TB, Lung Abscess, and Cystic
Fibrosis
TB
• Radiographic findings in primary TB are
Nonspecific
• Tends to like the lower lung zones
• Cavitation is not as common in primary TB
as in reactivation TB
• However lymphadenopathy is a common
finding in primary TB and uncommon in
reactivation TB
TB
• Patchy left lower lobe
opacity
• Looks like pneumonia
TB
• Right upper and lower
lobe consolidation
• Right pleural effusion
TB
• Cavitary right upper
lobe lesion
• Right paratracheal
lymphadenopathy
• Right middle lobe
infiltrate
• Notice the ipsilateral
lymphadenopathy
TB
• Thick walled cavity
with satellite nodules
• Smooth inner wall
TB
• Focal right middle
lobe infiltrate
• Nodular like infiltrate
• Endobronchial spread
of TB
• Adjacent areas of lung
are infected by
bronchial secretions
TB
• Radiographic findings
usually present 2 years
after initial infection
• Infiltrates usually like
the apical and
posterior segments of
upper lobes and
superior segment of
lower lobes
TB
• CT scan through the
upper chest shows a
thick walled cavity
with an air fluid level
and surrounding
infiltrate
• Cavities result from
caseous necrosis
TB
• Complications of TB
cavities
• Mycetoma “fungus
ball”
• Rasmussen Aneurysm
which is weakening of
bronchial artery
adjacent to a cavitary
lesion
Rasmussen Aneurysm
TB
• Bilateral lung nodules
resulting from
endobronchial spread
of TB
• Right upper lobe
cavity
Miliary TB
• Right paratracheal
lymphadenopathy
• Bilateral tiny uniform
nodules
• Diffuse pattern of
nodules is due to
hematogenous spread
Miliary TB
TB Key Points
• Imaging findings of primary TB are
nonspecific
• Primary TB differentiated from bacterial
pneumonia by the presence of
lymphadenopathy
• Reactivation TB recognized by
fibrocavitary disease and a history of prior
exposure
TB Key Points
• Inactive disease cannot be established
without prior films
• Primary TB tends to affect the lower lung
zones while reactivation TB tends to affect
the upper lung zones
Pneumococcal PNA
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Complications
Lung necrosis
Abscess formation
Often need clinical
history to distinguish
from TB
Lung Abscess
• Air fluid level within a
large cavity
• Can communicate
with the pleura
resulting in an
empyema
Lung Abscess
Lung Abscess
• 54 year old male with
cough and foul
smelling sputum
• Cavity within the
superior segment of
the left lower lobe
• Common site for
aspiration
Lung Abscess
• Irregular cavity
• Typically more
posterior
• Often has an air/fluid
level within it
• Often has surrounding
infiltrate
Lung Abscess
• Cavity with air fluid
level and foul smelling
sputum
• Anaerobic organisms
often the cause of
abscesses from
aspiration
Lung Abscess Key Points
• Typical radiographic appearance is an
irregular cavity with an air fluid level
• Lung abscesses from aspiration often occur
in the posterior segments of upper lobes or
superior segments of lower lobes
• The wall thickness of lung abscesses
progresses from thick to thin and irregular
to well circumscribed
Cystic Fibrosis
• Abnormal sodium/chloride transport in
exocrine tissues
• Results in thick viscous mucus
• Obstructs airways resulting in repeat
infections and colonization
• Airways dilate and cysts form from air
trapping
• Scarring from the repeated infections
Cystic Fibrosis
• Hyperinflation
• Upper lobe
bronchiectasis
• Tram tracking