0:00

The most common type of lung nodule found on lung cancer

0:03

screening cts is a solid lung nodule.

0:07

The preponderance of lung cancers that we find

0:09

through early detection

0:10

with lung cancer screening come from solid nodules.

0:13

Whether they're smooth lobulated speculated

0:16

or have other morphologies,

0:19

heart solid nodules individually are

0:21

more likely to be cancer.

0:22

When found, they just represent a much smaller percentage

0:26

of all the nodules that we come across on lung cancer

0:28

screening cts.

0:30

The way I like to think of it is that the lung is subject

0:34

to our day-to-day inhalation of many things.

0:37

They could be occupational exposure or dust.

0:40

There can be issues that happen

0:43

to the lung parenchyma leaving nodules

0:45

or areas of scarring related to prior infection.

0:48

So a lot's going on in your lungs every day

0:50

with every breath, and sometimes it leads to the formation

0:53

of small solid nodules.

0:55

How do we approach these nodules?

0:58

In lung rads, we categorize them by size

1:00

and growth into categories two through four x

1:04

with the highest category having the highest

1:06

risk of being malignancy.

1:07

You'll notice that if we look at solid nodules,

1:10

they go from six to millimeters

1:12

and less being lung rads two at baseline

1:15

or new four millimeter nodules.

1:17

If a patient is coming

1:18

for their subsequent annual screening CT

1:21

under six millimeters of baseline for category two, six

1:24

to eight millimeters for category three, eight

1:27

to 15 millimeters for four A and 15 millimeters

1:30

and larger for four B.

1:32

Now as familiar as I am with lung Rads

1:34

and having started the Lung RADS committee at the American

1:37

College of Radiology, I always find it very important

1:40

to have the lung rads information at my fingertips

1:43

to make sure I am appropriately using the size categories.

1:46

No matter what nodule type I'm looking at.

1:49

You'll notice that the table also has

1:52

volumes next to the diameters.

1:54

So if you're using volume diameters in your practice,

1:57

which many practices are starting to do

1:59

and it's common in some European countries,

2:03

it also translates the size into volumes for you.

2:07

With increasing category number comes higher risk of cancer,

2:11

and so we go from negative screens, lung RADS two

2:14

with under six millimeter nodules of baseline

2:16

or new under four millimeter nodules, two six months ct.

2:21

Follow-up when we get to the next category of size

2:24

and then three month follow-up all the way up

2:26

to a diagnostic assessment when we get

2:28

to these largest nodules, 15 millimeters

2:31

or larger on the first CT

2:33

and new eight millimeter larger nodules on subsequent cts.

2:38

One thing that's important to mention within

2:41

the solid nodule category are jux pleural nodules.

2:45

Initially in lung rads we had described the nodules

2:49

that are peri fial, that is nodules like this,

2:52

that are triangular

2:54

or angular in shape that sit along the fissures, the minor

2:57

or major fissures

2:58

Bilaterally, and if they're under 10 millimeters,

3:02

angular triangular, len deform and smoothly marginated.

3:05

We consider those to be benign in pulmonary lymph nodes.

3:09

How do we know that? Because large series have been

3:12

published from lung cancer screening studies,

3:14

which are people who are at high risk for lung cancer

3:18

tracking car fist nodules over time across annual screening

3:22

exams within the same patient,

3:24

and these nodules have been proven

3:27

to be benign in these large series.

3:29

So again, under 10 millimeter, mean diameter solid

3:32

with smooth margins and either their oval L deform

3:35

or triangular and shape.

3:37

These are considered benign per fist nodules.

3:40

We've extended this same application to new information

3:43

that's been published on costal, pleural based nodules,

3:46

diaphragmatic pleural nodules

3:48

and mediastinal pleural nodules.

3:50

So basically every pleural surface

3:52

of the lung you can apply these criteria two.

3:55

So these per mediastinal locations,

3:58

the cosal pleura along the ribs

4:00

and the diaphragmatic pleura, the same application

4:04

of nodules smoothly marginated under 10 millimeters in mean

4:07

diameter lent deform obtuse angles to the pleural surfaces.

4:13

These are the characteristics of jux pleural nodules

4:16

outside the fist surface.

4:18

By making these lung RADS two lesions, we reduce the number

4:22

of positive screens that would be called lung rads three

4:25

and reduce the number of false positives, if you will,

4:28

by correctly calling these benign int pulmonary lymph nodes.

4:32

Category two in lung rads,

4:35

these are not juxta pleural nodules while they

4:38

touch the pleural surface.

4:40

This one has an acute angle

4:41

with the pleural surface indicating its epicenter didn't

4:44

startle along the pleura.

4:45

It started in the lung parenchyma.

4:47

This nodule also has acute angles

4:50

with the cosal pleural surface and it's lobulated.

4:53

And then this one has both solid

4:56

and ground glass components.

4:58

Juxta pleural nodules do not have ground glass components,

5:02

so these characteristics, even though they touch the pleura,

5:05

are not juxta pleural nodules.

5:07

So appropriate to know what is and what is not.

5:11

Juxta pleural nodule when categorizing them.

5:13

All of these would be category long rats, four A

5:16

by their size and consistency.

5:19

So that's how we approach solid nodules

5:21

and the long rats categories

5:22

that we'll be applying while looking at individual cases.