This document summarizes computed tomography findings for various chest diseases. It describes imaging appearances of different types of pneumonia including streptococcus, staphylococcus, haemophilus influenzae, klebsiella and pseudomonas. It also discusses tuberculosis and various lung cancers such as adenocarcinoma, squamous cell carcinoma, small cell carcinoma and lymphoma. Key imaging features for differentiating benign from malignant lung nodules are provided. Imaging patterns for various infectious, inflammatory and neoplastic lung diseases are concisely described.

1. Computed Tomography in
Chest Diseases
Dr. Rikin Hasnani

2. • Developmental Anomalies
• Airway Diseases
• Pneumonias
• Neoplastic diseases
• Diffuse Lung Diseases
• Disease of mediastinum , Pleura & Chest Wall

3. Pneumonia

4. • Streptococcus pnemoniae
• Staphylococcus aureus
• Haemophilus influenza
• Klebsiella
• Pseudomonas
• Legionella
• Tuberculosis

5. Pneumococcal Pneumonia
It is the most common cause of Pneumonia.
• It is more common in male, elderly, during winter or at the end of dry
season, usually following viral infection.
• Capsular polysaccharide types 14, 4, 1, 6A/6B, 3, 8, 7F, 23F, and 18C
are the most frequent causes of pneumococcal disease.
• Classically, pneumococcal pneumonia produces diffuse involvement
of most of a lobe and more than one lobe may be involved in 10–25%
of cases but spread of consolidation throughout an entire lung is
unusual.

6. Imaging
• Homogenous non segmental , parrenchymal consolidation involving
one lobe, multi lobar involvement is less common.
• More commonly involves lower lobe or posterior segment of upper
lobe.
• Minimal volume loss
• Air bronchogram is common
• Cavitation is rare.
• May present as round pneumonia in children
• Associated with pleural effusion in 60% cases.

7. Pneumococcus pneumonia

9. Staphylococcus aureus
X ray
• Lobular pattern of bilateral , multifocal, patchy heterogeneous ,
segmental air space consolidation.
• Usually lower lobes are involved
• Absent air bronchogram.
• May progress to homogeneous air space consolidation.
• May develop abscess with cavitation.
• Cavity has irregular shaggy internal walls and air fluid level.
• Pleural effusion in 30 -50 %cases , progress to empyema in 50% cases.

10. • CT scan
• Focal or multifocal masses or nodules, may undergo cavitation
• Centrilobular nodules and tree in bud opacities may be present.
• Peripheral wedge shaped opacities with associated feeding vessel is
seen in hematogenous dissemination.
• Pneumatocele common in children . Responsible for spontaneous
pneumothorax.
• Empyema in 20% adult and 75% children

13. Haemophillus influenza
• X ray
• Patchy air space opacities – Bronchopneumonia
• Lobar consolidation in immunosuppressed.
• Reticulonodular opacities associated with consolidation.
• Cavitation is rare.
• Pleural effusion in 40% cases.
• Empyema rare.
• Slow resolution of disease.

15. • Ct scan shows ill defined centrilobular nodules
reflecting peribronchial inflammation.

16. Klebsiella
• X ray
• Usually involves upper lobe
• Homogenous , non segmental lobar consolidation.
• Lobar expansion causing bulging fissure sign is seen.
• Abscess formation in 50% cases.
• Pleural effusion or empyema in 70% cases.

17. • CT
• Necrotizing pneumonia is charecteristic
• Consolidation with or without cavitation.
• Scattered enhancing linear branching structure representing pulmonary
vessel in atelactic or consolidated lung – CT angiogram sign is seen.
• Centripetal resolution (periphery to central) with residual fibrosis is seen.
• Cavitation with narrowed or obliterated feeding bronchus impeding
drainage of necrotic lung.
• Large vessel thrombosis can be seen .

20. Pseudomonas
• X ray and CT finding varies in bacteremic and Non bacteremic
patients.
• Bacteremic patients – patients with systemic toxicity , shock, altered
mental status, non productive sputum.
• Non bacteremic pateints – hemodynamically stable with purulent
sputum.

21. 1) Bacteremic pt
X ray - pulmonary vascular congestion ->pulmonary edema ->
necrotizing bronchopneumonia.
• Within 2-3 days mixed alveolar opacities and cavitation may occur.
• Mutifocal nodules.
• Nodules coalesces to form opacities.

22. CT scan
• Multilobar air space consolidation , upper lobe predilection (82%)
• Nodular opacities in 50% cases
• May be Centrilobular with tree in bud appearance in 64% cases
• Or large randomly distributed nodules in 36% cases.
• Ground glass opacity may be seen .
• Bronchial wall thickening may be present.
• Pleural effusion unilateral in 18% and bilateral in 46% cases

24. 2) Non Bacteremic patients-
X ray
• Bronchopneumonia pattern
• Multifocal , bilateral , nonsegmental consolidation lower lobe more
common.
• Abscess , empyema ,pleural effusion - rare
CT scan
• Reticular or nodular opacities are seen

25. Legionella
• X ray
• Patchy , peripheral non segmental consolidation.
• Progressing rapidly to other lobes and other lung.
• Nodular and mass like consolidation
• Cavitation and lymphadenopathy – Unusual.
• Pleural effusion 50 -66%
• CT
• Sharply demarcated peribronchovascular foci of consolidation with
Ground Glass Opacity

26. • Day 1 Day 2

27. Day 3

28. Tuberculosis
• Primary tuberculosis-
• Consolidation –usually unilateral, dense , homogenous; segmental,
lobar or multifocal . Rapidly progressive cavitary consolidation.
• Lymphadenopathy – typically unilateral usually right hilar, or right
paratracheal more common in children.
• Atelactasis – usually right sided and usually in children.
• Pleural effusion – unilateral and typically self limiting.

29. • Post Primary Tuberculosis
• Consolidation – patchy , heterogenous,involving apical and posterior
segment of upper lobes and superior segment of lower lobes, ill
defined borders, satelite nodules.
• Cavitation –thin or thick walled, focal or multi focal , air fluid level
may be seen.
• Nodular and linear opacities.
• Tuberculoma –solitary or multiple pulmonary nodule variable size
well defined or ill defined margins.may exhibit calcification.
• Pleural effusion unilateral or bilateral.

30. • CT
• Central low attenuation and peripheral enhancement of affected node
• Cavitations are seen
• Linear branching opacities and cetrilobular nodules (2-4mm) tree in bud
appearance is seen due to endobronchial spread of disease associated with
cavitary disease.
• Ill defined nodules (4-8mm)lobular consolidation, thick inerlobular septa.
• Milliary nodules (1-3mm) with random distribution , thick nodular
interlobular septa

31. • Tuberculoma – rim enhancement, calcification, satellite lesion in 80%.
• Bronchial narrowing withmural thickening.
• Upper lobe predominant bronchiectasis.
• Empyema, pleural calcification, bronchopleural fistula – rarely seen

32. PA chest radiograph of a 9-year-old boy with tuberculosis
demonstrates a coalescent right perihilar consolidation
with ipsilateral hilar and mediastinal lymphadenopathy

35. Neoplasms

36. • Solitary Pulmonary Nodule
• Adenocarcinoma
• Squamous cell Carcinoma
• Small Cell Carcinoma
• Large Cell Carcinoma
• Lymphoma
• Metastasis

37. Solitary Pulmonary Nodule
• A solitary pulmonary nodule is defined as a single discrete pulmonary
opacity that is surrounded by normal lung tissue that is not
associated with adenopathy or atelectasis.
• Diameter of SPN should be less than or equal to 3cm
• Incidence 1-2 / 1000 chest X rays

38. D/D for SPN
• Malignant Tumors
• Bronchogenic carcinoma (adenocarcinoma, large cell, squamous, small cell),
Carcinoid, Pulmonary lymphoma, Pulmonary sarcoma, Plasmacytoma Solitary
metastases (colon, breast, kidney, head and neck, germ cell, sarcoma, thyroid,,
melanoma, others)
• Benign Tumors
• Hamartoma, Adenoma, Lipoma
• Infectious Granulomas
• Tuberculosis, Histoplasmosis, Coccidioidomycosis, Mycetoma, Ascaris,
Echinococcal cyst, Dirofilariasis (dog heartworm)
• Noninfectious Granulomas
• Rheumatoid arthritis, Wegener granulomatosis, Sarcoidosis, Paraffinoma, Others
• Miscellaneous
• Bronchiolitis obliterans organizing pneumonia, Abscess, Silicosis, Fibrosis/scar,
Hematoma, Pseudotumor, Spherical pneumonia, Pulmonary infarction,
Arteriovenous malformation, Bronchogenic cyst, Amyloidoma

39. Character Benign Malignant
Age Young Old
Smoking history Absent Present
Size of Nodule Small Large
Radiograph density High (Solid) Low (partly solid ,GGO )
Calcification Present – Diffuse , stippled, laminar
/concentric or popcorn
Absent or Eccentric
Border Well circumscribed , round
Appearance
Lobulated border , Irregular
Appearance
Margins Smooth Spiculated
CT volume doubling Time , change
in density
Less than 20 days OR more than
400 days
60 – 80 days sq cell carcinoma
120 days Adenocarcinoma
30 days Small cell carcinoma

40. • Other features indicating malignancy are
• Pleural Retractoins
• Feeding vessel (vessel sign)
• Vascular convergence
• Dilated bronchus leading into nodule
• Pseudocavitation & True Cavitation

41. Types of nodules

42. Calcification

43. Benign
Nodules

48. Adenocarcinoma
• 4 entity of Adenocarcinoma is identified on CT
• 1. Atypical Adenomatous hyperplasia of Lung (<0.5cm)
• 2. Adenocarcinoma In Situ (0.5 – 3cm)
• 3. Minimally Invasive Adenocarcinoma (<3cm, with invasion <0.5cm)
• 4. invasive Adenocarcinoma

53. Squamous Cell Carcinoma
• Squamous cell carcinoma is defined as a malignant epithelial tumor
showing keratinization and/or intercellular bridges.
• It has rapid local growth and relatively late distant metastases.

54. Imaging
• Frequent secondary atelectasis (absent air bronchograms),
obstructive pneumonia, or mucoid impaction; may be dominant
radiologic abnormalities
• Central mass
• Bronchial wall thickening; thickened (>3 mm) intermediate stem line
(i.e., posterior wall of the bronchus intermedius) (lateral radiography)
• Peripheral lung nodule or mass
• Cavitation
• Lymphadenopathy

57. CT chest
• Irregular central mass with abrupt obstruction of bronchial lumen
• Post-obstructive consolidation , atelectasis ; contrast administration
may help differentiate tumor from adjacent consolidation and
atelectasis , as tumor typically enhances less than atelectatic lung
• Bronchial wall thickening
• Peripheral mass or nodule
• Cavitation
• Lymphadenopathy

59. Drowned Lung

60. Small Cell Carcinoma
• Small-cell carcinoma is a malignant epithelial tumor consisting of
small cells with scant cytoplasm, ill-defined cell borders, finely
granular nuclear chromatin, and absent or inconspicuous nucleoli.
Chest X ray
• Central mass
• Lymphadenopathy
• Peripheral nodule rarely.

62. Large cell carcinoma
• Large-cell neuroendocrine carcinoma is defined as “a large-cell
carcinoma showing histologic features such as organoid nesting,
trabecular, rosette-like and palisading patterns that suggest
neuroendocrine differentiation and in which the latter can be
confirmed by immunohistochemistry or electron microscopy.
• It is an aggressive cell type of lung cancer that accounts for
approximately 9% of all lung carcinomas.
• These neoplasms are characterized by rapid growth and frequent
metastases at presentation.

64. Lymphoma
• Focal or multi-focal nodules, masses, or consolidations
• Ground glass opacities, CT halo sign
• Air bronchograms (90%) ; bronchial stretching, narrowing or
dilatation; bubble-like lucencies; cavitation
• Reticular opacities
• Pleural effusion in up to 10% of cases
• Lymphadenopathy in 5–30% of cases

66. Metastasis
• Bilateral multifocal well-defined nodules/masses; spherical morphology
• Variable size
• Multi-focal opacities with ill-defined borders; may mimic air space disease
• Most numerous in the lower lobes
• May exhibit associated hilar/mediastinal lymphadenopathy
• May exhibit associated pleural effusion
• Rarely ◦ Cavitation, ◦ Calcification ◦ Solitary nodule/mass ◦ Endobronchial
lesion; may exhibit atelectasis/consolidation ◦ Lymphangitic carcinomatosis

69. THANK YOU