1) The document provides guidance on interpreting chest x-rays by focusing on patterns of lung abnormalities including consolidation, pulmonary nodules and masses, and cavitary lesions. 2) Consolidation is described according to its contents, pattern of distribution, and chronicity which helps limit differential diagnoses. Common causes of lobar and diffuse consolidation are also outlined. 3) Pulmonary nodules and masses are differentiated and important characteristics for assessing each such as edges, number, density, and vascular pedicles are highlighted. 4) Cavitary lesions are described based on internal contents and location to suggest potential etiologies such as abscess, ruptured cyst, or pneumatocele.

1. Basic approach to chest X-ray
interpretation
Lecture 6
Dr. Kosar kamal ahmed
HD diagnostic radiology

2. Courtesy of :
• Prof. Dr. mamdouh mahfouz
• Radiology assistant ( chest radiology basic interpretation , chest
radiology lung diseases )

3. Let’s go back to where we skipped
• Technical adequacy
• Cardiothoracic ratio + CP angles
• Mediastinal contour and para vertebral lines
• Lung zones
• Hidden areas
• Bony stuctures

4. Azygo-esophageal line

5. Rt. Paratracheal stripe

6. Let’s go back to where we skipped
• Technical adequacy
• Cardiothoracic ratio + CP angles
• Mediastinal contour and para
vertebral lines
• Lung zones
• Hidden areas
• Bony stuctures

7. Lung zones
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8. Lung zones
try to pic pathology

9. Pattern approach
On a chest x-ray :
• lung abnormalities will either present as areas of
– increased density or as areas of decreased density.
• Lung abnormalities with an increased density also called opacities are the
most common.
• A practical approach is to divide these into four patterns:
– 1. Consolidation ( + opacity of without air bronchogram )
– 2. Interstitial infiltration
– 3. Nodules or masses
– 4. cavitary lesion

10. Important points to keep in mind
• You have to realize that it is not always possible to divide lung abnormalities
into one of these four patterns .
• Sometimes you are confronted with an abnormality that looks like a mass, but
it could also be a consolidation.
– Just do the workup of both the differential diagnosis of masses and consolidation.
– In such a case information from clinical data, old films or follow up films and CT scan will usually
solve the problem.
• Finally in some cases only biopsy will provide a diagnosis .

11. Consolidations
• They can be small or large
• Focal or multifocal
• Central or peripheral
According to the pathogenesis

13. Consolidation
• Consolidation is the result of
replacement of air in the alveoli by
transudate, pus, blood, cells or other
substances.
• Pneumonia is by far the most
common cause of consolidation.
• The disease usually starts within the
alveoli and spreads from one alveolus
to another.
• When it reaches a fissure the spread
stops there .

14. Consolidation
• The keyfindings on the X ray
are :
1. ill defined , homogeneous
opacity obscuring vessels
2. Silhouette sign: loss of lung/soft
tissue interface
3. Air bronchogram
4. Extension to the pleura or
fissure, but not crossing it
5. No volume loss .

15. Consolidation
We may think of consolidation according to it’s
contents

16. Consolidation
Or We may think of consolidation according to pattern of distribution

17. Consolidation
An other way to approach consolidation is by
chronicity

18. Consolidation
• It is very important to differentiate between acute consolidation and chronic
consolidation, because it will limit the differential diagnosis.
In chronic consolidation we think of :
i. Neoplasm with lobar or segmental post-obstructive pneumonia.
ii. Lung neoplasms like bronchoalveolar carcinoma and lymphoma.
iii. Chronic post-infection diseases like organizing pneumonia (OP) or chronic
eosinophilic pneumonia, which both present with multiple peripheral
consolidations.
iv. Sarcoidosis is the great mimicker and sometimes the granulomatous noduli
are so small and diffuse that they can present as consolidation ,This is
known as alveolar sarcoidosis .
v. Alveolar proteinosis is a rare chronic disease that is characterized by filling
of the alveoli with proteinaceous material.

19. Consolidation
• The most common presentation of consolidation is lobar or segmental.
The most common diagnosis is lobar pneumonia.

20. Lobar consolidation
• increased density with ill defined borders in the left lung
• the heart silhouette is still visible, which means that the density is in the
lower lobe
• Air bronchogram

21. Lobar consolidation
• In consolidation there should be
no or only minimal volume loss,
which differentiates consolidation
from atelectasis.
• Expansion of a consolidated lobe
is not so common and is seen in
Klebsiella pneumoniae and
sometimes in Streptococcus
pneumoniae, TB and lung cancer
with obstructive pneumonia.

22. Lobar consolidation
• Based on the images alone, it is usually not possible to determine the cause of the consolidation.
• Other things need to be considered, like acute or chronic illness, clinical data and other non pulmonary
findings.
• Here we have a number of xrays with consolidation ; Notice the similarity between these chest x rays
Lobar pneumonia in a patient with cough and feverPulmonary hemorrhage in a patient with hemorrhageOrganizing pneumonia (OP) multiple chronic consolidations
Infarction : peripheral consolidation in a patient with acute
shortness of breath with low oxygen level and high D-dimer

23. Lobar consolidation
• Based on the images alone, it is usually not possible to determine the cause of the consolidation.
• Other things need to be considered, like acute or chronic illness, clinical data and other non pulmonary
findings.
• Here we have a number of xrays with consolidation ; Notice the similarity between these chest x rays
Pumonary cardiogenic edema filling of the alveoli with transudate in a
patient with congestive heart failure.
Sarcoidosis : at first glance this looks like consolidation, but in fact this is
nodular interstitial lung disease, that is so widespread that it looks like
consolidation .

24. Diffuse consolidation
• The most common cause of diffuse consolidation is pulmonary edema due to heart
failure.

25. Diffuse consolidation
• bilateral perihilar consolidation with air bronchograms and ill defined borders
• an increased heart size
• subtle interstitial markings
• probably a large vascular pedicle.

26. Diffuse consolidation
• Unlike lobar pneumonia, which starts in the alveoli, bronchopneumonia starts in the airways as acute
bronchitis.
• It will lead to multifocal ill defined densities.
• When it progresses it can produce diffuse consolidation.
• The disease does not cross the fissures, but usually starts in multiple segments.
• Bronchopneumonia can be caused by many microorganisms.
• This proved to be legionella pneumonia

27. Diffuse consolidation
• The chest x ray shows diffuse consolidation with 'white out' of the left lung with an airbronchogram.
• This patient had a chronic disease with progressive consolidation.
• The disease started as a persitent consolidation in the left lung and finally spread to the right lung.

28. An other approach is to notice pattern of
distribution

29. • A bilateral perihilar distribution of
consolidation is also called a
Batwing distribution.
• The sparing of the periphery of the
lung is attributed to a better
lymphatic drainage in this area.
• It is most typical of pulmonary
edema, both cardiogenic and
noncardiogenic.
• Sometimes it is seen in
pneumonias
• Peripheral or subpleural
consolidation is called reverse
Batwing distribution.
• It is frequently seen in chronic
lung disease .

30. • Multifocal consolidations are also described as
multifocal ill defined opacities or densities.
• In most cases these are the result of airspace
consolidations due to bronchopneumonia.
• Bronchopneumonia starts in the bronchi and then
spreads into the lung parenchyma.
• This can lead to segmental, diffuse or multifocal ill
defined densities.
• In some cases however the underlying pathology of
multiple ill defined densities is interstitial disease , like
in the alveolar form of sarcoidosis in which the
granulomas are very small and fill up the alveoli .

31. This patient had a several month history of chronic nonproductive
cough, that did not respond to antibiotics
• Probably we are dealing with multifocal consolidations
• but one might also consider the possibility of multiple ill defined masses
• Biopsy revealed the diagnosis of organizing pneumonia (OP)

32. Summary :
acute focal consolidation can be
pneumonia or infarction
Pneumonia Infarction

33. Pulmonary nodules and masses
• A well defined opacity that is < 3 cm on a CXR is a nodule
• A well defined opacity that is > 3 cm in a CXR is a mass

34. Pulmonary nodules
DDx

35. Pulmonary nodules

36. Pulmonary nodule
how to assess ?
Well defined edge Vs.
spiculated edge

37. Pulmonary nodule
how to asses ?
• Number : multiple nodules are usually metastatic or less likely H. cysts
• A well defined edge is usually on the benign while spiculated edge is
malignant
• Presence of calcification or especially pop corn calcification is benign .
• Density : usually assessed by CT
– Fat --- pathognomonic for hamartoma
– Fluid --- H. cyst
– Soft tissue --- metastasis or primary carcinoma
• Vascular pedicle ---- AVM

38. Some nodules can be indeterminate and need
CT or FNA for further evaluation

39. Pulmonary masses

40. Pulmonary masses
• Any pulmonary mass in an adult is carcinoma until proved otherwise
• Presence of calcification is benign in nodule while not in mass
• Multiplicity of the masses can be metastases or multiple hydatids

41. How to differentiate multiple pulmonary masses
from multiple pulmonary metastases ?
• There are three signs that make
the diagnosis of H. possible by
CXR :
1. Extreme sharp margin
2. Air in the wall ( halo sign )
3. Air / fluid level ( water lilly
sign )

42. Cavitary lesions
• A cavity is defined as a ‘gas-filled space,
seen as a lucency or low attenuation area .
• The cavity is usually the result of the
expulsion or drainage of a necrotic part of
the lesion via the bronchial tree.
• Although air–fluid levels may be seen in
cavitations, the term is not synonymous with
abscess .

43. Cavitary lesions

44. Cavitary lesions
• Thick walled cavity
• Containing air alone
• Internal surface of the cavity
– Smooth – chronic abscess
– Irregular – malignant ( cavitating :
primary /secondary mass )

45. Cavitary lesions
• Thick walled cavity
• Containing air / fluid level
• Look for the surface of the fluid
level :
– Regular ( linear ) – chronic
abscess
– Irregular ( undulating ) – ruptured
hydatid cyst

46. Cavitary lesions
abscess

47. Cavitary lesions
hyatid cyst
• Only three signs are
dependable in CT to diagnose
H. cyst :
– Floating shadows within the
cyst
– Calcification in the wall
– Daughter cysts

48. Cavitary lesions
• Thick walled cavity
• Containing air + mass
• They can be :
– Fungal ball ( mycetoma )
– Ruptured hydatid
– Necrotic tumor
– Blood clot

49. Cavitary lesions
• Thin walled cavity
• Containing air
• Look for the location of the
cavity :
– Central ( in lung parenchyma ) –
pneumatocele
– Peripheral ( sub-pleural) –
emphysematous bulla

50. Cavitary lesions