0:00

Let's look at this lung cancer screening case together

0:03

as there are lots of findings both in the lungs,

0:06

in the mediastinum, as well as incidental findings.

0:08

So lots of lots of things to look at.

0:10

And sometimes when there are lots of findings, it's easy

0:13

to get distracted and maybe miss other findings.

0:16

So important domain concentration

0:18

and a systematic approach to interpreting these exams.

0:21

So if we start focusing mostly on the lung windows on the

0:25

left, we first come across a tiny little nodule.

0:27

This would fall in the lung Rads two category size threshold

0:33

and keep scrolling through the lungs.

0:35

And we can use our MIPS

0:37

to make little nodules stand out a little bit better.

0:41

And we can find a number of these tiny nodules like this

0:44

that are gonna be in the lung rants two category.

0:49

We see a calcified granuloma right there, bright white,

0:53

calcified seen on the soft tissue windows over there on the

0:56

right hand side there it's,

1:03

and then we see a nodule adjacent

1:05

to the central left hilum right here.

1:08

Soft tissue density nodule smoothly, marginated

1:11

by size criteria

1:13

that's gonna make it into the four B category.

1:17

And when I'm looking at the left hilum,

1:19

something doesn't really appear quite right, particularly

1:22

as I'm looking in the soft tissue

1:24

and as I see the main pulmonary artery,

1:26

the left pulmonary artery

1:28

and the branch that goes down into the lower lobes here.

1:31

But as I go upwards, instead of it tapering,

1:35

it gets rounder back here.

1:37

And this is a very hard finding.

1:39

Sometimes on a non-contrast, low dose CT

1:42

pilar structures can be difficult

1:44

to value without intravenous contrast.

1:47

But when we have a nodule, it's always important

1:49

that we look for draining lymph nodes.

1:51

So it heightens your sensitivity

1:53

and we look at the shape of that pulmonary artery instead

1:55

of tapering as it branches into the upper lobe.

1:58

It's actually getting rounded in more mass like

2:00

so we've got a nodule and a large lymph nodes.

2:04

You know, we've got some evidence of small airway disease.

2:07

The small airways are very thick

2:08

and some of the lumens are very, very tiny.

2:11

I usually describe it as small airway channels

2:13

or diminutive airway channels with the wall thickening.

2:16

And a few of them, there's a little bit of mucus plugging.

2:18

So there's evidence of small airway disease, phenotype

2:23

of obstructive pulmonary disease.

2:25

We have more small nodules like this one here

2:28

and a number of nodules here in the preferred,

2:31

the right lung smoothly marginated.

2:34

There's some investigation going on about other kinds

2:37

of benign pulmonary nodules

2:39

where you can see a little thin pleural tag.

2:42

And you have a bi convex nodule like this

2:45

where you have a triangular shaped nodule, again

2:47

with a little tiny plural tag extending the pleural surface

2:50

about whether or not we can call those benign in

2:52

pulmonary lymph nodes.

2:54

And juxta plural don't have the answer yet on that,

2:56

but that's something that's being looked at.

2:59

And on the soft tissue windows, a little bit

3:03

of aortic arch calcification, there's a lot

3:07

of epicardial fat.

3:08

We can see it even up here, allowing the ascent

3:11

and UTA main pulmonary artery and in the atrial septum

3:14

and overlying the right ventricle.

3:16

So that lipomas hypertrophy of the atrial septum

3:18

and increased epicardial fat

3:21

had a moderately sized tidal hernia there.

3:23

Small to moderately sized a lot of other findings.

3:28

So what we're left with is

3:30

looks like a category four B lung rads nodule next

3:34

to the left hilum probably within large lymph nodes here,

3:37

given the non tapering of the pulmonary artery.

3:40

And so this patient is a 65-year-old

3:43

who has a hundred pack your history of smoking

3:45

and has a known history of COPD with a lung rant four case.

3:50

This patient did subsequently undergo evaluation,

3:53

and I wanna show you their pet ct.

3:57

So this was a pet CT done shortly

3:59

after the lung cancer screening ct.

4:02

We've already have a lung nodule

4:04

and a large hial lymph nodes.

4:05

Certainly a heightened concern about cancer spread.

4:09

And I like to go back and look at these when we've had

4:11

abnormal lung cancer screening cts again

4:13

to do my own quality control on.

4:15

Are we finding everything we possibly can?

4:18

Can I increase my ability to detect things

4:20

that can sometimes be challenging on low dose ct?

4:24

So we see that nodule

4:26

and the lymph nodes that we saw readily on the

4:30

left side, but we also have a spot here on the right side.

4:34

So wanting to learn more, I go back

4:37

to the lung cancer screening ct and I look in the same area,

4:41

and I think this is a very subtle finding,

4:44

is if you're following the right main bronchus

4:46

and the right upper low bronchus here, and it comes anterior

4:50

and it bifurcates nice smooth margining bronchus,

4:55

this bronchus here, instead of gradually tapering,

4:59

a branching more abruptly gets narrow.

5:03

And there's a concavity here

5:07

where instead of the lumen pooching outwards

5:11

and being convex, it's concave inwards.

5:15

So there's something sitting in the bronchus.

5:18

And if I look further, if this is a pulmonary

5:22

vascular branch, a pulmonary vein right here,

5:24

what's this extra little

5:26

rounded structure sitting right here?

5:27

I can see the edge of it here,

5:29

and I can see it probably flattening a bronchus back here.

5:32

This is a really hard call to make prospectively, I think,

5:35

on a lung screening CT without contrast in a patient

5:41

trying not to be distracted for other findings,

5:43

clearly having positive findings on the right side.

5:45

These types of central findings, things

5:48

that are a long bronchovascular bundles

5:51

and consecutive with vascular structures

5:53

can be very, very hard.

5:54

It's one of the blind spots on non-contrast

5:57

Chest CT in particular is things that are

5:59

around the central bronchovascular structures.

6:02

This patient did subsequently undergo bronchoscopic biopsy

6:06

bilaterally, and both

6:08

of these were small cell carcinomas overall.

6:11

The stage of small cell cancer was limited instead

6:14

of extensive stage because the cancer was confined

6:17

to the chest and had not spread on further staging

6:20

at the time of treatment.

6:22

And this patient has done well

6:24

with treatment in the several years since their diagnosis.

6:27

But this just points out, there are some things

6:28

that are straightforward for us to find.

6:30

We can see nodules surrounded

6:32

by lung tissue without contrast, it's harder

6:35

to evaluate the central bronchovascular structure.

6:37

So we rely on things like knowing our anatomy, looking

6:41

for vessels that are tapering versus not tapering

6:44

for something that might be a mass

6:45

or lymph nodes next to it.

6:47

And then small things like this along the bronchovascular

6:50

bundles can be very hard for us to find.

6:53

We try and scrutinize the small airways,

6:55

but as you're scrolling through the examinations,

6:57

just a quick hop of a couple images

7:00

and you go from airway looking normal

7:02

to airway looking normal again.

7:04

So it's important to do quality control.

7:07

It's important to learn from patients who are diagnosed

7:10

with lung cancer to improve

7:12

how we perform when we are interpreting lung cancer

7:14

screening cts so

7:16

that we can work towards identifying the most subtle

7:18

findings and the early evidence of lung cancer.