0:00

Alright.

0:01

And that brings us to central lobular nodules.

0:03

So literally nodules along the center

0:06

of the secondary pulmonary lole.

0:09

And so this is what it looks like on this diagram.

0:11

So again, the center, so you're gonna have relative

0:13

subpleural sparing those other two patterns

0:16

that we talked about, the random pattern

0:17

and the per lymphatic pattern.

0:20

Both of those patterns,

0:21

you're gonna see nodules along the subpleural portion

0:23

of lungs and lung fissures in random.

0:26

It's just 'cause it just doesn't care.

0:27

It just goes wherever it wants.

0:29

And with para lymphatic nodules, it's

0:30

'cause the subpleural portion lung has a lot

0:32

of lymphatics concentrated there.

0:34

So that's where you're gonna see the subpleural nodules.

0:36

With central loor nodules, again,

0:38

you're gonna get this relative subpleural sparing

0:40

because by definition they don't wanna

0:42

involve that portion of lung.

0:43

Here's an example of central lobular ground glass nodularity

0:46

where we see this beautiful relative

0:48

subpleural sparing here.

0:49

Ignore the conent ground.

0:50

Glas opacity more anteriorly, let's ignore that.

0:52

But note posteriorly

0:54

and laterally there is clearly subpleural sparing.

0:58

And these central library nodules,

0:59

they seem relatively ordered.

1:01

You guys see that? How like,

1:04

so these are more like polka dots.

1:06

So with central library nodules, I've seen people

1:09

mistaken these for random nodules.

1:11

But remember random means entropic, right?

1:13

They literally mean random. And so in random nodules,

1:17

some are gonna be closer together, some may be further apart

1:19

with central loin nodules

1:20

because they respect the underlying secondary pulmonary

1:23

lobular anatomy.

1:25

They have an order to them.

1:26

So relatively even space like this.

1:29

So you see that, you see the relative subor sparing,

1:31

central lober nodules.

1:32

So it's very, very helpful. So that's, that's important.

1:34

So this is sort of the, the pitfall

1:36

that I've seen people getting central lobular nodularity

1:39

and random nodules mixed up.

1:42

Unfortunately the differential diagnosis

1:44

for central li nodules can be quite broad as we see here.

1:47

But what's quite helpful to remember is that

1:50

because most of these things got there through the airway,

1:52

these, that's why they're in the

1:54

central ular core structure.

1:55

The most common things that give you central lior nodules in

1:58

the acute setting are gonna be pneumonia and aspiration.

2:02

So if you see tree and butt opacities as a subset

2:05

of central Lior nodularity, you should be quite thankful

2:07

because now you can be very confident that the nodularity

2:11

that you're seeing is either due to pneumonia or aspiration

2:15

or a disease that causes bronchiectasis.

2:17

Well over 95% of the time it's gonna be due to one

2:21

of those three things.

2:23

So here's the patient with adenovirus pneumonia.

2:25

Look at this beautiful branching,

2:27

central lobular nodularity.

2:28

That's why you get the relative subpleural sparing here.

2:31

Beautiful branching morphology.

2:32

This is the tree

2:34

and bone morphology means there's something in the airway.

2:36

There's schmutz or fluid

2:38

or you know, something in the airway, whether pu you know,

2:40

but something, some debris in the airway,

2:42

which is manifesting with this CT pattern.

2:45

And so first we think about pneumonia,

2:47

then we think about aspiration,

2:48

and then we look for bronchiectasis.

2:50

'cause this could also be a manifestation of inflammation

2:53

or secondary infection in someone

2:55

with chronic bronchiectasis. Here's an example of treat

2:58

By nodularity and somewhat aspiration.

3:00

So again, beautiful example here, these branching areas

3:03

with subpleural sparing.

3:06

I think I'd be remiss if I didn't actually mention this.

3:08

So remember,

3:10

based on our secondary pulmonary lobular anatomy discussion,

3:14

what travels with the small airways into the center

3:16

of the secondary pulmonary lole,

3:19

we get small pulmonary arterials, right?

3:21

So stuff that travels through the,

3:24

the vasculature can also cause tri bud nodularity,

3:27

though usually it looks a little bit different,

3:30

looks a little bit more fine, as in this case,

3:32

this case was shared with me by Dr.

3:35

Ted Cardoso from Tampa Bay, Florida.

3:37

And so we see this diffuse tree blood nodularity

3:40

all throughout the lungs.

3:41

And so this is a case

3:42

where it's not this patient came into the ed,

3:44

but this patient, uh, didn't have pneumonia aspiration,

3:47

which would be the first thing you should be thinking about.

3:49

This patient had a history which actually points to

3:52

what the diagnosis is.

3:53

And so again, there's just a reminder

3:55

as a chest radiologist, if you have a very interesting chest

3:57

case manifestation like this, it really is helpful

3:59

to look into the EMR or just to call the clinician.

4:02

'cause a lot of chest imaging to make the diagnosis you need

4:06

to discuss it with the clinical team.

4:08

And so this patient was injecting things

4:12

that they shouldn't be injecting into their veins.

4:14

And so if you take stimulants,

4:16

and this is actually more common in Seattle,

4:18

when I was a resident there,

4:19

people would, would take ritalin.

4:21

So oral ritalin, which are filled with all sorts of things

4:23

that are not meant to be injected into your vein.

4:26

So things like talc, methyl cellulose,

4:28

things are non soluble.

4:29

They, they just won't dissolve.

4:30

So they're just like solid particulate

4:32

and you inject it into your veins.

4:33

What happens? The veins take it back into your IVC

4:36

or into your, your SVC, depending on

4:38

where you injected it goes into your heart.

4:40

And then from your heart, it sends down to the,

4:42

into your right aum,

4:43

into your right ventricle, into your pulmonary artery.

4:45

And then the pulmonary arteries kind

4:47

of branch, branch, branch, branch, branch.

4:48

And eventually those little particles

4:50

that are non soluble will get stuck in your small pulmonary

4:53

arteries and they cause a localized ulous reaction.

4:57

And so some of that maybe can be resorted,

4:59

but a lot of it's just gonna be there

5:00

and cause this chronic lung inflammation.

5:02

And the more they do it, the more it's gonna accumulate.

5:05

It's, it is like I had this, uh,

5:06

awesome attend from in Kentucky who would talk about, uh,

5:09

medical education being like throwing

5:11

poop at a, a chicken wire, right?

5:12

So the first time you throw a little poop at chicken wire,

5:14

like not much of it sticks, but as you throw more

5:16

and more poop on that chicken wire

5:17

because you have this base of education of knowledge,

5:20

you start to build more and more.

5:21

It's sort of like that. So the more you do it,

5:23

the more particulates are stuck there

5:25

that capture more particulate.

5:27

And then that leaves to this sort of unending cycle

5:29

of chronic inflammation with the lungs.

5:31

And a very common will manifest

5:33

with either central lobular nodularity

5:35

or this beautiful tree and button nodularity as we see here.

5:39

So this is, we call it excipient lung,

5:43

but bottom line, more than knowing the name,

5:45

it's more important to know why we can see these things in

5:48

patients who use illicit drugs intravenously, things

5:51

that usually you take orally, usually oral stimulants,

5:54

but they, they crush it up put into like a,

5:56

a slurry usually just tap water.

5:58

So usually not even hygienic

5:59

and they inject it intravenously.

6:00

So I, my public service

6:02

announcement here, don't, don't do drugs.

6:03

Especially not those drugs.