0:00

What we can do when approaching lung cancer screening

0:03

cts is both use our eyes visually,

0:05

but we can also quantify some of the findings.

0:09

We can visually assess emphysema, how severe is it

0:12

and where is it distributed In the lungs.

0:15

We can look at small airway while thickening

0:17

and categorize it as mild, moderate, severe, depending on

0:20

how small the airway lumen has become relative

0:23

to the thickness of the wall.

0:25

We can look for mucus plugging

0:26

and even a few scattered small mucus plugs is now known

0:30

to be associated with increased patient morbidity

0:33

and poor outcomes and bronchiectasis With emphysema,

0:37

we can not only apply this visual rating of non mild,

0:41

moderate, severe, but there are many tools now

0:43

that will quantify emphysema

0:44

and make that easy to put in your radiology reports as well

0:47

as to follow the severity over time.

0:51

And then there's interstitial lung abnormalities

0:53

and fibrotic disease.

0:55

ILA or interstitial lung abnormalities are incidentally

0:59

detected and represent early evidence of pulmonary fibrosis.

1:03

When we see these, whether it's on a lung cancer screening,

1:06

CT or any chest ct, we should recommend referral

1:09

to pulmonary medicine with pulmonary function testing,

1:12

as well as testing for connective tissue disease,

1:15

which most pulmonary medicine physicians will undertake

1:18

because of the increased association with ILAs.

1:22

When patients are asymptomatic

1:24

and have normal functions with no evidence of CTD

1:28

patients should be followed up with pulmonary medicine

1:30

and usually do so annually with pulmonary function tests

1:34

or if they develop symptoms

1:36

because abnormality in pulmonary function tests developing

1:40

or new symptoms is indicative

1:42

of pulmonary fibrosis progression

1:44

for which antifibrotic therapies may then become indicated.

1:48

We know that 10 to 20% of patients with this mild evidence

1:52

of interstitial lung disease found on

1:55

chest cts incidentally, including our lung cancer screening,

1:58

cts, will progress over the next five to 10 years.

2:03

Here's an example of a 61-year-old baseline CT has mild

2:07

peripheral subpleural reticulation

2:09

and is asymptomatic at this time with normal pft,

2:13

but nine months later becomes symptomatic.

2:16

CT is repeated and we can see

2:17

that the disease extent has already progressed in the short

2:21

term at this time.

2:22

Through both of these time points.

2:24

Serologic tests remain negative with no evidence

2:27

of connective tissue disease.

2:29

This serial CT examination is the same patient

2:34

taken from the position paper from the Fleischer Society on

2:37

interstitial lung abnormalities,

2:38

which is a really good reference for this topic

2:41

and reviews the literature quite well.

2:43

This study is out of the COPD gene study,

2:46

which is a longitudinal study of COPD,

2:51

looking at ways to identify it earlier, understand it,

2:55

and to treat it so that we can prevent progression.

2:58

This patient in A-C-O-P-D study, which is A-C-O-P-D study,

3:02

not a fibrotic lung disease study, starts out

3:04

with a baseline CT with just some mild subtle reticulation

3:09

that might even go referred to as a little bit

3:11

of dependent ectasis

3:13

because there's not much else that was seen

3:15

four years later on their COPD gene research study.

3:19

We now see areas of dilated bronchi in the lung periphery

3:22

and more reticulation.

3:24

By 2010, we now see convincing evidence,

3:28

much more extensive amount of ground glass reticulation,

3:31

traction bronchiectasis,

3:33

and then through 2015,

3:35

12 years since the original detection,

3:38

we have considerable progression yet again

3:40

and starting to develop small honeycomb cysts.

3:43

So ILAs at their earliest when we identify them.

3:47

Patients with these findings should be referred

3:49

for pulmonary medicine function testing

3:51

and pulmonary consultation

3:53

to both understand the disease at current state

3:56

and decide whether antifibrotic therapies are important

4:00

today or should be used in the future if disease progresses

4:03

or symptoms are identified.

4:05

And lastly, I wanna talk briefly about quantitative analysis

4:09

of cts using tools

4:11

that can help us extract information from cts.

4:14

They can be applied both to interstitial lung disease,

4:17

looking for areas of increased lung density, ground glass,

4:21

and reticulation and subcategorize, those findings as well

4:24

as applied to emphysema to quantify the severity

4:28

of emphysema or to quantify small airway disease

4:31

by measuring the amount of air trapping.

4:33

This is an example of looking at interstitial lung disease

4:37

using one of these quantitative tools

4:39

where we can look at the normal lung shown in green,

4:43

whether it's superimposed on a coronal image,

4:45

whether it's using these sort of radar diagrams.

4:47

So you can see each lobe

4:49

and the extent of each different feature.

4:51

In this patient. We have ground glass demarcated.

4:54

In this yellow color, we have reticular in the orange color

4:59

and we had no honeycombing.

5:02

So we can measure how much disease is present versus

5:05

how much normal lung,

5:06

and we can measure the type of underlying abnormality.

5:10

Ground glass, generally more reversible.

5:13

Honeycombing and reticulation, generally irreversible.

5:16

If we're using antifibrotic medications, we can look

5:20

to see if they're having impact on the rate

5:22

of progression is slowing or the disease is held in check.

5:25

And we can break these findings down into details

5:29

to each lung, each lobe, and so on.

5:33

Most of these tools were originally developed

5:35

through radiologist ground truthing

5:37

of individual little vox.

5:39

And I participated in a number of these studies

5:41

where we took small pieces of the lung, as you can see here,

5:44

little voxel groupings of the lung

5:47

and decided whether they were ground glass, reticular,

5:50

honeycombing, normal lung,

5:51

and so on, so the tools could be developed to identify them.

5:55

And so most of the tools out there today have used some form

5:58

of radiologist ground truthing

6:00

as their underpinning in the way they quantify lung disease.