2. Densities
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•
•
•
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Four densities on XR
Black – air/gas
Dark grey – fat
Light grey – fluid/solid organ
White – bone/calcium
Increasing
opacification
3. CXR
• Rule No 1! – always check name of patient
and date
• Check orientation (L & R labeled correctly)
• Projection (PA or AP, lateral, decubitus,
supine)
• Accurate assessment of heart size and
mediastinum on PA views
• All supine/portable - AP
4. CXR - systematic
• ABCDE for both frontal & lateral projection
• A – airways
– Trachea/central bronchi midline or just to right, no narrowing, carinal
angle <90°
• B – breathing/lungs
– Parenchyma – too white or too black?
• Look at the fissures
– Bones – ribs, vertebrae, humeri clavicles, scapulae – for fractures,
lytic(black), sclerotic (white) lesions, vertebral body heights
• C – cardiac/vessels
– Cardiac silhouette & Mediastinum contours & width
– Hilum – normal hilar shadow made up of vessels, Lt is higher than right
by 0-2.5 cm. Must have concave shape
– Pulmonary vessels – upper zone vessels vessels smaller than lower
5. CXR - systematic
• D – look under the diaphragm
– free gas – perforated viscus
– Costophrenic angle for pleural effusion
• E – extremities
– The corners of the film
• Line position
• Hidden areas: lung apices, behind the heart,
breast shadows, paravertebral, thyroid
9. Heart
• Cardiothoracic ratio (CTR)
– <50% adults
– PA film – AP magnifies heart
– Causes of increased CTR
• Obesity, pectus, portable film, cardiomegaly,
pericardial effusion
• Shape
• Valve calcification
10. Lungs
• Too black
• Too white
– Opacity, density, infiltrate, mass/nodule
• Alveolar air cells
– Normally contain air (black)
– Cells eg infection/inflam pus, tumour, eosinophils
– Fluid eg aspiration, drowning, oedema, haemorrhage
• Interstitial
• Collapse V consolidation
– Volume loss: mediastinal shift, fissures, diaphragm,
hilum, rib crowding
– Air bronchograms
11. Silhouette sign
• When air in alveoli replaced with fluid/cells
contrast between the lung and the
neighbouring structure (heart, diaphragm) is
lost and borders become indistinct.
• Use the silhouette sign to determine which
lobe of the lung consolidation is in.
25. The Black Lung
• First consider Rotation:
– (look at the clavicles)
– The lung closer to the film plate will absorb
more of the x-rays and so be whiter, whilst the
lung further away allows distance for scattered
rays to get through, and so will be blacker
31. Pulmonary embolism
• Abnormalities seen on CXR in PE
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–
–
–
–
–
–
–
MORE OFTEN NORMAL – never forget this!!
Segments/subsegments of linear atelectasis
Raised hemidiaphragm
Focal region of hyperlucency (oligaemia)
“Westermark’s sign” – black area of lung seen in
only 2%
Peripheral foci of consolidation (infarction) e.g.
Hampton’s Hump. <10% show infarction.
Dilated central arteries due to arterial hypertension.
Abrupt cut-off of a vessel – only if in the central
arteries
Pleural effusion
34. Pleural Plaques
• Associated with asbestos exposure
• Thickening of the parietal pleura which
calcifies, especially seen over the
diaphragmatic surface as dense linear
bands.
• Does NOT equal asbestosis, which is
pulmonary parenchymal disease related to
asbestos exposure
– can occur together.
36. • Hilar Enlargement
– unilateral or bilateral
– Look for the convex contour
• Neoplasm:
– central bronchogenic tumour itself, or lymphadenopathy. e.g. Ca
Bronchus, lymphoma, Lymphangitis carcinomatosis
•
•
•
•
•
Infective e.g. TB (usually unilateral), Mycoplasma, Viral in children
Sarcoidosis rarely unilateral, very symmetrical
Post-stenotic dilatation of pulmonary artery
Pulmonary artery aneurysm (very rare)
All causes of pulmonary arterial hypertension: primary (idiopathic) or
secondary e.g. COAD, long- term PE, chronic left to right cardiac
shunt.
37. Mediastinum
•
•
•
•
•
•
•
When reviewing CXR, don’t forget this
region, which contains the oesophagus,
the trachea, the aorta, the thymus
Differential Diagnosis of an anterior
Mediastinal mass: “The 4 Ts”
Thymoma
Thyroid goitre
Teratoma
Terrible Lymphoma
Assessing the mediastinal width after
severe road trauma is important to assess
for
–
•
aortic rupture. However, these films are
always supine (so AP) so very variable!!
In practice, if the widest part of the upper
mediastinum is >30% of the total thorax
diameter at that level, suspect aortic
injury if clinically possible. However,
NEVER ignore high clinical suspicion
even if the xray seems normal.