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Basic Interpretation of
Chest X-Ray
Dr.Vikram Patil
Assistant Professor, Radiology
JSS Medical College and Hospital, Mysuru
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Air Fat Soft tissue Bone Metal
least opaque to most opaque
most lucent to least lucent
Black to White
Different tissues in our body absorb X-rays
at different extents
Before we start :
5 Radiographic Densities
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Before Interpreting the Radiograph …
1. Patient identification details
2. X-Ray view-PA or AP….
3. Breath : Inspiration or Expiration
4. X-ray penetration : Under or Over penetrated
5. Rotation
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PA view AP view
Scapula Seen in periphery of thorax Seen over lung fields
Clavicles Project over lung fields Above the apex of lung fields
Ribs Posterior ribs distinct Anterior ribs are distinct
Marker PA AP
View
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Inspiration Expiration
Good Inspiration:
• 6 anterior ribs visible
• 10 posterior ribs visible
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Penetration
Over-penetrated Under-penetrated
If intervertebral disc are very
clearly seen in the film
If intervertebral disc are not
seen in the film
Correct exposure : Barely able to see the intervertebral disc through the heart
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Abnormal Chest X-ray
• Radiopacity (whiteness) = increased density
• Radiotranslucency (blackness) = decreased density
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Radio-opacity
• Without Volume loss
– Pneumonia, Pulmonary edema, hemorrhage, mass
• With Volume loss
– Atelectasis, Collapse
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Lobar Pneumonia
• Involves single lobe
• Unilateral
• Air bronchogram
Interstitial Pneumonia
•Involves interstitial space
•Ground glass appearance
•Bilateral, symmetrical
Bronchopneumonia
•Central bronchi involved
•Patchy bilateral disease
•Asymmetrical
•Peribronchial cuffing
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Subtypes of Interstitial opacities
Reticular
Too many lines
Nodular
Too many dots
Reticulo-nodular
Too many lines and dots
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Silhouette Sign
• Loss of normally visible border of an intrathoracic
structure caused by an adjacent pulmonary density
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Atelectasis- partial collapse Lobar collapse -collapse of an entire lobe
•Elevation of the ipsilateral hemidiaphragm
•Crowding of the ipsilateral ribs
•Shift of the mediastinum towards the side
•Crowding of pulmonary vessels or air bronchograms
•Hyperinflation of adjacent normal lung
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Golden S sign
• Central mass obstructing the upper
lobe bronchus .
• Should raise suspicion of a primary
Bronchogenic Carcinoma
• First described by R Golden
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Sarcoidosis
Staging
I Bilateral Hilar adenopathy
II Bilateral Hilar adenopathy
with diffuse pulmonary
infiltrates
III Diffuse pulmonary
infiltrates without hilar
adenopathy
IV Severe fibrosis
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Pulmonary Arterial Hypertension
Enlargement of the pulmonary trunk and main pulmonary arteries
Disproportionately small peripheral vessels
Oligemic lungs
Prune tree appearance
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Pulmonary Venous Hypertension
Upper lobe veins in first
intercostal space >3mm
Interstitial edema with
Kerley B lines
Airspace edema with
confluent airspace opacities
PCWP mildly increased PCWP around 20 PCWP around 25
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Pulmonary Edema ARDS
Distribution Bat winged pattern Diffuse bilateral coalescent
opacities
Time Develops over 1 week Develops by 12-24 hrs of insult
Cardia Cardiomegaly No Cardiomegaly
Kerley lines Present Absent
Pleural effusions Usually Present Usually absent
Air Bronchogram Present Absent
On Diuretic Therapy Usually resolves Fairly constant over time
Pulm Edema
vs ARDS
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Air at Unusual
Locations
Subcutaneous Emphysema
Perforation
Pneumomediastinum
Pneumopericardium
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ICU- Tubes & Lines
Tip at Junction of SVC &
Right atrium
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Mediastinal abnormalities
• Hilum overlay sign:
On a frontal Chest X-ray, Mass projected at the level of the
hilum is either anterior or posterior to the hilum.
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Posterior mediastinal mass
Spine Sign
Cervicothoracic sign
Mediastinal masses
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EXTRAMEDULLARY HEMATOPOESIS
• Smooth lobular mass in paravertebral
gutter, in lower thorax
• Bilateral and symmetrical
• Due to compensatory expansion of
marrow in congenital hemolytic anaemia
Thoraco-abdominal sign:
Lesion extends below the dome of diaphragm-Lesion in the posterior chest
Lesion terminates at the dome –Lesion in the anterior chest
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Take home message
• Look carefully for patient identification details and technical issues
• Be systematic in approach
• It’s a chest X-ray, not a lung x-ray.
• Concentrate on hidden areas
• Compare with old films and lateral films
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Thank you
Editor's Notes
Ensure trachea is visible and in midline
Trachea gets pushed away from abnormality, eg pleural effusion or tension pneumothorax
Trachea gets pulled towards abnormality, eg atelectasis
Trachea normally narrows at the vocal cords
View the carina, angle should be between 60 –100 degrees
Beware of things that may increase this angle, eg left atrial enlargement, lymph node enlargement and left upper lobe atelectasis
Follow out both main stem bronchi
Check for tubes, pacemaker, wires, lines foreign bodies etc
If an endotracheal tube is in place, check the positioning, the distal tip of the tube should be 3-4cm above the carina
Check for a widened mediastinum
Mass lesions (eg tumour, lymph nodes)
Inflammation (eg mediastinitis, granulomatous inflammation)
Trauma and dissection (eg haematoma, aneurysm of the major mediastinal vessels)
Usually positioned with one-third of its diameter to the right, and two-thirds to the left of the thoracic vertebrae spinous processes.
The right atrium makes up the right heart border and the left ventricle the left heart border.
Poor distinction of the right heart border suggests consolidation of the right middle lobe.
Poor distinction of the left heart border suggests lingular consolidation.
Cardiothoracic ratio (CTR):
Compares the transverse diameter of the heart to the internal thoracic diameter (inner aspect of the ribs) at its widest point.
Should be less than 0.5 (50%) on a PA CXR, but may appear magnified on AP films.
Abnormally increased CTR occurs with ventricular dilatation (usually left), cardiac failure and a pericardial effusion.
The right is usually higher than the left by 1–3 cm.
Pleural effusions will blunt the costophrenic angles. Loss of diaphragmatic outline indicates fluid, consolidation or collapse of adjacent lung (i.e. of the right or left lower lobe).
Both hemidiaphragms are flat in chronic obstructive limitation disease such as emphysema.
Free gas under a diaphragm on an erect film indicates rupture of an abdominal hollow viscus, such as the duodenum or small or large intestine. It also occurs after laparoscopy with the deliberate introduction of a pneumoperitoneum.
evel with the T6–7 intervertebral space on either side of the mediastinum, and are made up of the pulmonary arteries and veins.
The left hilum is usually higher (2cm) and squarer than the V-shaped right hilum.
Unilateral or bilateral hilar enlargement can be caused by
Enlarged hilar lymph nodes (e.g. sarcoidosis or infection)
Hilar malignancy (e.g. small-cell carcinoma)
Vascular disease (e.g. pulmonary hypertension or proximal pulmonary artery aneurysms).
Superior mediastinum:Should have a width <8 cm on a PA CXR.
A widened mediastinum can be associated with:
AP CXR view, which magnifies the heart and mediastinal structures
Unfolded aortic arch (not pathological) or a thoracic aortic aneurysm
Mediastinal lymphadenopathy, retrosternal thyroid, thymoma (can be particularly massive in children)
Paravertebral mass, oesophageal dilatation
Ruptured aorta in deceleration trauma from vehicle crash or fall from a height.
Look for evidence of mediastinal emphysema (abnormal air) secondary to:
Penetrating wound ± lacerated lung
Perforation of oesophagus or trachea
Asthma and whooping cough (pneumomediastinum).
Frontal chest radiograph showing a questionable mass near the right cardiophrenic angle
Except in the case of very advanced disease with bulla formation, chest radiography does not image emphysema directly, but rather infers the diagnosis due to associated features 2-3:
It should be remembered, however, that the most common plain film appearance of COPD is "normal" and the role of chest radiography is to eliminate other causes of lung symptoms such as infection, bronchiectasis or cancer
Multiple rib fractures complicated by left hemidiaphragm injury, left pneumothorax (treated by drain) and widespread surgical emphysema (tracking subcutaneous air)