0:01

Let's see how you did when looking at this lung case from

0:04

a lung cancer screening examination

0:06

to identify the appropriate lung ran category.

0:09

We've got two exams here.

0:10

On the left is the 2021 screening exam

0:13

and on the right is the 2020 screening exam.

0:16

So one year between annual screens.

0:19

As we scroll through the lungs, we see a little bit

0:22

of mild apical scar, not an uncommon vining.

0:26

As we continue to scroll down the lungs,

0:29

we see a smoothly marginated lobulated nodule in the right

0:33

upper lobe apex.

0:35

It is a new solid nodule

0:39

and we can certainly measure it with our calibers

0:44

measures about 15 millimeters in its longest axis

0:48

and nine to 10 millimeters in its short axis.

0:52

So it's about 12 to 12 half millimeters in bean mean

0:55

diameter, which we use for lung rats

0:58

and the long rides categorization schema.

1:01

A new solid nodule over eight millimeters in mean diameter

1:05

is a category four B nodule.

1:08

So that's a very significant finding.

1:10

A patient should be recommended to a specialist such

1:12

as pulmonary medicine for further evaluation

1:15

and diagnostics to determine the significance

1:18

of this new nodule, which is developed in one year

1:21

and we continue to scroll down the lungs.

1:23

Are there any other nodules?

1:27

Oh, we come across another nodule.

1:29

This one's a little bit different.

1:31

It's acausal pleural based juxta pleural nodule.

1:34

It has a large surface of contact with the pleural surface,

1:38

an angular somewhat pointed or bi convex shape

1:43

and it hasn't changed.

1:44

In fact, if we look back at screening cts here that go back

1:47

through 2017, we can see that that nodule is present

1:52

and unchanged for many years time.

1:55

So this is a benign juxta pleural nodule.

1:58

That would be a lung reds two finding

2:00

of a juxta pleural nodule.

2:02

And the evidence for this is based on

2:04

large lung cancer screening cts

2:06

where patients have undergone multiple lung cancer screening

2:10

cts over years applying the criteria

2:12

for juxta pleural nodules

2:14

and showing that if you apply those criteria, um,

2:17

lung cancer was not missed in these large series.

2:20

So that's a benign finding.

2:22

A juxta pleural costal pleural based nodule

2:25

with a mean diameter under 10 millimeters that is solid.

2:28

So the end result for this patient is

2:30

that they have a long RAD four B finding

2:33

with a new just over 10 millimeter mean diameter nodule

2:37

meeting that eight millimeter size threshold

2:39

for new solid nodule in lung RADS four B.

2:42

This patient did ultimately undergo a VATS wedge resection

2:47

of this nodule, which confirmed on frozen section

2:49

that it was a cancer,

2:52

had a completion right upper lobectomy at that time.

2:55

And this was a moderately differentiated squamous cell

2:57

carcinoma in a lung cancer screening program.

3:01

Once we diagnose a lung cancer, it's important

3:03

that we do quality review, uh, to make sure

3:06

that we're practicing and detecting early lung cancer using

3:10

the best recommended guidelines as we have

3:12

with the lung rans interpretation schema.

3:14

This is something that is commonplace

3:16

and built in breast cancer screening programs.

3:20

So in this case we have a lung RADS four B

3:23

and a patient that is diagnosed

3:24

with an early stage lung cancer,

3:26

which is a very good outcome for the patient.

3:28

So we asked the question, well,

3:30

what about the prior lung cancer screening CT?

3:32

Was the interpretation correct?

3:34

Finding tiny lung nodules two millimeter, three millimeters,

3:39

particularly when they're central

3:40

or next to vessels,

3:42

is a very hard task on interpreting chest cts visually.

3:45

And it's also a very hard task for most

3:48

of the software tools

3:49

or AI tools that are out there in finding small nodules.

3:53

Most of the tools do pretty well when you get to nodules

3:55

of this size, but when you look at a nodule

3:57

that might be the same size as this little vessel,

4:00

it might be next to that vessel.

4:02

These tools don't do a great job.

4:05

Now, is it important to find every two millimeter nodule

4:08

because those aren't nodules we're going to intervene on.

4:11

So from a practical perspective, the fact that the tools

4:15

and readers have challenges with some of these tiniest

4:19

of nodules doesn't have clinical impact on

4:22

most patients in which they're found.

4:25

As we look at this nodule, we're gonna go back

4:27

to the prior CT

4:28

and say, you know, is there any suggestive evidence

4:31

of there being a little spot anywhere?

4:33

You know, can we learn from?

4:34

It is always something I like to apply.

4:37

So we're gonna look in the same area of the lung parenchyma

4:39

and see if we can see a little spot.

4:43

And we've had cts on this patient for many years.

4:46

So this is the most recent comparison that we had from

4:51

September, 2020 compared

4:53

to the October 21 screening exam on the left.

4:58

And if we look really, really closely,

5:00

and I had to scroll through this several times

5:02

to find this little spot,

5:04

there's a little tiny spot right here

5:07

and it's sitting right next to a vessel.

5:10

Very hard for a reader to detect

5:12

and very hard for software tools

5:14

or AI tools to detect as well.

5:17

Had this been detected, it would still be a long RADS two

5:20

because this nodule is under the size threshold

5:23

for calling a positive screen.

5:25

So this patient would've still had the same recommendation,

5:28

whether it was lung RADS one, no nodule

5:31

or lung rads two, a tiny nodule to come back

5:34

for annual screening in 12 months, which is what happened

5:38

and the standard of care was met.

5:40

If we look back at older cts, you know,

5:42

can we see this back in 2019?

5:44

Can we see it back in 2018?

5:47

I think sometimes you can go on back and look your darnedest

5:49

and try and find these on prior exams, and sometimes you can

5:53

and other times you can't.

5:55

When I looked at this exam back

5:56

To 2018, I was not able to find any evidence of

6:01

that tiny little, couple millimeter nodule

6:04

that would have been a lung rans two on the 2020 exam.

6:07

But good practice when you have a lung cancer diagnosed

6:10

and the lung cancer screening program is to go back,

6:12

look at your prior lung cancer screening cts,

6:15

look at your interpretations

6:16

and make sure that they met the lung red

6:18

interpretation criteria.

6:20

And if not, is there an opportunity for education

6:23

of the interpreting radiologists

6:25

to improve practice performance on behalf of our patients?