Respiratory radiology Flashcards
What is a silhouette?
air sitting next to something solid
How do we know that the person has properly inspired prior to taking the CXR (PA)?
you can see 6-7 anterior ribs on the X-ray, and the heart is not enlarged; and 10 posterior ribs
What do you normally see in lung fields as opaque structures?
pulmonary arteries and pulmonary veins + soft tissues
What is the cardiothoracic ratio normally on PA film?
<50%
What can cause decreased and increased lung volumes?
Pulmonary fibrosis and COPD respectively. A hyperinflated lung in COPD–> lung volumes expand sagittally as well as anteriorly. The diaphragm flattens and appears serrated. Greater than 2cm from costophrenic angle to cardiophrenic angle
where would you look for right middle lobe?
Under the right axilla.
what can cause increased opacity in the lung fields?
pleural fluid, atelectasis, oedema/consolidation in airspaces, tumours, abscesses
Pleural effusion description
Usually basal–> blunting of costophrenic angle. Has a curving up meniscus, and appears less opaque more superiorly. Can be caused by infection or cardiac failure.
What can cause alveolar opacity?
pulmonary oedema and consolidation
what can cause interstitial opacity?
pulmonary oedema, pulmonary fibrosis
What is another cause of lung opacity?
tumour or metastases
What can cause increased lucency (blackness) in lung fields?
pneumothorax, bullous emphysema
Why might we need an expiratory chest Xray?
if we suspect a pneumothorax, the features of pneumothorax will be more exaggerated.
What do we do if we suspect a PE?
CT pulmonary angiogram
If we see tubular opacities on CXR…
think bronchiectasis
CT- what is the units of plain water and blood?
plain water= zero units, blood= 40-50 units
what do we see in COPD on a plain CXR?
lung hyperinflation, flattened diaphragm, small heart on PA X-ray. On lateral CXR, increased AP diameter
would you see the right ventricle on a frontal projection?
no. but you can see it on a lateral CXR, bc it’s retrosternal
which hemidiaphragm is elevated?
right bc of liver
Consolidation that obscures the right upper mediastinal silhouette?
means that consolidation in the right upper lobe
Consolidation that obscures the right hemidiaphragm silhouette?
means that consolidation in the right lower lobe
Consolidation that obscures the right side of the cardiac border?
means that consolidation in the right middle lobe
If you have consolidation in the left lingula lobe- which silhouette do you obscure?
left cardiac border
2 main causes of bilateral airspace opacities post operatively?
Aspiration pneumonia or fluid overload due to fluid or blood transfusions.
What do you think the lateral CXR show for Mitral valve disease show?
The oesophagus is indented as the left atrium grows posteriorly.
What are 3 causes of massive cardiomegaly
- cardiomyopathy, 2. pericardial effusion
3. mixed valvular disease
what would you see for radiation pneumonitis?
a pleural effusion in the area where radiation is targeted.
what would you see for pulmonary fibrosis?
Decreased lung volumes + diffusely increased interstitial opacity= pulmonary fibrosis
what would you see in an X-ray for COPD?
Hyper inflated lungs, flattened diaphragm. Lateral chest X-ray shows barrel chest–> increased AP diameter. Increased lucency. Small cardiac size.
what would you think if you see a cavitating lesion on CXR?
you would think:
- TB
- Cancer
- Pulmonary abscess
what would you think if you saw widespread consolidation on a CXR?
ARDS- acute respiratory distress syndrome= diffuse alveolar damage
how can you tell which hemidiaphragm is which for lateral CXR
heart is attached to left hemidiaphragm so look for that
what is the aortopulmonary window? what is its clinical significance?
between aorta and pulmonary artery on CXR frontal. If something in it the space- abnormal, possibly enlarged lymph node
which hilum is higher?
left hilum
