IOD Chest Imaging Flashcards
What does consolidation mean?
material filling in the alveoli
makes affected area appear white on CXR-more dense
air bronchograms?
large airways not filled with material but air which creates these if smaller airways are filled
Causes of consolidation?
Pus Pneumonia Water Pulmonary oedema Blood Trauma Vasculitis Cells Eg Tumour
Silhouette Sign?
If there is consolidation in lung that is against another structure eg heart, the normal interface between air and soft tissue is lost so the border of that structure is no longer visible
left diaphragmatic border SS?
Left lower lobe consolidation
apex SS?
lingula consolidation
right border SS?
Right middle lobe consolidation
Right diaphragmatic border SS?
right lower lobe consolidation
infections?
Lobar pneumonia- commonly bacterial cause eg strep pneumoniae
Pulmonary TB?
Upper lobe consolidation
Cavity formation
Hilar lymphadenopathy
lung cancer?
Usually presents as a nodule (<3cm) or mass (>3cm) on chest x-ray
May be primary lung cancer- more common in smokers
May be secondary- metastases from elsewhere, more likely if multiple
Review areas?
clavicles/apex
hilar
behind heart
below diaphragm
Lung cancer signs?
Look out for lymphadenopathy-hilar/mediastinal
Pleural effusion
Bony mets
cardiac failure?
Insufficient cardiac output due to:
Failure of heart to pump adequately
High circulatory resistance
Fluid overload
Left ventricular failure is the most common
Results in ↓cardiac output and ↑pulmonary venous pressure
Right ventricular failure usually occurs due to longstanding LV failure or pulmonary disease
Causes ↑ systemic venous pressure → peripheral oedema
Heart failure signs?
Heart size
Pulmonary vessel & parenchymal changes
Pleural changes
heart size?
Cardiomegaly
Cardiothoracic ratio > 0.5-heart width over thoracic width
Must assess on a PA radiograph
Doesn’t always mean failure. DDx:
Pericardial effusion, cardiomyopathy, etc
Radiological features of HF?
Radiological features progress as pressures increase
Normal pulmonary capillary pressure 5-12 mmHg
12-17mmHg: Pulmonary vascular redistribution
17-20mmHg: Interstitial oedema
>25mmHg: Alveolar oedema & pleural effusion
Upper lobes diversion?
: erect film only – upper lobe vessels are smaller and fewer due to gravity. But pulm vascular bed has great reserve capacity. When pressure goes up, more vessels are recruited, opening up new and distending established vessels (more in the upper lobes) to pulmonary blood flow therefore blood RE-DISTRIBUTES to the upper lobes.
Kerly B?
They are perpendicular to the pleural surface and extend out to it. They represent thickened subpleural interlobular septa and are usually seen at the lung bases
interstitial oedema?
Upper lobe venous diversion PCP ~ 15mmHg
Kerley B lines ~ 15-20 mmHg
alveolar oedema?
Aveolar odema-Bat-wing &
pleural effusions > 25 mmHg
pneumothorax?
Important diagnosis- potential medical emergency
Air in pleural cavity, compresses underlying lung
Defect in parietal or visceral pleura
Aetiology:
Primary spontaneous
Secondary- emphysema, asthma, infection
Trauma- penetrating injury
Signs in Pneumothorax?
Erect chest radiograph:
Sharp white line of visceral pleura
No lung markings between this and chest wall
May see blunting of costophrenic angle – with small amount of pleural fluid
Do not confuse with skin fold – these extend beyond margin of lung fields and have lung markings beyond them
tension pneumothorax?
One way valve effect- air can enter pleural space but not leave
Rapid collapse of underlying lung and mediastinal shift
Imminent cardiovascular collapse- URGENT management
COPD ?
Hyperinflation Flattened diaphragm Eight anterior ribs visible Heart appears vertically oriented (‘stretched out’) Coarse bronchovascular markings- ‘dirty lungs’ Look for complications: Infection- consolidation Pneumothorax Lung cancer
measuring hemidiaphragm?
Hemi-medial to lateral and if less than 1.5 cm of diaphragm above
pulmonary embolism?
Thrombus in the pulmonary arteries
Has usually travelled (embolised) from deep venous thrombosis in legs or elsewhere
If large, can cause significant haemodynamic compromise
CT pulmonary angiogram performed for diagnosis- dedicated CT with IV contrast timed to assess the pulmonary arteries
CTPA considerations?
sig renal impairment ionising radiation preg and breastfeeding V/Q scan instead nuclear medicine test?
