0:00

Let's take a look at how I approach the interpretation

0:03

of a lung cancer screening ct.

0:05

This is my basic layout with my axial mips.

0:08

On the top left my lung soft tissue

0:11

and bone windows on the top row.

0:14

And on the bottom I have my scout image, my coronal

0:16

and sagittal multiplanar reconstructions available to me.

0:20

And I have one of our artificial intelligence methods open,

0:24

which tells me something about the lung tissue

0:27

and the amount of emphysema that there might be in the exam.

0:30

We have a second tool available

0:33

that is a lung nodule detection tool, which I can also view

0:37

as I'm interpreting the images.

0:39

I can see it as a thumbnail at the bottom of the screen.

0:41

And it shows me that no nodules four millimeters

0:44

or larger were detected on this exam.

0:46

But I can use this that if there are nodules to scroll

0:49

through each individual exam, how it was measured

0:52

and what slice an image number it was on so

0:55

that I can readily get to those nodules.

0:57

Um, helping me in during my interpretation.

1:01

So primarily I'm gonna be viewing the lung windows

1:04

and I'm gonna be looking for pulmonary nodules.

1:07

Things that we see in the background of the lung parenchyma

1:09

that do not connect with pulmonary vessels.

1:12

They're obviously a lot easier to see around the periphery

1:15

of the lung where the vessels are smaller

1:17

and you have more aerated lung tissue.

1:19

They can definitely be hard

1:20

to find when you're looking at the central bronchovascular

1:23

structures, which make the central areas

1:26

of the lung much busier.

1:27

And so nodules that are juxta vascular,

1:29

particularly in the central portion of the lung, is one

1:33

of the blind spots that I always pay extra attention to

1:36

as I'm looking at the branching bronchovascular bundles

1:39

and making sure that the vessels themselves are smooth

1:42

with no, uh, focal nodularity

1:44

that might be hiding along the edge of a pulmonary vessel.

1:48

I'm also looking for underlying lung disease patients

1:51

who have uh, pack your history of cigarette smoking

1:55

that makes them eligible for lung cancer screening

1:58

commonly have emphysema.

1:59

So I'm looking for small spots of low density

2:02

that are usually upper lobe predominant in a patient

2:05

with smoking related central ular emphysema.

2:07

And as you can see here, we have discreet areas

2:10

of low density scattered throughout the upper lobes.

2:13

Very mild and extent well under 5%

2:16

of the total lung volume up here in the upper lobes.

2:18

That's early central lobular emphysema.

2:21

And as we scroll down the lungs, you notice

2:23

that the emphysema pretty much goes away.

2:26

Emphysema that is central lobular

2:28

is usually an upper lobe predominant process related to

2:31

where cigarette smoking is inhaled

2:33

and damages the lung parenchyma

2:35

and where you have the least ventilation to clear out some

2:38

of the particulate matter.

2:40

We're also gonna look at the small airways

2:42

because patients with smoking related lung disease not only

2:45

get emphysema as one form of COPD,

2:48

they get small airway disease.

2:49

So we're gonna look at the bronchial walls to look

2:52

for bronchial wall thickening or OID impaction.

2:55

And these are thin just barely discernible bronchial

2:58

Walls, whether you're looking them in long axis

3:01

or whether you're looking them in cross-section

3:04

as the round airways in general to look for dilated bronchi

3:08

or bronchiectasis.

3:10

We do not expect to see any bronchi

3:12

that are normal in the peripheral several

3:14

centimeters of the lung.

3:15

So if you see any bronchi coming close

3:18

to the pleural surface, particularly in the anterolateral

3:21

lung, that would be considered a mildly dilate

3:24

in a bronchiectasis.

3:25

But we also compare the diameter of the bronchi

3:28

to the adjacent arteries as the arteries

3:30

and bronchi run in pairs.

3:32

And when the bronchus becomes bigger than the adjacent

3:35

artery, that is a criteria for dilated airways.

3:38

And then lastly, patients with a history

3:41

of cigarette smoking also can get interstitial lung disease,

3:44

whether it's respiratory bronchiolitis in their upper lobes

3:48

or an increased risk of interstitial uh,

3:51

lung abnormalities such as pulmonary fibrosis

3:53

or squam of interstitial pneumonitis.

3:55

So we do wanna pay careful attention not only for nodules

3:58

but for lung disease.

4:00

We'll of course look at all of the other structures

4:03

that are here on a chest CT done for lung cancer screening,

4:06

not just the lungs, which is our focus

4:08

for the early detection of cancer.

4:10

But just like you read any chest ct, we're gonna look

4:13

through the cardiovascular structures of the mediastinum

4:16

aorta for aneurysms and calcification.

4:19

The coronary arteries, you can see they're very noisy,

4:22

but calcium usually pops up pretty well despite the image

4:24

noise, overall cardiac size, structure,

4:27

shape and pericardium.

4:29

And of course we're gonna get into some

4:30

of the tissues in the upper abdomen

4:32

where it gets much noisier.

4:34

So we usually put a caveat on a report

4:36

that within the limits of this non intravenous contrast,

4:39

low dose examination of the upper abdomen as normal

4:42

or describe the findings that we might see

4:45

looking at the sagittal images as particularly important

4:48

to look at the bones.

4:50

Um, we're gonna measure bone mineral density

4:52

by putting a cursor on the L one vertebral body to try

4:56

and identify early osteopenia or osteoporosis.

5:00

And as I mentioned, we're going to use some

5:02

of our artificial intelligence tools

5:03

that are gonna back me up

5:05

and say, Hmm, this tool didn't find any nodule.

5:07

So it's a support to me as the reader.

5:09

It's not the primary reader.

5:11

And if it has nodules identified with location

5:14

and diameter, I'm gonna verify those diameters

5:16

and verify that they indeed are lung nodules.

5:20

So that's how I generally approach the interpretation

5:22

of a lung cancer screening ct,

5:24

focusing primarily on the lungs lung nodule detection

5:27

with the use of an artificial intelligence tool to help

5:30

and also to help get some of

5:32

that information directly into our PowerScribe radiology

5:35

reports through an integration

5:37

of this data into the PowerScribe fields, as well as

5:40

how I can look for lung disease in the presence of emphysema

5:43

and bone mineral density.

5:45

Important that we look at all the structures on a lung

5:48

cancer screening CT just like we do every chest ct

5:51

to the extent you can see them within the amount

5:54

of image noise that you have at hand.