Radiology Flashcards
Describe colours in X ray
- Bone has high attenuation so appears white
- Lungs appear black due to low attenuation
- Soft tissues appear grey
Describe colours in CT scan
- Bone has high attenuation so appears white
- Lungs black due to low attenuation
- Soft tissues appear in shades of grey
What is ground glass opacification?
- Air is not completely displaced
- Pattern telling you there is something displacing air in the airways or interstitium
- Could be haemorrhage, hypersensitivity pneumonitis
Compare consolidation and ground glass opacification
- When I see consolidation I say to myself that there is some pathology in the lungs which has COMPLETELY displaced (e.g. by infection, blood, tumour).
- When I see ground glass what I tell myself is that the air has been PARTIALLY displaced.
- It may be the same pathological processes
Describe appearance of consolidation
- Different density to the lungs (white)
- Ill defined, fluffy.
- Confluent
- Loss of vessel pattern
- Air bronchograms (dark bronchial outline that can be seen within the consolidation. Alveoli filled with material and bronchioles still gilling with air)
Describe appearance of nodule or mass
- Nodule less than 3mm
- Mass more than 3mm
- Round opaque lesions on X ray
Describe appearance of pneumothorax
- Visible visceral pleural edge is seen as a very thin, sharp white line
- No lung markings are seen peripheral to this line
peripheral space is radiolucent compared to the adjacent lung - Lung may completely collapse
- Mediastinum should not shift away from the pneumothorax unless a tension pneumothorax is present
- Subcutaneous emphysema and pneumomediastinum may also be present
Describe appearance of pleural effusion
- Very dense
- Meniscus (fluid line - as you get towards the wall of the lungs the level of the opacity increases)
- Density highest at the base and gradually less dense as you move up
- Obliteration of the hemidiaphragm and costo-phrenic angle
- Pulls trachea towards opposite side
Describe appearance of atelectasis
- Shifted mediastinum towards the collapsed side
- White out due to lack of air
- Lung volume loss
Describe the difference between haustra and valvulae conniventes
- Haustra are not complete, only partway through the lumen. Enlarged haustra suggest large bowel obstruction
- Valvulae conniventes are circular folds going the whole way through the bowel wall, suggest small bowel obstruction
Describe a cavitating lesion
- A lucent area contained within a consolidation, mass, or nodule
- Air fluid level
List causes of cavitating lung lesions
- Infection (TB, staph, klebsiella eg. alcoholics)
- Inflammation (RA)
- Infarction (PE)
- Malignancy
Compare CXR appearance of pulmonary fibrosis and pulmonary oedema
- Honey combing pulmonary fibrosis (course)
- Ground glass is pulmonary oedema (fine)
Describe AXR analysis
- Air
- Bowel
- Dense structures (bone, calcification)
- Organs and soft tissues
- X- eXternal organs and artifacts (eg. JJ tube goes from skin to kidney to bladder, nephrostomy tube connects this to the skin)
Define pneumoperitoneum
Air under the diaphragm, due to bowel perforation
Describe AXR appearance of IBD
Thumbprinting - thickened bowel wall
Describe AXR appearance of bowel obstruction
- Small bowel dilation look for valvulae conniventes, these go all the way from one side of bowel tot he other
- Large bowel look for haustra, which do not go all the way
- 3, 6, 9cm rule (small intestine, large intestine caecum respectably)
Describe AXR appearance of volvulus
- Coffee bean sign sigmoid volvulus
- Embryo sign caecal volvulus
- Friiman daal sign
- Liver overlap sign
