Thoracic Imaging 2/3 Flashcards
Explain the use of the different imaging modalities for the thorax
- Radiography
- Important
- Main imaging tool for thorax
- US
- Important for heart
- Emergency US very useful.
- Compliments radiography.
- CT
- Use where radiograph and US fail to identifiy cause and extent of disease
- Modality of choice for lungs
- Endoscopy
- Useful for larger airways and oesophagus
- MRI
- Fewer indications
- Not used too much
Explain the mass effect
- Displacement of structures due to adjacent space-occupying lesions e.g. mass or fluid.
- A mass will displace normal structures away from itself.
Explain mediastinal shift
- In VD/DV views - you have displacement of the midline structures due to increased or decreased volume of adjacent structure e.g. mass, fluid or lung collapse.
Common pleural fluid patterns
Patterns are useful for differentials. Normally, fluid will flow freely through the left and right side as medistinum is leaky. If thick fluid, you will get predominatly unilateral appearance. if have abdo fluid too - systemic disease. If lots of elevation of trachea, caudal displacement of the heart - think things that could cause masses.
- Unilateral, encapsulated, large effusion: pyothorax
- Concurrent abdo fluid with small effusion = hypoproteinaemia, FIP, heart failure
- Trachea elevated and compressed, heart caudally displaced with large effusion = lymphoma, thymoma
- Large effusion = chylothorax
- Trauma signs = blood, lymph
What pattern?
Bronchial markings in a dog - can see donuts and tram lines
Common bronchial patterns in dogs?
- Mild pattern in old animals = ageing change
- Thick soft tissue cuffs = oedema, pneumonia, eosinophilic bronchopneumopathy
- Thin soft tissue cuffs = chronic bronchitis
- Very thin, mineral opacity cuffs = HAC
- Wavy tramlines = bronchiectasis
what pattern
Alveolar
- Fuffy increased opacity
- Border obliteration
- Air bronchograms
Common alveolar patterns of dogs?
- Ventral = pneumonia
- Symmetrical perihilar ( in central 3rd) = cardiogenic oedema
- Caudodorsal = non cardiogenic oedema
- Peripheral = angiostrongylus, thromboembolism
- Unilateral, middle/cranial lobe = collapse
Location of normal vasculature in lateral and DV views?
- Normal pulmonary vessels are clearly visible in central and middle zones
- Vessels taper towards the periphery
- In lateral views
- Artery is dorsal to bronchus and vein
- Veins are ventral to bronchus and vein
- DV
- Veins are medial to arteries
- VEINS ARE VENTRAL AND CENTRAL
Explain types of interstitial pattern
Interstitium is a small volume of the lung that binds all of this together. If affected, get this pattern. Two main types:
- Diffuse
- Nodular
Explain diffuse interstitial pattern
Something happens to increase the volume of that area within the lungs e.g. fibrosis, cellular infiltration, fluid within the area. The interstitium is very small part of volume of lung, so increased opacity will be modest cf. alveolar disease.
What pattern?
Intersitial - Diffuse
What pattern?
Intersitial - nodular
Causes for different interstitial patterns?
- Solitary nodule (>5mm) (Not necessarily cancer! Can be lots of things)
- Indistinct (see with inflammatory diseases, as they tend to spread outside the focus of the disease)
- Focal pneumonia
- Granuloma/abscess
- Haemorrhage/contusion
- Infarct/thromboembolism
- Fluid filled bulla/cyst
- Well circumscribed
- Neoplasia(primary or secondary)
- cyst
- (abscess/granuloma)
- Indistinct (see with inflammatory diseases, as they tend to spread outside the focus of the disease)
- Evenly rounded, discrete multiple nodules
- Metastatic neoplasia
- Primary lung tumours
- Miliary nodulation (2-5mm)
- Metastatic neoplasia
- Granulomatous eosinophilic bronchopneumopathy
- Aelurostrongylus (cat)
- TB
- Unstructured
- Ageing changes
- Fibrous healing or chronic disease
- Early/late oedema, haemorrhage, pneumonia
- (Pneumonitis, diffuse metastasis e.g. lymphoma)
What species and why?
- Cat
- Recess from caudal T11
