1. The document discusses the common radiological features of various types of pneumonia. It outlines the typical features seen for different bacterial, viral and fungal causes on x-ray including abnormalities in lung opacities, markings and silhouette signs. 2. Examples of specific pathogens are given with details on their usual presentation and affected age groups. Staphylococcus aureus commonly causes multifocal bilateral pneumonia in infants. Klebsiella pneumoniae typically leads to upper lobe consolidation in elderly patients. 3. Other conditions discussed include tuberculosis, nontuberculous mycobacterial infections, Pneumocystis jirovecii pneumonia, fungal infections and bronchiectasis. Images are provided to illustrate

1. Radiological features of pneumonia
Dr. Prithwiraj Maiti
MBBS
House Physician, Department of Internal Medicine
R.G.Kar Medical College
Admin and Founder, Pgblaster India
Author of: “A Practical Handbook of Pathology Specimens and Slides” and “An
Ultimate Guide to Community Medicine”; published by Jaypee Brothers, India

2. Topics to be discussed:
 Radiological anatomy of lung
 Common radiological features of pneumonia
1. Staphylococcus aureus
2. Klebsiella pneumoniae
3. Mycoplasma pneumoniae
4. Pneumocystis carinii
5. Mycobacterium tuberculosis
6. Mycobacterium avium complex
7. Hydatid disease of lung
8. Allergic bronchopulmonary aspergillosis
9. Candida albicans
10. Bronchiectasis

3. Radiological anatomy of right lung
2 fissures, 3 lobes

4. Radiological anatomy of left lung
1 fissure, 2 lobes

5. Common radiological features of pneumonia
1. Abnormal lung opacity
2. Increase in the size and number of lung markings
3. Silhouette signs: Loss of clarity of the diaphragm and heart borders
4. Air bronchogram lines
5. Spine sign: Loss of the normal darkening inferiorly of the thoracic
vertebral bodies on the lateral view (suggesting lower lobe infection)
6. Opacification of the lung behind the heart shadow or below the
diaphragms.

6. Common radiological features of pneumonia
1. There is a dense opacity within
the right upper lobe of the
lung (arrowed)
2. There are also air-
bronchogram lines
3. There is increase in the
number of bronchovascular
markings
4. There is some loss of definition
of the upper right heart border
(silhouette sign).

7. There is abnormal opacity behind the left
heart shadow (arrowed). There are air
bronchogram lines.
Spine sign: This image shows the vertebral
bodies become lighter as we move down
(arrowed). This is caused by consolidation
within the lower lobe.

8. Staphylococcus aureus
• Age group: Infants/ children
• Characteristic pneumatoceles (thin
walled cavities resulting from
localized pulmonary destruction)
• Bronchopneumonia
• Multifocal and bilateral
• Air bronchogram unusual
• Lobar involvement unusual
• In acute phase, it may cause
cavitating pneumonia with pleural
effusion
• May cause hydrothorax/
hydropneumothorax.

9. Klebsiella pneumoniae
• Age group: Elderly patient
• Upper lobe consolidation
• Bulging fissure sign/ Bow
fissure sign.

10. Mycoplasma pneumoniae
• Age group: 20-40 years
• Initial stage: Unilateral lower
lobe involvement beginning at
hilum, fanning out to periphery
• Late stage: Segmental,
peribronchial involvement ->
Lobar involvement.

11. Pneumocystis carinii
• Age group: Children as well as
adults
• Bilateral, symmetrical, diffuse,
fine to medium reticular
opacities
• Sometimes solitary/ multiple
miliary nodules/ thick walled
nodules/ thin walled
pneumatoceles are seen.

12. Mycobacterium tuberculosis: Primary TB
• Ghon’s complex: Tuberculoma
(caseating granuloma) near
interlobar fissure + hilar lymph
node enlargement
• Ranke’s complex: When a
Ghon's complex undergoes
fibrosis and calcification with
calcified draining lymphatics, it is
called a Ranke complex.
• Pleural/ pericardial involvement
• Miliary/ extrapulmonary TB.
Ranke’s complex Miliary TB

13. Mycobacterium tuberculosis: Secondary TB
• Acinar consolidation
• Cavitation
• Endobronchial spread
• Miliary pattern.
Arrow: Cavity, M: Miliary pattern

14. Mycobacterium avium complex (MAC)
• Nodules
• Infiltration (patchy consolidation)
• Cavity
• Ectasia.
[Mnemonic: NICE, 1 or more may
be present]

15. Hydatid disease of lung
• Lung is the most common site of
secondary involvement in
children
• Predominantly lower lobe
involvement
• Calcification of cyst wall rare
• Rib/ vertebral erosion may occur.

16. Signs in hydatid disease of lung
Sign Cause Radiological representation
Meniscus/ Double
arch/ Crescent/
Moon sign
Due to thin crescent of air in
the uppermost of the cyst
Onion peel/ Cumbo
sign
Due to air fluid level inside
endocyst
Serpent sign Collapsed membranes inside
the cyst outlined by air
Water Lilly sign Completely collapsed cyst
floating on the cyst fluid
Cavity All contents of cyst breaks out
via communicating bronchus

17. Allergic bronchopulmonary aspergillosis
• Air crescent/ Monad’s sign:
Characteristic of aspergilloma ->
Fungal ball with air crescent
surrounding it.

18. Allergic bronchopulmonary aspergillosis
• Halo sign: Due to bleed in
invasive aspergillosis.

19. Candida albicans
• Rarely occurs in severely
immuno-compromised patients
with leukemia/ lymphoma/ HIV
patients
• Widespread bilateral interstitial
fluffy alveolar infiltrates;
sometimes progressing to lobar
consolidation.

20. Bronchiectasis
CXR:
• Dilated bronchi
• Tram track appearance
HRCT:
• Honeycombing

21. Thank you….
Resources used: Radiology textbooks and Internet images.