Chest imaging Lecture two - PowerPoint Presentation

1. Chest imaging Lecture twoDr. Marwa majid Aladhab

2. Homework

3. Case 1

4. Case 2

5. Case 3

6. Objectives

7. Anatomically, functionally and radiologically the lungs may be divided into two compartments:1. The interstitium: soft tissue structures between the alveoli, and includes branching distal bronchi and bronchioles, accompanying arteries, veins and lymphatics, plus supporting connective tissue.2. The alveoli or airspaces: arise from the respiratory bronchioles and alveolar ducts.

8. Common findings on CXR

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10. 1.Diffuse pulmonary shadowing A- alveolar opacificationB- interstitial shadowingAlveolar opacification (consolidation)Causes: edema, inflammatory fluid, blood, protein or tumour cells.All have the same soft tissue density on CXR so the appearances are often non-specific.Definite diagnosis is usually only made where the CXR findings are correlated with the clinical signs and symptoms.

11. CXR signs of alveolar shadowing:• Opacity tends to appear rapidly after the onset of symptoms• Fluffy, ill-defined areas of opacification• Areas of consolidation tend to coalesce• Air bronchograms

12. Air bronchogramair-filled bronchi can be seen as they are outlined by surrounding consolidated lung.air bronchograms are not seen in pleural or mediastinal processes.

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14. Patterns of distribution of alveolar shadowing• Segmental or lobar distribution• Bilateral opacification spreading from the hilar regions into the lungs with relative sparing of the peripheral lungs, sometimes referred to as a ‘bat wing’ distribution• Bilateral opacification involving the peripheral lungs with relative sparing of the central regions, sometimes referred to as ‘reversed bat wing’ distribution.Alveolar opacification may be acute or chronic.

15. Causes of alveolar opacificationSegmental/lobar alveolar pattern:• Pneumonia• Segmental/lobar collapse• Pulmonary infarct• Alveolar cell carcinoma• Contusion

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17. Acute bilateral central ‘bat wing’ pattern:• Pulmonary edema• Pneumonia: Pneumocystis jiroveci pneumonia; TB; viral pneumonias; Mycoplasma• Pulmonary hemorrhage: Goodpasture’s syndrome; anticoagulants; bleeding diathesis: hemophilia, disseminated intravascular coagulation (DIC).

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19. Chronic bilateral central ‘bat wing’ pattern:• Atypical pneumonia: tuberculosis (TB), fungi• Lymphoma/leukaemia• Sarcoidosis: interstitial form much more common• Pulmonary alveolar proteinosis• Alveolar cell carcinoma: localized form more common.

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21. Reversed ‘bat wing’ pattern:• Loeffler’s syndrome: transient pulmonary infiltrates associated with blood eosinophilia• Chronic organizing pneumonia (COP)• Wegener granulomatosis• Fat embolism: occurs 1–2 days after major trauma, particularly with fractures of the large bones of the lower limbs.

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23. Interstitial opacificationThree patterns: linear (reticular), nodular and honeycomb pattern. These patterns may occur separately, or together in the same patient with considerable overlap in appearances.

24. Linear pattern• Network of fine lines running through the lungs• Lines are due to thickened connective tissue septa• Kerley A lines: long, thin lines in the upper lobes• Kerley B lines: short, thin lines predominantly in the lower zones extending 1–2 cm horizontally inwards from the lung surface.

25. Nodular pattern• Nodules due to interstitial disease are small (1–5 mm), well defined and not associated with air bronchograms.• Nodules tend to be very numerous and are distributed evenly throughout the lungs.

26. Honeycomb pattern• Honeycomb pattern represents the end stage of many of the interstitial processes. May also be seen with tuberous sclerosis, amyloidosis, neurofibromatosis and cystic fibrosis.• Honeycomb pattern implies extensive destruction of pulmonary tissue.• Cysts that range in size from tiny up to 2 cm in diameter replace the lung parenchyma. These cysts have very thin walls.• Normal pulmonary vasculature cannot be seen.• Pneumothorax is a frequent complication of honeycomb lung.

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28. Causes of interstitial opacificationThe list of interstitial disease processes is extensive. CXR appearances are often non-specific.The clinical presentation, time course (acute or chronic) and HRCT findings help to slightly shorten the differential list.Acute interstitial shadowing:• Interstitial edema: Kerley B lines, cardiac enlargement; pleural effusions• Acute interstitial pneumonia: usually viral.

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30. Subacute interstitial shadowing:• Lymphangitis carcinomatosis: due to direct malignant infiltration and obstruction of the lymphatic pathways in the pulmonary interstitium• In patients with a history of carcinoma, lymphangitis carcinomatosis may cause localized or diffuse interstitial shadowing• Prominent linear and nodular shadowing with Kerley B lines, often associated with mediastinal and/or hilar lymphadenopathy

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32. Chronic, upper zones:• TB: upper lobe fibrosis; associated calcification in cavities• Sarcoidosis: often associated with hilar lymphadenopathy, although pulmonary involvement alone occurs in 25 per cent of cases• Silicosis: associated with hilar lymph node calcification and enlargement; may also beassociated with large confluent masses, i.e. progressive massive fibrosis (PMF)• Extrinsic allergic alveolitis• Bronchopulmonary aspergillosis• Langerhans cell histiocytosis.

33. Chronic, lower zones:• Usual interstitial pneumonia (UIP)• Asbestosis: may be associated with pleural plaques and calcification, particularly of the diaphragmatic pleura• Connective tissue disorders: systematic lupus erythematosis (SLE); systemic sclerosis (scleroderma); dermatomyositis/polymyositis.

34. 2. Lobar pulmonary consolidation Same radiographic findings of alveolar opacification localized to a lobe or segment. Consolidation of a pulmonary lobe or segment is usually due to pneumonia, with other less common causes, such as pulmonary infarct or contusion, usually differentiated on the basis of clinical history. Organisms that commonly cause pneumonia: Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae and Mycoplasma pneumoniae. Early subtle areas of alveolar shadowing may progress to dense lobar consolidation. Expansion of a lobe with bulging pulmonary fissures may be seen with Klebsiella.

35. Necrosis and cavitation may complicate severe cases of lobar pneumonia.Small pleural effusions commonly accompany pneumonia.More aggressive organisms, such as Staphylococcus aureus and Pseudomonas may cause more extensive consolidation. This may involve multiple lobes, with cavitation leading to abscess formation.Other complications of pneumonia include empyema and bronchopleural fistula.

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37. Localizing signs

38. Consolidation adjacent to fissuresStraight margins occur in the lungs at the pulmonary fissures. If an area of consolidation or collapse has a straight margin, that margin must abut a fissure, and this can help in localization

39. Lobe of lungCause of straight margin Rt upper lobe Horizontal fissure inferiorly on PA film. Oblique fissure posteriorly on lateral filmRt middle lobeHorizontal fissure superiorly on PA film. Oblique fissure posteriorly on lateral filmRight lower lobeOblique fissure anteriorly on lateral film. Collapse causes rotation and visualization of the oblique fissure on the PA filmLeft upper lobeOblique fissure posteriorly on lateral filmLeft lower lobeOblique fissure anteriorly on lateral film. Collapse causes rotation and visualization of the oblique fissure on the PA filmLocation of pulmonary consolidation or collapse according to fissure abutment

40. Silhouette sign

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42. Increased density of lower thoracic spine on the lateral viewOpacification in the right or left lower lobes may produce an apparent increase in density of the lower thoracic vertebral bodies. This may be the most obvious radiographic sign of lower lobe pneumonia

43. Thank you