recognize airspace

8/8/2019 Recognize Airspace

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Recognizing

Interstitial VersusAirspace Disease

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All Images Retain Their Original Copyrights

William Herring, M.D. 2003


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Why learn the difference?

Many times these patterns overlap But frequently, recognition of one

or the other helps with the

Differential diagnosis


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Parenchymal Lung Disease

Two Major Types

Alveolar (air space)

Interstitial


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Airspace Disease

Soft-tissue opacities

With hazy and indistinct margins

Tend to respect segmental or

lobar boundaries May contain air bronchograms


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Air Bronchogram

Bronchi usually not visible

Walls are thin, they contain air, are surrounded

by air

When something of fluid density fills

alveoli, air in bronchus becomes visible

Pulmonary edema fluid

Blood

Gastric aspirate

Inflammatory exudate


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Air Bronchogram

The visibility of air in the bronchi becauseof surrounding airspace disease is called

an air bronchogram

An air bronchogram most often a sign of

airspace disease


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The black branching

structures are theresult of air in the

bronchi, now visible

because density

other than air

surrounds them (in

this case it isinflammatory exudate

from a pneumonia).


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Pulmonary edema

This disease is

fluffy and indistinct

in its margins, it is

confluent and

tends to be

homogeneous. In

both upper lobes,

you can see air

bronchograms.

This is an alveolar

(airspace) disease,

in this case

pulmonary edema

on a non-cardiogenic basis.


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Common Airspace Diseases

Pneumonia inflammatory exudate

Pulmonary edema edema fluid

Pulmonary hemorrhage blood

Aspiration gastric juices


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Aspiration pneumonia at both bases

Airspace Disease


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Interstitial Lung Disease

Now referred to as infiltrative lung disease

Discrete particles of disease Inhomogeneous

Doesnt respect lobar boundaries

Usually no air bronchograms

Made up of lines (reticular) or dots

(nodular) or both (reticulonodular)


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Interstitial disease discrete,

inhomogeneous, no air

bronchograms

Airspace disease fluffy,

indistinct, homogeneous,

contains air bronchograms

Interstitial versus Airspace Disease


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Common Interstitial Lung Diseases

Cancer1 or 2 Sarcoidosis

Cystic fibrosis

Asbestosis


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Right upper lobe mass is

a bronchogenic

carcinoma. It is sharply

marginated, relativelydiscrete, contains no air

bronchograms. It began

in the interstitium of the

lung.

Bronchogenic carcinoma large cell


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Interstitial Diseases

Examples of mostly nodular patterns

Hematogenously disseminatedmetastatic disease, e.g. renal cell ca

Silicosis

Miliary tuberculosis


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This CT of the

chest shows

thickened

bronchial walls

with extensive

dilatation of the

bronchi (bronchishould be

smaller than

their

accompanying

blood vessel).

This interstitial

disease is Cystic

Fibrosis.Cystic Fibrosis


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This is a diffuseinfiltrative

(interstitial)

disease that is

composed

primarily of lines(reticular disease).

Examples of

mostly reticular

disease include

idiopathic

pulmonary fibrosis

and eosinophilic

granuloma.Idiopathic pulmonary fibrosis


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Eosinophilic granuloma of the lung

Pulmonary interstitial edema

Idiopathic pulmonary fibrosis

Rheumatoid lung

Interstitial Diseases

Examples of mostly reticular patterns


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Interstitial lung disease

with coarse, criss-

crossing pattern iscalled honeycomb

pattern. It is seen in

such diseases as

eosinophilic

granuloma of the lung

and bronchiectasis.

Bronchiectasis


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Another diffuse

infiltrative patternIn the lung is

ground-glass

opacification, seen

on CT. Though

non-specific, it is

differentiated from

airspace disease

in that air

bronchograms are

not present and

the blood vesselsare usually still

visible through the

disease.Alveolar proteinosis


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Take Home Points

Though somewhat artificial, lung

disease can be divided into airspace and

interstitial (infiltrative) patterns

Airspace dz is fluffy, confluent with air

bronchograms

Interstitial dz is diffuse, discrete, tends

to occur in lines, dots or a combination

of the two


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Which of the following is

airspace disease or

interstitial lung disease?

Click to go forward

Click to go back


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Airspace or interstitial?

Go ahead


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Go ahead



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Go ahead



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Go ahead



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Correct

This is interstitial disease

There are multiple

discrete nodules in

both lungs. They arewell-defined, do not

have air bronchograms

and do not respect

lobar boundaries.

These are metastases

from a colon cancer.

Go ahead


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Correct

This is airspace disease

There is diffuse

airspace (alveolar)

disease which hassomewhat of a bat-

wing appearance.

The disease is fluffy,

confluent and is not

made up of discretelines or dots. This is

CHF.

Go ahead


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Correct

There is interstitial disease

There are multiple

nodules in both lungs

from metastaticdisease of breast

primary. The disease

occurs in a discrete

nodular pattern with no

air bronchograms.

Go ahead


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Wrong

Look Again

Remember airspace diseases are

fluffy, indistinctly marginated and mayhave air bronchograms

Interstitial lung disease tends to be

discrete nodules or reticular densities,diffuse and inhomogeneous

Go Back


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Congratulations, You Graduate

I know anI know anairspaceairspace

diseasedisease

when Iwhen I

see onesee one

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