Differentiating theCauses of an OpacifiedHemithorax
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© William Herring, MD, FACR
Three Major Causes + 1
Atelectasis of an entire lung
A large pleural effusion
Pneumonia of an entire lung
And a fourth cause:
Post-pneumonectomy – removal of anentire lung
Atelectasis of the Lung
Atelectasis of an entire lung = loss ofvolume of the affected lung
Visceral and parietal pleura do NOTseparate from each other
There is a shift of heart and hemidiaphragmtoward side of opacification (toward side ofvolume loss)
The righthemithoraxis opaque
There is a shiftof the heart andtrachea towardthe side of theopacification
Atelectasis of the Right Lung
Pleural Effusion
If an effusion (whatever the fluid is) fillsthe entire hemithorax
It acts like a mass
Pushing the heart and trachea away fromthe side of opacification
The righthemithoraxis opaque
There is a shiftof the heart andtrachea awayfrom the side ofopacification
Large Right Pleural Effusion
Pneumonia
The hemithorax is opaque and there isno shift of the heart or trachea
The lefthemithoraxis opaque
There is no shiftof the heart ortrachea
Pneumonia of the LUL
The opacifiedhemithoraxcontains airbronchograms
Post-Pneumonectomy
When the entire lung is removed, there isvolume loss on the pneumonectomizedside
The hemithorax eventually fibroses andbecomes opaque
Clues: There is frequently a resected fifthrib and/or surgical clips
The lefthemithoraxis opaque
There is a shiftof the heart andtrachea towardthat sideindicatingvolume loss
Pneumonectomy on the left
The left 5th ribhas beenresected
Take Home Points
In atelectasis, there is s shift toward theside of the opacification
In pleural effusion, there is a shift awayfrom the side of the opacification
In pneumonia, there is no shift
In pneumonectomy, the 5th rib is usuallyabsent
Congratulations, You Graduate
You know how totell pneumonia,atelectasis andpleural effusionapart
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