•A frequent finding on chest imaging is the presence of fluid

“Fluid” can be simplified into:

Pus

Blood

Water

•“Where” you see that fluid can help define the pathology

•“Diffuse Fluffy Clouds”

Diffuse patchy infiltrates can frequently be seen on imaging

Looks like diffuse fluffy clouds over the lungs

•In general, let your history and exam be your guide

Imaging is meant to help your diagnosis, not necessarily make one

•In general:

Consider a diffuse pulmonary process

Viral pneumonia

CHF

•Viral Pneumonia

•CHF

Pulmonary edema

Fluid increases the density of the lungs

They will appear “fluffier” on imaging, and be diffuse (not confined to just one lobe)

If an x-ray is “hard to read,” (infiltrates make it look too “fuzzy”) consider if there is extra fluid (pulmonary edema) obscuring the lung fields.

•Fluid outside the lungs.

Picture the lungs like sponge

Fluid “in” the lungs is equivalent to a wet sponge (the water stays in the sponge)

Fluid can exist separately around the lungs

This is the pleural effusion

(Fluid between the chest wall and the lung parenchyma)

An effusion can be:

Water

Bile (rare)

Blood (hemothorax; almost always associated with trauma)

Pus (empyema – super sick patients, need procedure to remove this fluid)

Etc.

•When looking for pleural effusions:

Remember that gravity brings fluid down, and air up

Fluid will settle to the dependent part of the patient (usually the base of the lungs)

Look for blunting of the costophrenic angle (dense fluid is “filling in” that space)

•CHF

Heart failure is a “clinical diagnosis” (remember that, you’ll be tested on rounds – seriously); however, certain features on chest imaging can help lead us, or help confirm, the diagnosis.

The heart may be enlarged

Generally the heart will be <50% of the horizontal length of the chest

There may be pulmonary venous congestion

This can be challenging to identify

There may be pulmonary edema

“Wet lungs” (think of the lungs like a sponge)

There may be pleural effusions

Look for blunting of the costophrenic angle

The “Dense Whiteout of a whole Lobe”

•CHF

Pulmonary Edema

Picture the lungs like a sponge.  The heart is a pump, if fluid can’t pump forward, it backs up (this is an over simplification), that fluid parks itself in certain places (the lungs and the legs).  Fluid in the lungs can be seen on imaging.

Some chest x-rays will show clear involvement of a single lung lobe

Frequently associated with pneumonia (PNA)

•COPD

•A good thought process:

Chronic obstructive pulmonary disease

The “lungs” only have one dedicated muscle – the diaphragm

Getting air “into” the lungs, is not hard (muscle supported)

Getting air “out” of the lungs, is more challenging

This is where any kind of “obstruction” limits us

End result:  Air in = easy; Air out = difficult

Consequence:  Lots of air comes in, lung overinflates, now it is difficult to get even more air in

Ultimately:  Limited in getting air in, because there is already too much air

•COPD is ultimately a destructive process

Personally:  Kinda looks like fine cobwebs

We can see this on lung imaging

You may see bullae

This can vary in size and distribution

Note:  CT imaging has multiple windows (lung, liver, bone, etc.)

Lung disease can best be seen on lung windows

•Official Radiology Read:

•Extensive pulmonary emphysema. A few ground glass opacities are seen in the right lower lobe concerning for inflammatory changes, new since recent PET/CT.

•What are ground glass opacities?

These are a finding on CT imaging

The appearance on CT is similar to “ground glass” (like when you scratch the bottom of a glass test-tube – which likely hasn’t been done in decades).

This can relate to multiple pathologies:

Interstitial thickening, inflammation, edema, hemorrhage, fibrosis, etc.

Associated diagnoses include infectious processes, chronic interstitial diseases, acute alveolar diseases, etc.

In General:  Identify this finding as a sign of potentially unhealthy lungs

•Notice the “lighter” areas on CT imaging

•Gastric Bubble

Can be seen on chest and abdominal x-rays

This is a normal finding and a good landmark on CXR’s

•“What’s the deal with the radiologist reading of ‘enlarged heart?’”

Not uncommon finding on radiology reads

Should you be worried?

Double check the order or how the CXR was completed

The standard is:  2-view (front and side), “PA and Lateral PA views”

PA means the x-ray beam went through the back of the patient (posterior) toward the front of the patient (anterior) onto the film (which is what gets read)

The ER frequently does an “AP view” (so the patient doesn’t have to move)

The heart will appear bigger on AP views than PA views

If the x-rays go anterior first, the heart shadow that’s picked up on the film will be bigger than if the x-rays went through the body first, then the heart, and then immediately into the film

Think of making shadow puppets with a flashlight

Moving your fingers toward the light and away from the wall (moving the heart toward the rays and away from the film – the AP view) makes the shadow (the heart) look bigger.

•Pericardial Effusion

Fluid in the pericardial space

Think of the heart in a leather bag.

The heart is always moving (beating), and needs lubrication between the muscle and the bag (the pericardium); otherwise, there is inflammation and complications

There is always a small amount of fluid within the pericardial space (acts as a lubricant)

Certain conditions can cause additional fluid to accumulate

If this happens quickly…

The leathery bag is too stiff/strong and doesn’t expand.  If the volume of the pericardial space doesn’t change, than pressure builds up, pushing on the heart.  Since the right ventricle is lower pressure, right-sided complications may develop (this is tamponade).

Special note:  The left side can pump only what the right side gives it; eventually, the whole heart suffers.

If this happens slowly…

There is time for the leathery bag to expand and accommodate this fluid.  The effusion develops and can become quite large

These bigger effusions can be seen on imaging

•ProTip:

Pericardial Effusions can (sometimes) be identified on EKG

The heart is anchored only by the great vessels

So the heart tissue itself is free to “move”

Generally not an issue because it is contained in the pericardium

If there is a lot of fluid in the pericardial space, the heart has more room to move

The force of the contraction can “swing” the heart around the space

This causes changes in the EKG called “electrical alternans”

Look for EKG spikes that “alternate” in amplitude (big-small-big-small-etc.)

•Pneumothorax

Air between the chest wall and the lung pleura

Can be seen on x-rays

The hint is to look for vessels in the center of view and follow them out to the periphery

If they don’t make it all the way, there might be a pneumothorax

Sometimes you can see a line identifying the edge of the lung tissue

This can still be hard to find

ProTip:  Turn the patient!

Remember that “left lateral decubitus” position?  We can x-ray a patient in this position.

Air always rises, making it form a pocket against the lateral side of the patient (the new “up”)

Far easier to see on CT

Air is black on CT, lung parenchyma (lung tissue) has a density (it will be gray)

Think of the lung like a “sponge” (a mix of air and tissue)