratory

10:52

and expiratory, get the expiratory.

10:55

In this person, I put arrows, but

10:56

there are areas of air trapping.

10:59

So there's the chronic ground glass,

11:00

there's the irregular visceral

11:01

pleura, there's some fibrosis.

11:03

But these areas of air trapping tell

11:05

us that this is secondary to chronic

11:07

extrinsic allergic alveolitis, right?

11:10

The inhaled version of hypersensitivity pneumonitis.

11:13

It causes air trapping to occur because

11:15

the inflammation and fibrosis and

11:17

scarring occur in the small airways.

11:22

63-year-old male.

11:23

This is a typical, this is going to be typical.

11:25

You're going to see this all the time.

11:27

Okay, progressive dyspnea over a year or so.

11:31

You look and you say, well, yeah,

11:32

there's reticulation, irregular

11:33

visceral pleura, little ground glass.

11:36

Hmm.

11:37

Okay.

11:38

No honeycombing.

11:39

Is this, um, do you think it's fibrotic UIP?

11:44

Could a DLCO help here?

11:46

Yes, it could.

11:47

If the DLCO is higher by 80%, you'd say,

11:50

Hey, we favor that this is going to be

11:53

more of a fibrotic NSIP pathology, but in

11:57

this case, this patient did have a DLCO

11:59

of 66%, yet look, it's not that severe.

12:04

Okay, that tells us it's probably UIP.

12:08

It's probably UIP.

12:10

So what would your impression be for this CT?

12:13

Okay, indeterminate pulmonary

12:14

fibrosis, consult pulmonology.

12:16

Fibrosis likely represents drug toxicity

12:19

or connective tissue pathology.

12:21

Okay, you know that's wrong already because

12:23

drug toxicity and connective tissues, these

12:24

are not pathologies, they are etiologies.

12:27

Imaging typical for UIP, findings probable

12:30

for UIP fibrosis versus possibly NSIP.

12:34

Well, when you look at it, it's, it's

12:36

characteristic, honeycombing, traction

12:38

bronchiectasis, peripheral basilar.

12:40

This is your report, which should say

12:43

this is typical for UIP, patient doesn't

12:46

get a biopsy and goes on for treatment.

12:50

Last one, just as a reminder, the chronic ground

12:54

glass and all of these diseases get a little

12:56

confusing when we mix up pathology and etiology.

12:59

Remember, we look at the morphology and

13:02

distribution from the images to come to a report

13:04

conclusion on what we think is the pathology,

13:07

and then we can offer possible etiologies.

13:09

This patient, now you look at it, you're

13:12

saying, yep, no honeycombing, little

13:14

subpleural sparing, traction bronchiectasis,

13:17

moderately advanced pulmonary fibrosis, most

13:19

consistent with fibrotic NSIP pathology.

13:22

UIP is much less likely or unlikely.

13:26

Consider non-immune disease or drug

13:27

toxicity as possible etiologies.

13:30

And you see how you separate them.

13:31

If tissue sampling is considered,

13:33

suggest a VATS procedure.

13:35

There's your report.

13:37

With that, that's the end

13:38

of chronic ground glass.

13:40

Just summarizing, moderate to severe fibrosis,

13:42

small differential but important diseases

13:45

presence of honeycombing strongly suggests

13:48

UIP. So be careful and be careful about how

13:51

to report it. Active search for nodules, new

13:54

ground glass, and pulmonary hypertension in all

13:56

patients with pulmonary fibrosis, especially

13:58

UIP. And durations of symptoms and things like

14:02

DLCO can be very helpful in organizing which

14:06

you put. And also remember you’ve got to earn

14:08

your paycheck now, people. Pathology is not the

14:11

gold standard for diffuse lung disease. Radiology

14:14

and imaging have a central role with that.

14:17

I hope you found it helpful.

14:18

And, uh, thank you very much.