13. Extra Pleural Sign
Cancer Lung
Density in periphery
Sharp inner margin
Indistinct outer margin
Angle of contact with chest wall
Expanding destructive rib lesion
Paratracheal widening
This is an example of an RUL lesion
17. Lateral Chest
There is valuable information that can be obtained by a chest
lateral view. A few of them are listed below:
Sternum
Vertebral column
Retrosternal space
Localization of lung lesions
Lobes of lungs
Oblique fissures
Pulmonary artery
Heart
Aorta
Mediastinal masses
Diaphragm
Volume measurements
SPN
Radiologic TLC
Tracheoesophageal stripe
18. Tuberculosis of Spine
Loss of intervertebral space
Vertebral collapse
Cold abscess is not present in this case. PA view is not diagnostic.
20. RML Atelectasis
Vague density in right lower lung field, almost normal
RML atelectasis in lateral view, not evident in PA view
21. Atelectasis Left Upper
Lobe
Hazy density over left
upper lung field
Loss of left heart
silhouette
Tracheal shift to left
A: Forward movement of oblique
fissure
C: Atelectatic LUL
B: Herniated right lung
22. Localization
When a lesion is not contiguous to a
silhouette, it is not possible to localize it
without a lateral view. This is a case of a
solitary pulmonary nodule with popcorn
calcification: Hamartoma.
23.
24.
25.
26.
27. Air Bronchogram
• In a normal chest x-ray, the tracheobronchial tree is not
visible beyond the 4th order. As the bronchial tree
branches, the cartilaginous rings become thinner, and
eventually disappear in respiratory bronchioles. The
lumen of the bronchus contains air and the surrounding
alveoli contain air. Thus, there is no contrast to visualize
the bronchi.
• The air column in the bronchi beyond the 4th order
becomes recognizable if the surrounding alveoli is filled,
providing a contrast or if the bronchi get thickened
• The term air bronchogram is used for the former state
and signifies alveolar disease.
28.
29. Silhouette Sign
Adjacent Lobe/SegmentSilhouette
RLL/Basal segmentsRight diaphragm
RML/Medial segmentRight heart margin
RUL/Anterior segmentAscending aorta
LUL/Posterior segmentAortic knob
Lingula/Inferior segmentLeft heart margin
LLL/Superior and basal segmentsDescending aorta
LLL/Basal segmentsLeft diaphragm
Cardiac margins are clearly seen because there is contrast between the fluid
density of the heart and the adjacent air filled alveoli. Both being of fluid density,
you cannot visualize the partition of the right and left ventricle because there is no
contrast between them. If the adjacent lung is devoid of air, the clarity of the
silhouette will be lost. The silhouette sign is extremely useful in localizing lung
lesions.
30.
31. Atelectasis Right Lung
Homogenous density right hemithorax
Mediastinal shift to right
Right hemithorax smaller
Right heart and diaphragmatic silhouette are not identifiable
32. Atelectasis Left Lung
Homogenous density left hemithorax
Mediastinal shift to left
Left hemithorax smaller
Diaphragm and heart silhouette are not identifiable
33. Lateral
Movement of oblique and transverse
fissures
Atelectasis Right Upper Lobe
Homogenous density right upper lung
field
Mediastinal shift to right
Loss of silhouette of ascending aorta
34. Atelectasis Left Upper
Lobe
Hazy density over left
upper lung field
Loss of left heart
silhouette
Tracheal shift to left
Lateral
A: Forward movement of
oblique fissure
B: Herniated right lung
C: Atelectatic LUL
35. Consolidation Right
Upper Lobe /
Density in right upper lung
field
Lobar density
Loss of ascending aorta
silhouette
No shift of mediastinum
Transverse fissure not
significantly shifted
Air bronchogram
36. Consolidation Left Lower Lobe
Density in left lower lung field
Left heart silhouette intact
Loss of diaphragmatic silhouette
No shift of mediastinum
Pneumatocele
One diaphragm only visible
Lobar density
Oblique fissure not significantly
shifted
37. Left Upper Lobe Consolidation
Density in the left upper lung field
Loss of silhouette of left heart margin
Density in the projection of LUL in lateral view
Air bronchogram in PA view
No significant loss of lung volume
38. Vague density right lower lung field
Indistinct right cardiac silhouette
Intact diaphragmatic silhouette
Density corresponding to RML
No loss of lung volume
RML pneumonia
39. S Curve of Golden
When there is a mass
adjacent to a fissure, the
fissure takes the shape
of an "S". The proximal
convexity is due to a mass,
and the distal concavity is
due to atelectasis. Note the
shape of the transverse
fissure.
This example represents a
RUL mass with atelectasis
40. Tracheal Shift
Trachea is index of upper mediastinal position. The pleural pressures on either
side determine the position of the mediastinum. The mediastinum will shift
towards the side with relatively higher negative pressure compared to the
opposite side. Tracheal deviation can occur under the following conditions:
• Deviated towards diseased side
– Atelectasis
– Agenesis of lung
– Pneumonectomy
– Pleural fibrosis
• Deviated away from diseased side
– Pneumothorax
– Pleural effusion
– Large mass
• Mediastinal masses
• Tracheal masses
• Kyphoscoliosis
41. Atelectasis Right Lung
• Homogenous density
right hemithorax
• Mediastinal shift to right
• Right hemithorax smaller
• Right heart and
diaphragmatic silhouette
are not identifiable
•
42. Pleural Effusion Massive
• Unilateral homogenous
density
• Mediastinal shift to right
• Left diaphragmatic and
left heart silhouettes lost
• Left hemithorax larger
45. Air Bronchogram
• In a normal chest x-ray, the tracheobronchial tree is not
visible beyond the 4th order. As the bronchial tree
branches, the cartilaginous rings become thinner, and
eventually disappear in respiratory bronchioles. The
lumen of the bronchus contains air and the surrounding
alveoli contain air. Thus, there is no contrast to visualize
the bronchi.
• The air column in the bronchi beyond the 4th order
becomes recognizable if the surrounding alveoli is filled,
providing a contrast or if the bronchi get thickened
• The term air bronchogram is used for the former state
and signifies alveolar disease.
46.
47. Bowing Sign
• In LUL atelectasis or
following resection, as in
this case, the oblique
fissure bows forwards
(lateral view). Bowing
sign refers to this feature.
The arrow points to the
forward movement of the
left oblique fissure.
48. Doubling Time
• Time to double in volume (not diameter)
• Useful in determining the etiology of solitary
pulmonary nodule
• Utility
– Less than 30 days: Inflammatory process
– Greater than 450 days: Benign tumor
– Malignancy falls in between
49. Eccentric Location of Cavity in a
Mass
• Thick wall and irregular lumen can be
seen in both malignancy and
inflammatory lesions.
• However eccentric location of cavity is
diagnostic of malignancy.
50. • This is an example of
squamous cell
carcinoma lung.
• LUL mass
• Thick walled cavity
• Eccentric location of
cavity
• Fluid level
• This is diagnostic of
malignancy.
51. Cortical Distribution
• Mirror image of pulmonary edema
• Alveolar disease of outer portion of lung
• Encountered in:
– Eosinophilic pneumonia
– Bronchiolitis obliterans with pneumonia
52. Medullary Distribution
• It is also called "butterfly pattern"
• Note the sparing of lung periphery both in
the CT, PA and lateral views
• This is one of the radiologic signs
indicative of diffuse alveolar disease
• This is an example of alveolar proteinosis.
53. Note the sparing of lung periphery both in the CT, and PA view
This is one of the radiologic signs indicative of diffuse alveolar disease
This is an example of alveolar proteinosis.
54. Diffuse Alveolar Disease
Radiological Signs
• Butterfly distribution / Medullary distribution
• Lobar or segmental distribution
• Air bronchogram
• Alveologram
• Confluent shadows
• Soft fluffy edges
• Acinar nodules
• Rapid changes
• No significant loss of lung volume
• Ground glass appearance on HRCT
58. Acinar Nodules
InterstitialAcinar
Same size
Sharp edges
smaller
Varying in size
Indistinct edges
Larger than interstitial nodules
Acinar nodules are difficult to distinguish from interstitial
nodules. Some distinguishing characteristics are as follows:
59.
60. Cut Off Sign
• When you see an abrupt ending of visualized
bronchus, it is called a "cut off sign". It indicates
an intrabronchial lesion. This is useful to identify
the etiology of atelectasis . Be careful as the
tracheobronchial tree is three dimensional and
the finding need to be confirmed with tomogram.
In the modern era, a CT scan will take care of
this.
62. Wedge Shaped Density
The wedge's base is pleural
and the apex is towards the
hilum, giving a triangular
shape. You can encounter
either of the following:
Vascular wedges :
Infarct
Invasive aspergillosis
Bronchial wedges :
Consolidation
Atelectasis
63. Polycyclic Margin
The wavy shape of
the mediastinal mass
margin indicates that
it is made up of
multiple masses,
usually lymph nodes.
This is a case of
lymphoma.
64. Open Bronchus Sign / Alveolar Atelectasis
The right lung is atelectatic. You can see air bronchogram, which indicates
that the airways are patent .This case is an example of adhesive alveolar
atelectasis.
65. Pulmonary Artery Overlay
Sign
This is the same concept as
a silhouette sign. If you can
recognize the interlobar
pulmonary artery, it means
that the mass seen is either
in front of or behind it.
This is an example of a
dissecting aneurysm.
66. S Curve of Golden
When there is a mass
adjacent to a fissure, the
fissure takes the shape
of an "S". The proximal
convexity is due to a mass,
and the distal concavity is
due to atelectasis. Note the
shape of the transverse
fissure.
This example represents a
RUL mass with atelectasis
67. Tracheoesophageal Stripe
The posterior wall of the trachea (T)
and the anterior wall of the esophagus
(E) are in close contact and form the
tracheoesophageal stripe in the lateral
view (arrow).
It is considered abnormal when it is
wider than __ mm.
Common causes for thickening of
tracheoesophageal stripe are:
Esophageal disease
Nodal enlargement
