1. HOW READ CHEST CT -2
ANAS SAHLE ,MD

2. Basic elements
Appearance
pattern
Distribution
Patient data
pattern
Ct
interpretation

3. Normal HRCT Findings
airways
Normal airways are visible only to
within 3 cm of the pleura.
The centrilobular bronchiole, with a diameter of 1
mm and a wall thickness of 0.15 mm, is not
normally visible on HRCT.

4. Normal HRCT Findings
small pulmonary arteries and veins
More peripherally, numerous small "dots" and a few
branching lines represent small pulmonary arteries
and veins. Throughout, arteries branch at acute
angles, and veins branch at 90° angles
Centrilobular arteries (1 mm in
diameter) are V- or Y-shaped
structures on HRCT seen within 5 to
10 mm of the pleural surface.
Pulmonary veins (0.5 cm) are occasionally seen as
linear or dotlike structures within 1 to 2 cm of the
pleura and, when visible, indicate the locations of
interlobular septa

5. FIGURE 17.3. HRCT Findings in
Interstitial Lung Disease
1- Interlobular (Septal) Lines
2-Intralobular Lines
3-Thickened Fissures
4-Thickened bronchovascular
structures Dot lik
5-Centrilobular (Lobular tree-in-bud
Core) Abnormalities lldefined
6- Subpleural lines
7-Parenchymal bands
8-Honeycombing
9-Thin-walled cysts
10-Irregularity of Lung Interfaces
11-Ground-Glass or Hazy
Increased Density
12-Architectural Distortion and
Traction Bronchiectasis
13-Conglomerate Masses
14-Consolidation

6. Appearance pattern
Increased Decreased
Nodular Linear
lung lung
opacities opacities
attenuation attenuation

7. Increased lung attenuation
Ground-glass opacity
Consolidation

8. Ground-glass opacity(GGO)
• GGO:
• hazy increase in lung density,
• with preservation of airway vessel margins.
• The density of the intra-bronchial air appears
darker as the air in the surrounding alveoli.
This is called the 'dark bronchus' sign
• Occurs when:
• there is mild decrease in the amount of air in air-
spaces(Air space disease )
• when there is mild increase in size andor
amount of soft tissue structures (Interstitial lung disease ).
• two phenomena that often occur simultaneously.

9. High Attenuation pattern
1. Ground-glass-
opacity (GGO)
2. Consolidation
High Attenuation

13. WHAT IS DOMINANT PATTERN ?

14. Ground-glass opacity
Treatable or not treatable?

15. Ground-glass opacity
Treatable or not treatable ?
Acute / 1. Reticular Pattern
60-80%
Active Treatable 2. Ground-glass
of cases
pathology opacity
1. Taction
20-40% Chronic not Bronchiectasis
of cases pathology treatable 2. Honeycombing
3. Cysts

16. Ground-glass opacity
Treatable or not treatable ?
Acute / 1. Reticular Pattern
60-80% Potentially
Active
of cases treatable 2. Ground-glass
pathology opacity
1. Taction
20-40% Chronic not Bronchiectasis
of cases pathology treatable 2. Honeycombing
3. Cysts

17. Ground-glass opacity
Treatable or not treatable ?
Acute / 1. Reticular Pattern
60-80% Potentially
Active
of cases treatable 2. Ground-glass
pathology opacity
1. Taction
20-40% Chronic not Bronchiectasis
of cases pathology treatable 2. Honeycombing
3. Cysts

18. Ground-glass opacity
Treatable or not treatable ?
Acute / 1. Reticular Pattern
60-80% Potentially
Active
of cases treatable 2. Ground-glass
pathology opacity
1. Taction
20-40% Chronic not Bronchiectasis
of cases pathology treatable 2. Honeycombing
3. Cysts

19. Ground-glass opacity
Treatable or not treatable ?
Acute / 1. Reticular Pattern
60-80% Potentially
Active
of cases treatable 2. Ground-glass
pathology opacity
1. Taction
20-40% Chronic Not Bronchiectasis
of cases pathology treatable 2. Honeycombing
3. Cysts

20. Ground-glass opacity
Treatable or not treatable ?
Acute / 1. Reticular Pattern
60-80% Potentially
Active
of cases treatable 2. Ground-glass
pathology opacity
1. Taction
20-40% Chronic Not Bronchiectasis
of cases pathology treatable 2. Honeycombing
3. Cysts

21. Ground-glass opacity
Treatable or not treatable?
• Potentially treatable
lung disease

22. Ground-glass opacity
Treatable or not treatable?
• Radiological Findings
of fibrosis:
• Traction
bronchiectasis
• Honeycombing

23. Ground-glass opacity
Treatable or not treatable?
• Traction Bronchiectasis
• Honeycombing
Non specific interstitial pneumonitis (NSIP)

24. Crazy Paving

25. Crazy Paving in a patient with Alveolar
proteinosis
Linear Crazy-
GGO
pattern paving
• Crazy Paving is a combination of ground glass opacity
with superimposed septal thickening

26. Consolidation
• Defined as:
• Increased in lung density
• with obscuration of underlying vessels
and airway walls,
– an air-bronchogram may be present.
• Air-space nodules, focal area of GGO are often
seen in association with consolidation.

27. Increased lung attenuation
Preservation of B-V Obscuration of vascular
marking=GGO marking=consolidation
Symptoms course Symptoms course
(acute,sub-acute,chronic) (acute,sub-acute,chronic)
Centri-lobular
Linear pattern sub-pleural Other pattern
No linear pattern
superimposed patchy diffuse also
lobar
Centri-lobular
DD for other
CRAZY PAVING Sub-pleural pattern
Patchy,diffuse

28. Increased lung attenuation
Appearance pattern
GGO Cosolidation
Patient data(symptoms course)
Acute Sub-acute Chronic
Distribution patternother pattern
Centri-lobular Sub-pleural Patchy Diffuse Lobar
Regional lung distribution
Upper lowerdiffuse Central peripheral

29. Acute
GGOconsolidationcrazy-paving
Pulmonary infection
Pulmonary edema
Pulmonary hemorrhage
ARDS
Acute intrstitial pneumonia
Eosinophilic pnrumonia
Radiation pneumonia

30. Sub-acutechronic course
GGO
Hyper-sensitivity pneumonitis
Smoking related paranchymal disease
UIPIPF
NSIP
Lymphocytic interstitial pneumoniaLIP
Alveolar proteinosis
Asbestosis
Vasculitis(churg-strauss syn)
Eosinophylic pneumonia(chronic)
COP
Bronchoalveolar CA
Lipoid pneumonia
Sarcoidosis

31. Sub-acutechronic course
cosolidation
COP
Bronchoalveloar CA
UIPIPF
NSIP
Lymphocytic interstitial pneumoniaLIP
Lymphoma
Vasculitis(churg-strauss syn)
Eosinophylic pneumonia(chronic)
Hyper-sensitivity pneumonitis
Lipoid pneumonia
Sarcoidosis

32. Sub-acutechronic course
crazy-paving
UIPIPF
NSIP
Lymphangitic spread of tumor
Alveolar proteinosis
Vasculitis(churg-strauss syn)
Eosinophylic pneumonia(chronic)
COP
Bronchoalveolar CA
Lipoid pneumonia
Sarcoidosis

33. Centri-lobular nodular
GGO
Hyper-sensitivity pneumonitis
Organizing pneumonia
Pulmonary infection
Pulmonary edema
Pulmonary hemorrhage
vasculitis
Metastatic calcification
Lymphocytic interstitial pneumonia(sjogren,AIDS)

34. Centri-lobular nodular
consolidation
• Hyper-sensitivity pneumonitis
• Organizing pneumonia
• Pulmonary infection
• Pulmonary edema
• Pulmonary hemorrhage
• Bronchoalveolar carcinoma
• Aspiration
• vasculitis
• Lymphocytic interstitial pneumonia(sjogren,AIDS)

35. Sub-pleural
GGO
UIPIPF
Organizing pneumonia
Eosinophylic pneumonia
Asbestosis

36. Sub-pleural
consolidation
• Eosinophylic pneumonia
• Organizing pneumonia
• UIPIPF

37. Patchy
GGO
Hyper-sensitivity pneumonitis
NSIP
DIP
Alveolar proteinosis
Pulmonary hemorrhage
vasculitis
Sarcoidosis

38. Patchy
consolidation
• Hyper-sensitivity pneumonitis
• NSIP
• DIP
• Pulmonary hemorrhage
• vasculitis
• Sarcoidosis

39. Diffuse
GGO
Hyper-sensitivity pneumonitis
Smoking related lung diseases
Pulmonary infection
Pulmonary edema
Pulmonary hemorrhage
Alveolar proteinosis
Acute interstitial pneumonia(AIP)
ARDS
NSIP

40. Diffuse
consolidation
• Hyper-sensitivity pneumonitis
• Pulmonary infection
• Pulmonary edema
• Pulmonary hemorrhage
• Alveolar proteinosis
• AIP
• ARDS
• NSIP

41. Lobar
consolidation
• Pulmonary infection
• Bronchoalveolar carcinoma
• Organising pneumonia
• Lymphoma

42. Regional distribution
Upperlowerdiffuse Centralperipherial Posterioranterior
zone zone zone

43. Regional distribution
Upper zone Lower zone diffuse zone
• Sarcoidosis • oedema • Hyper-sensetivity
• Tuberculosis • UIP pneumonitis
• Chronic • NSIP • Diffuse
eosinophylic • DIP pneumonia
pneumonia. • COP • Lymphangitic
• Lipoid pneumonia spread of tumor
• Alveolar • Sarcoidosis
hemorrhage

44. Regional distribution
Central zone Peripheral zone
• Sarcoidosis • Asbestosis
• Lymphagitic spread of tumor • UIP
• Alveolar proteinosis. • NSIP
• DIP
• COP
• Chronic eosinophylic pneumonia
• Hyper-sensitivity pneumonitis.
• Acute interstitial pneumonia.
• Septic emboli
• Pulmonary embolisem.

45. Regional distribution
Posterior
• oedema
• ARDS
• UIP
• NSIP
• Asbestosis
• Sarcoidosis
• Hyper-sensitivity pneumonitis
• Lipoid pneumonia

46. High Attenuation