3. INDEX
• References
• Introduction
• History Of CT Scan
• Types Of CT Scan
• General Principles
• Planes Of CT Scan
• Lymph-node Stations
• Pattern In Ct Scan
• Special Signs In Ct Scan
4. REFERENCES
• Computed Tomography Of The Lung By Jhony
And Walter- 2nd Edition
• High-resolution Ct Of The Lung Fifth Edition
• Computed Tomography Of The Chest: I. Basic
Principles.
13. CHEST CT : GENERAL PRINCIPLES
• Scan levels : Lung apices to posterior
costophrenic angles.
• Patients position : Supine.
• Lung volume : Full inspiration ,single breath
hold.
• Gantry rotation time : Approximately 0.5s in
most instances.
• Scan duration : Approximately 2.5s for the
thorax using MDCT and fast scanning.
43. THE SECONDARY PULMONARY LOBULES HAS
THREE PRINCIPAL COMPONENTS :
1. The Interlobular Septa.
2. The Centrilobular Region.
3. The Lobular Lung Parenchyma.
44.
45.
46. INTERPRETATION OF CT
SCAN
The three pillars on which the diagnosis of lung
disease on a chest CT is based:
1. The Appearance Pattern,
2. The Location And Distribution Pattern Of The
Abnormalities:
3. Patient Data
47.
48. APPEARANCE PATTERN OF DISEASE
• Abnormalities associated with an increase in
lung density, i.e. increased lung attenuation
• Abnormalities associated with a decrease in
lung density, i.e. decreased lung attenuation
• Abnormalities presenting as nodular opacities
• Abnormalities presenting as linear opacities
50. NODULAR PATTERN
A nodule with a diameter less than 1 cm (small nodule),
larger than 1 cm (large nodule). The term
“micronodule” smaller than 3 mm in diameter. The
term “miliary pattern” indicates the presence of
multiple small (1–3 mm) micronodules with sharp
contours distributed in a major part of the lungs
58. • Increased Lung Attenuation Is Called As
Ground Glass Opacity - If There Is A Hazy
Increase In Lung Opacity Without Obscuration
Of Underlying Vessels
• Consolidation If The Increase In Lung Opacity
Obscures The Vessels
• In Both Ground Glass And Consolidation The
Increase In Lung Density Is The Replacement
Of Air In The Alveoli By Fluid, cells or Fibrosis.
59.
60. • Ground Glass Opacity:-density Of
Intrabronchial Air Appears Darker As The Air In
The Surrounding Alveoli(called As Dark
Bronchus Sign)
• Consolidation:-exclusively Air Left In
Intrabronchial Called As Air Bronchus Sign
61.
62.
63. DECREASED ATTENUATION
PATTERN
Generally four causes of decreased lung
attenuation can be found:
• Hypoperfusion
• Air trapping
• Cystic and cyst-like lesions
• Pulmonary emphysema
64.
65.
66. • Cysts are low-density thin-walled areas that
are well defined and circumscribed and that
have a cellular wall (usually less than 3 mm
thick)
• Most frequent causes of cystic lung changes is
advanced to fibrosis giving rise to
honeycombing or honeycomb cysts
67.
68.
69.
70. RETICULAR/LINEAR PATTERN:-
• TOO MANY LINES EITHER AS ARESULT OF
THICKENING OF LUNG INTERLOBULAR SEPTA
OR INTRALOBULAR SEPTA.
• THICKENING OF LUNG INTERSTITIUM BY FLUID
,FIBROUS TISSUE OR INFILTRATION BY CELLS
RESULTS IN PATTERN OF RETICULAR OPACITY
DUE TO THICKENING OF SEPTA.
•
71. Linear opacities can develop:
• When the interstitium is thickened
• When lymphatics are involved
• When peripheral acinar alveoli are
filled or collapsed
• When blood vessels and airways are
involved
72.
73.
74.
75. CHEST CT SIGNS IN PULMONARY
DISEASE
• The chest CT signs can be broadly categorized
into four groups based on anatomical
distribution: parenchymal, airway, vascular,
and pleural-based signs.
85. CRAZY-PAVING PATTERN
• Superposition of a linear pattern on ground-
glass opacity results in a pattern that is
termed crazy paving.
• This pattern was initially described in patients
with pulmonary alveolar proteinosis.
