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Hey everybody, it's Mark.

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We're gonna continue on with our

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cardiopulmonary imaging, uh, curriculum.

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This topic is, uh, becoming a big topic these days.

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Usual interstitial pneumonitis.

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A lot of the clinicians refer to it as idiopathic

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pulmonary fibrosis, or IPF.

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So the reason it's becoming a bigger

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topic is because there are some, you

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know, it's, it doesn't respond to therapy.

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So I used to teach that all of these IPs and

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all of these fibrotic diseases are so confusing.

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There's UIP and there's everything else

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because most of the stuff from everything else

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responds to immunosuppressives or steroids.

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UIP does not.

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It's separate.

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So it's in the morphology.

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This is gonna be what?

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The peripheral lace-like or coarse reticular opacities.

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So that's what you would see in a radiograph,

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and the CT will show you what you'd see.

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So let's do a quick, quick, quick review.

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Um, you can always go back and check.

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One, but it's the imaging evidence of fibrosis.

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And there are five main imaging findings of fibrosis.

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You know, chronic ground glass, irregular

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visceral pleura is a big one, where it looks

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serrated; reticular opacities, which are lines,

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crisscrossing lines that don't branch; traction

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bronchiectasis, where the airways

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get pulled apart; and honeycombing.

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Now, it turns out honeycombing is the

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most important for the diagnosis of UIP,

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since that's the one that commonly has it.

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So, it's also one of the most difficult

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to actually see in imaging with confidence,

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because there are so many things that can

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look kind of similar, or it can be very mild.

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So, honeycombing—let's redefine it: three

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to 10 millimeters, shared cystic walls.

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There are walls.

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And they are right up against the pleura.

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This is important.

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They're right up against the pleura.

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If it's not on the pleura, that isn't

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honeycombing—right up against the pleura.

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And as it progresses, it goes

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from peripheral to central.

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So, it is possible to have a single layer, like

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here, of honeycombing and then others that are

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stacked up, that are a little bit more advanced.

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So, one of the things—again, honeycombing—if it's not

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right up at the pleura like this...

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Look, there are small holes with a

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little fibrosis and reticulation, but a

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lot of these do not contact the pleura.

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This is not honeycombing.

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It is something else.

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Small cyst.

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Again, honeycombing should be right

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up against the margin and they.

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Grow peripheral, uh, peripheral to central.

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So, you can have a single layer of honeycombing.

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Some people say you can't, but you

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can, and it's just much harder.

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This is a single layer of honeycombing, and

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this is where they're stacked up because

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it's a little bit more advanced here now.

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On the radiograph, what you'll notice, there'll be some

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peripheral, what I call lace-like coarse reticular,

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ies, little crisscrossing kind of lattice or net-like

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reticulation that almost always will reflect UIP.

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There's something called NSIP, nonspecific interstitial

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pneumonitis that does have a bit of overlap,

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and that's the main differential in many cases.

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Why does it occur peripherally?

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It's theorized smaller alveolar sizes.

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Maybe that's it.

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It probably is.

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I don't know.

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I do know that NSIP can also be peripheral,

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but it's more inconsistent, and NSIP tends not

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always tends to spare the subpleural region.

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That's a huge clue for you.

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Now, the basement membrane is exposed.

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In UIP injury, and therefore they tend

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to have a profound amount of hypoxia.

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NSIP fibrosis doesn't tend to expose

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the basement membrane, so their degree

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of hypoxia tends to be much less.

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So you could suggest things like A-D-L-C-O, and if it's

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really low in the setting of peripheral fibrosis, it's

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probably UIP if it's not too bad at all, and, and if

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there's any subpleural sparing, it's most likely NSIP.

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So this is a pathology you can see.

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How it's got this peripheral distribution fibrosis,

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honeycombing, it's nicely reflected on the radiograph.

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You get these little ant-sized kind

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of, uh, beehives of the honeycombing.

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When you get real close, you can see

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their thick reticular opacities that

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intersect forming these little holes.

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Okay.

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This would be a characteristic one.

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Does this person have fibrosis?

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Yes.

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They have irregular, visceral pleura.

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They have traction bronchiectasis.

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There's reticulation.

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All of these things are there now.

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Do they have honeycombing?

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Well, yeah.

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Look, three to 10 millimeters shared,

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wall thick, right up against the pleura.

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Some are single-layered, more recent,

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some are more advanced going peripheral.

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To central.

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What is the, a histologic that they

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find is called this fibroblastic foci.

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This thing right here, this is histologically

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one of the criteria that they use in addition

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to many others, ICU, um, heterogeneity of

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injury with some normal lung and some abnormal

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lung that's mild and some that's more advanced.

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This is where you can also see the basement

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membrane exposed, which profoundly affects.

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The oxygenation and DLCO tends to be very low.

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So for UIP, peripheral and BASAL

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is really an important distribution.

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It, if it isn't, you gotta be very careful about

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calling it UIP imaging evidence fibrosis, like we said.

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But honeycombing is the key.

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If you see honeycombing, it's probably UIP.

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You can suggest DLCO because it's

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really low with UIP as opposed to NSIP.

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Again, there are new medical therapies now

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'cause it's separate now, this is not in books.

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Every patient with anti-fibrosis,

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especially UIP, you make an active search.

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Like put it in your macro.

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Is there pulmonary hypertension?

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Are there any new nodules?

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And are there any new areas of ground-glass opacity?

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Always look for these three things on every patient

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with advanced pulmonary fibrosis, especially UIP.

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So 66-year-old male, UIP tends to occur in males.

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Most commonly, you'd see some reticulation here.

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There it is.

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It's peripheral basal.

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Not sure if there's honeycombing, but you'd know,

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okay, this person has some pulmonary fibrosis.

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Pulmonary artery.

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Looks a little big by the way, and then you

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see on CT, oh yeah, it's definitely peripheral.

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It's got all the fibrotic findings and it has.

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Honeycombing there is honeycombing.

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This is typical for UIP.

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Now, the most common etiologies for

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UIP: autoimmune diseases, drug toxicity.

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If we don't find anything, we call

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it IPF, progression of another ILD.

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If you have fibrotic NSIP and don't address

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what's driving it, it can eventually

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develop areas of UIP and asbestosis.

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I put a question mark.

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The vast majority of asbestosis fibrosis

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doesn't really look like UIP, but there

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are some that have asbestos and UIP.

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I don't know if it's the asbestos causing

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UIP or if it's just both happen to be there

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in the patient, but I, I left it there.

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So UIP, huge increase in lung cancer.

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Emphysema, bad emphysema.

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UIP.

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Who has more lung cancer?

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UIP, four to one.

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Okay.

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Four to one.

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So any new nodule in a patient with UIP

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is lung cancer until proven otherwise.

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So you've gotta look for, okay, this is a

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patient who's got, well, yeah, peripheral

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reticulation, you know, is there honeycombing?

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I don't know, maybe, but there's

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definitely architectural distortion.

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Whoa.

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Whoa.

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What?

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What's this?

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What's this?

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Oh yeah.

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That is suspect.

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This patient has pulmonary fibrosis that

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looks like UIP and I can't tell, but

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I think there may be a nodule in here.

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Any new nodule is lung cancer

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until proven otherwise on CT.

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That was a lung cancer.

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The other things you wanna be looking for, new

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ground glass, which suggests inactive deterioration,

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so-called, the old term was Hamman-Rich.

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This is people who have UIP.

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They're kind of slowly.

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Getting worse and then over about a two-month

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period of time, they just get a lot worse.

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And that's usually when you see this.

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This is a patient with UIP, single

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honeycombing, nothing there.

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Oh, new areas of ground glass without a lot of fibrosis.

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This is active deterioration.

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It reflects diffuse alveolar damage.

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The other thing you look for, pulmonary hypertension.

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Look at the pulmonary artery.

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Uh, it's bigger.

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When you develop these pulmonary hypertension,

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this often goes below the radar screen, but they're

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coming in more often to see their clinician.

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So you look for these three

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things, you gotta look for 'em.

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Now, every patient who's got possible fibrosis or

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chronic dyspnea or chronic cough, I think they should

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all have expiratory imaging in addition to inspiration.

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So when you look at this person, they have fibrosis.

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Okay.

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There is some peripheral, there's some

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traction bronchiectasis, centrally.

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It's not really a UIP, but then on, you see these

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darker areas here that get worse on expiration.

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They, they remain dark.

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That is actually characteristic for air trapping

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and air trapping in the setting of pulmonary

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fibrosis is strongly suggested for hypersensitivity,

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pneumonitis, extrinsic allergic alveolitis.

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Strongly.

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So you, that's the other thing.

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You look for another patient again,

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well that could be NSIP, right?

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But you get these areas of kind of darkness

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that were accentuated on expiration.

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So this is not really so-called UIP.

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This is extrinsic allergic alveolitis with

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associated fibrosis and maybe even

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some areas of early UIP honeycombing.

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Remember, if you don't address

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other ILDs and they progress, they can

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eventually progress to a UIP pattern.

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Okay.

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All right.

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Reticulation, how about this one?

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Lots of fibrosis here.

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Lots of fibrosis.

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But notice the subpleural area, it's spared.

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You still see that irregular, visceral

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pleura, but there's sparing of it and

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I'm, you know, is that honeycombing?

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No, it's not touching the wall.

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Is traction bronchiectasis, look at that.

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Subpleural sparing also has a bronchovascular

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distribution radiating out from the hilum.

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Is this UIP?

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No.

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These are really characteristic

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imaging findings for fibrotic NSIP.

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That would most likely be the diagnosis here.

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Probably an autoimmune disease, maybe drug toxicity.

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I. Another patient, 57-year-old, female.

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Female.

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Well, UIP is more often male, but

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you know, we'll keep looking.

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There's imaging evidence of fibrosis.

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There's some ground glass, chronic ground glass,

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you know, literally irregular, visceral pleura.

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Don't see any honeycombing, plus or minus,

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whether there's maybe some air trapping.

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So what can you do?

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You could suggest an expiratory,

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see if there is air trapping.

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And you could also suggest DLCO if the

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DLCO is like, you know, 75, 80%, it's probably

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NSIP chronic, uh, extrinsic allergic alveolitis.

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If the, uh, DLCO is like 60 with this, you go,

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ooh, well it could be UIP I guess just early.

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So I want to give a shout out for the radiology.

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You can't just say it's pulmonary fibrosis, nonspecific

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consult, pulmonary, no pathology is not the gold

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standard, or with this disease of ILD, imaging is vital.

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It relies strongly on imaging, so you gotta be able

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to be a little bit more discerning in your reports.

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It is recommended by the Fleischner

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Society White Paper from 2017.

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Good paper by the way, that if you

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encounter pulmonary fibrotic diseases,

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that you use this sort of terminology.

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The typical UIP pattern is that, you know, basilar,

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reticulation, honeycombing, traction bronchiectasis,

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and no features that are inconsistent with UIP.

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Okay, if you have all of these things, but no

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honeycombing, you'd say, well, it's probable

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UIP, but you know, it could be fibrotic

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NSIP too, you know, suggested DLCO,

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or if the pattern is indeterminate, like.

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You know, I'm, I don't know

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what it's I, and that's okay.

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I still say that.

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Or it's consistent with something

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else like, oh, there's air trapping.

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This is likely chronic hypersensitivity

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pneumonitis.

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So we'll finish with this.

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For this patient, what would your impression say?

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Determine a pulmonary fibrosis cell pulmonology?

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No.

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Don't anyone pick that.

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Fibrosis likely represents drug toxicity

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or connective tissue disease pathology?

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No, because drug toxicity and connective

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tissue disease are not pathology.

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They're etiologies; imaging typical for UIP.

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Well, yeah, there's honeycombing.

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It's peripheral.

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It's basilar.

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There's all the evidence of fibrosis.

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Yeah, I'd go with that.

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Findings probable for UIP vs.

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versus NSIP; suggest DLCO.

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Well, you know, I think it's three.

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I would just come down hard on it.

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If you said four, that's okay too.

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All right.

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Because at least it'll be found out.

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It'll be figured out.

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So that's the summary of UIP.

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It's a big topic.

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I've tried to just hit the highlights.

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It, it requires a different treatment.

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Radiology is vital to the diagnosis, so

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you have to be able to kind of discern when

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it's UIP or not the best of your ability.

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Pathology is not the gold standard.

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Honeycombing is key along with

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peripheral distribution and a low DLCO.

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You reported out as typical, probable, or

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indeterminate or consistent with something else,

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and always make an active search for nodules,

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which will be cancer until proven otherwise.

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Pulmonary hypertension and new ground glass.

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With that, thank you very much.