0:00

All right, let's look at this case together.

0:02

So look at all this honeycombing,

0:03

beautiful honeycombing here.

0:05

And so if we were just scroll through,

0:07

look at all this honeycombing, we would think to ourselves,

0:09

oh, well maybe this is just a UIP pattern.

0:12

And I think in isolation that's what we would say.

0:15

But if you have your thinking cap on

0:17

and look carefully, they're all also areas

0:20

of superimposed mosaic attenuation on this

0:22

inspiratory phase ct.

0:24

So all these dark areas that are demarcated by the edges

0:28

of secondary pulmonary loles

0:31

and it's bilateral, it's not just at the lung bases,

0:33

it's also in the upper lobes as you can see here.

0:35

So that's funny. So that feels like air traffic to me.

0:39

And so we look at the expiratory phase CT as we scroll

0:42

through on on the expiratory phase ct.

0:44

We see that indeed many of these areas of

0:47

mosaic attenuation on inspiration represent areas

0:50

of air trapping.

0:51

Some of them don't. Some of them are probably just areas

0:53

that are just relatively hypo dense,

0:55

but many areas are air trapping.

0:57

And especially in the upper loads,

0:58

when you see upper lobe air trapping, you should start

1:01

to actually really think about alternative diagnosis to UIP.

1:05

So this also has this finding

1:08

of significant anterior upper lobe fibrosis.

1:10

You see that all those, those honeycomb cysts.

1:14

And if you really think about it,

1:16

this is actually a nice example

1:18

of something we would at least

1:20

entertain calling the exuberant honeycombing sign.

1:24

Remember in that lecture there was that additional slide

1:26

that we put in there as as a little little pearl.

1:29

And so this patient though,

1:31

I think overall the pattern would be most consistent

1:33

with fibrotic hp.

1:35

So distribution is essentially diffuse

1:38

both in the EO and zonal plane.

1:40

A lot of fibrosis here. Uh, significant air trapping.

1:43

There's some ground glass opacity as well.

1:44

So fibrotic HP pattern.

1:46

But remember especially in the, the setting of fibrotic hp,

1:50

sometimes the fibrotic HP pattern is actually not due

1:54

to hypersensitivity pneumonitis.

1:55

So there is some data that shows

1:57

that if you have a fibrotic HP pattern,

2:00

almost never is it U-I-P-I-P-F.

2:03

So that's helpful, right? Because remember we're working off

2:05

the U-I-P-I-P-F model, that schema.

2:08

And so this, it's helpful that when you see this pattern,

2:11

you can be confident that it's not U-I-P-I-P-F,

2:14

but you can't be 100% confident.

2:16

That's actually due to hypersensitivity.

2:18

Pneumonitis about 20% of fibrotic HP cases

2:22

or patterns on ct.

2:24

If you see that pattern, actually 20%

2:26

of the time it's gonna be due to connective tissue disease.

2:28

And this case we actually see manifestations

2:31

of UIP in the setting of CTD, right?

2:34

Those findings that we mentioned before.

2:35

So exuberant honeycombing sign,

2:37

and then the anterior upper lobe sign.

2:39

So if we really were thinking hard

2:42

and we're trying to like dig deep

2:44

and trying to consider all options, we would've said, okay,

2:46

this likely is connected tissue disease,

2:49

though there is a fibrotic HP pattern.

2:51

And so, uh, this is not a simple pattern,

2:53

this is very complex,

2:55

but unfortunately sometimes you encounter cases like

2:57

this. And

2:58

So what I do when I see tough case like this is always

3:02

to take a step back, take a step back

3:04

and approach it from the most logical,

3:08

practical scammer that I have.

3:09

And that's that practical approach that I talked about.

3:12

Okay.