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Chest Imaging
II
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Radiological semiology of
pulmonary pathology
• Pulmonary opacity
• Pulmonary hyperlucency
• Changes of pulmonary picture
• Changes of pulmonary hilum
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Pulmonary opacity is a nonspecific term describing an area
of increased pulmonary attenuation caused by an
intraparenchymal process resulting in the decreased ratio of
gas to soft tissue (blood, lung parenchyma and stroma) in the
lung.
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• Identify the lesion
• Localise the lesion
• Describe the lesion
• Formulate conclusion, give differential
diagnosis
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Pulmonary opacity
• Number (single / multiple, disseminated)
• Location (unilateral / by ribs / regions / lobes / segments)
• Dimensions (large (total, subtotal) / limited to lobe or lobar segment /
mass / nodular)
• Shape (rounded / ring-shape (cavitary) / linear / triangle / irregular)
• Borders (well-defined, regular or irregular / ill-defined )
• Structure (homogeneous / heterogeneous)
• Intensity (subcostal / costal / supracostal) compared to the rib opacity
• Relation to the mediastinum (without displacement / shifting(pushing/
pulling))
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The silhouette sign
• Loss of an interface (outline) of anatomical
structures resulting from the juxtaposition
of adjacent pathology of similar
radiographic density
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Total and subtotal opacity
Unilateral opacity shifting mediastinum to the opposite side, homogenous
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Total and subtotal opacity
Unilateral opacity shifting mediastinum to the same side, homogenous
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Total and subtotal opacity
shifting mediastinum to the opposite side shifting mediastinum to the same side
(mass effect – pleural effusion) (volume loss – collapse of the lung,
atelectasis)
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Total and subtotal opacity
shifting mediastinum to the opposite side shifting mediastinum to the same side
(mass effect – pleural effusion) (volume loss – collapse of the lung,
atelectasis)
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The meniscus sign
• If the patient is upright when the radiograph
is taken, then fluid will surround the lung
base forming a 'meniscus' – a concave line
obscuring the costophrenic angle and part or
all of the hemidiaphragm.
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Pleural effusion
• Fluid accumulation in the pleural space
• Radiological criteria:
– Opacity
• in costophrenic angle in PA view, depending on the
quantity of the effusion (loss of costophrenic angle)
• allong sides in lateral decubitus position
– Meniscus sign
– Silhouette sign (loss of diaphragmatic and cardiac
silhouette)
– Shifting the mediastinum to the opposite side
(depending on the quantity of the effusion )
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Meniscus sign (bilateral) – pleural effusion
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Small Pleural Effusion
Normal:
Sharp Angles
Blunted posterior costophrenic sulcus
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Silhouette sign (loss of left diaphragmatic and cardiac
silhouette) – pleural effusion
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Opacity allong sides in lateral decubitus position
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Consolidation
• Filling of the alveoli and bronchioles in the lung with pus (pneumonia), fluid
(pulmonary oedema), blood or neoplastic cells
• Causes of Pulmonary Consolidation
– Pneumonia - lobar pneumonia, bronchopneumonia, fungal pneumonia, viral
pneumonitis, tuberculosis
– Fluid - pulmonary oedema (cardiogenic / non-cardiogenic)
– Neoplasm - primary lung cancer, metastases, lymphoma
– Vascular - pulmonary haemorrhage, infarction, contusion, embolism
– Inflammation - systemic lupus erythematosus, granulomatosis with
polyangiitis etc.
– Aspiration pneumonitis, Sarcoidosis, Cryptogenic pneumonia
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Limited opacity
Right middle lobe consolidation:
•silhouette loss of the right cardiac
border
•intact diaphragmatic silhouette .
•without mediastinal displacement,
•heterogenous,
•ill- defined borders
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Limited opacity RUL
without mediastinal displacement,
heterogenous,
ill- defined borders
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consolidation in left lower lung field
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LUL Consolidation
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RML Consolidation
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Consolidation
• Lobar consolidation:
– Alveolar space filled
with inflammatory
exudate
– Interstitium and
architecture remain
intact
– The airway is patent
– Radiologically:
• A density corresponding
to a segment or lobe
• Airbronchogram, and
• No significant loss of
lung volume
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Consolidation
• Lobar consolidation:
– Alveolar space filled
with inflammatory
exudate
– Interstitium and
architecture remain
intact
– The airway is patent
– Radiologically:
• A density corresponding
to a segment or lobe
• Airbronchogram, and
• No significant loss of
lung volume
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Air Bronchogram
•Tubular outlines of the smaller airways.
•Appear when the alveoli surrounding the airway collapse or are filled
with fluid.
•Air bronchograms will not be visible if the bronchi themselves are
opacified (e.g. by fluid) and thus indicate patent proximal airways.
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CT pulmonary window . Segmental opacity
(consolidation), air bronchogram.
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CT mediastinal window . Segmental opacity
(consolidation), air bronchogram.
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AIR BRONCHOGRAM
Air containing bronchus peripheral to the hilum surrounded by
airless lung
CXR CT Scan
Air Bronchogram
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Pneumonia
• Consolidation
• Air bronchograms would confirm an alveolar process.
• No loss of lung volume (may even be increased).
• Usually all radiographic abnormalities should
disappear after 6 weeks of appropriate antibiotic
therapy.
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Pneumonia RML
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Right Upper Lobe Pneumonia
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Left Lingular Pneumonia
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Left Lower Lobe Pneumonia
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Pneumonia RLL
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Pneumonic infiltration of
the right middle lobe
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Atelectasis
• Collapse of lung parenchyma resulting from an obstruction of the air
ways affecting part or all the one lung.
• No ventilation to lobe or segment beyond the obstruction. Trapped
air is absorbed into the pulmonary circulation.
• Radiological signs
– Lobar / segmental opacity
– Volume loss:
• displacement of fissures
• mediastinal & hilar displacement to the same side
• elevation of hemidiphragm
– Compensatory hyperinflation of normal lung
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Atelectasis
• Loss of air
• Obstructive
atelectasis:
– No ventilation to the
lobe beyond
obstruction
– Radiologically:
• Density corresponding
to a segment or lobe
• Significant loss of
volume
• Compensatory
hyperinflation of normal
lungs
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Atelectasis
• Loss of air
• Obstructive
atelectasis:
– No ventilation to the
lobe beyond
obstruction
– Radiologically:
• Density corresponding
to a segment or lobe
• Significant loss of
volume
• Compensatory
hyperinflation of normal
lungs
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LUL Atelectasis: Loss of heart borders/silhouetting.
Notice over inflation on unaffected lung
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Collapse RUL
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Collapse LUL
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Indistinct Right
Heart Border
Right Middle Lobe Atelectasis
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Right Middle Lobe Atelectasis
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Rounded opacity
• Opacity (mass) larger than 3 cm in diameter.
• Solitary or multiple
• without mediastinal displacement, homogenous structure,
• well-defined regular borders
Causes
• Benign tumors, e.g. hamartoma
• Malignant tumors, e.g. bronchial carcinoma, metastases
• Infection, e.g. pneumonia, abscess, tuberculosis, hydatid cyst
• Infarction
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Rounded opacity
without mediastinal displacement,
homogenous structure,
well-defined regular borders
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Rounded opacity
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Lung Mass
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Cavitary lesions of the lung
(ring-shaped opacity)
• A gas containing space within the lung surrounded by a
complete wall.
• Occurs when an area of necrosis communicate with a
patent airway.
• Features
– wall thickness, outline, fluid level, surrounding lung
Causes
• Abscess.
• Neoplasm.
• Cavitating pneumonia.
• Cavitations in infarcts.
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Ring-shaped
opacity
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Ring-shaped opacity
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Multiple abscesses.
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Cavitating lung lesion
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Bronchiectasis
• Irreversible abnormal dilatation of the bronchial tree,
leading to a build-up of excess mucus that can make the
lungs more vulnerable to infection.
Causes of Bronchiectasis
• Structural
• obstruction (carcinoma, foreign body)
• Infection, e.g. childhood pertussis or measles,
tuberculosis, pneumonia
• Immune, e.g. hypogammaglobulinaemia, allergic
bronchopulmonary aspergillosis
• Metabolic, e.g. cystic fibrosis
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Bronchiectasis
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Cystic lesion in the left lower pulmonary field – pneumatocele
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Nodular opacity
• Opacities less than or equal to 3cm in diameter
• Solitary pumonary nodule
– Benign tumor
– Malignant tumor, secondary (metastasis)
– Granuloma, tuberculosis, histoplasmosis, sarcoidosis etc.
– Lung cyst, infarct, hematoma, amiloidosis etc.
• Multiple pumonary nodules
– Sarcoidosis, pneumoconiosis (silicosis, asbestosis),
tuberculosis, infective bronchiolitis, fungal infection, metastases,
pumonary lymphoma, pumonary amiloidosis
• Miliary opacities – multiple small shadows 1-4mm in diameter
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Nodular opacity
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Right upper lower lobe pulmonary nodule
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Nodular opacity
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Solitary Pulmonary Nodule can
be:
Malignant: Adenocarcinoma Benign: Densely calcified nodule
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Metastatic Lung Cancer: multiple nodules seen
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Miliary opacities
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Military T.B.
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NODULAR PATTERN
Collection of innumerable small, linear and nodular opacities
together producing a net with small superimposed nodules.
CT
CXR
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Reticular and linear opacification
• Due to a pathological process centered in or around the pumonary
interstitium. This includes thickening of any of the interstitial
compartments by blood, water, tumor, cells, fibrous disease.
Pulmonary edema
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Steps (order) of radiograph reading and reporting
• 1 Patient information
• name, date of birth, sex, old films
• 2 Imaging techique data
• time of image acquisition, radiograph, projection (view), contrast
materials and other medicantions administered
• 3 Quality control
• rotation (is the film centered?)
• penetration (is it exposed properly?)
• inspiration (is it a good inspiration film?)
• 4 Observations, description of findings
• soft tissues, bony structures
• mediastinum
• diaphragms, costophrenic angles
• lung fields
• 5 Summary (impression, conclusion)
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