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
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.
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
