T2 L14: Imaging techniques and diseases of lung

• What is a normal cardiothoracic ratio? (C/T)

  <0.5
• What are the strengths and weaknesses of X-RAY?

  Strengths:

  • Great spatial resolution - especially bone
  • Cheap & available
  • Easy interpretation

  Weaknesses:

  • Projectional Ionising radiation
  • Very limited soft tissue visualisation
• What are the strengths and weaknesses of CT?

  Strengths:

  • Cross-sectional
  • Spatial resolution
  • Widely available

  Weaknesses:

  • Ionising radiation
  • Limited soft tissue contrast
• What is this image?

  scout view

  taken at the beginning of a CT

  dotted lines show every single slice taken

  
• What are the different thickness techniques in CT imaging?

  Thin sections (1mm) - more detailed, optimal for demonstrating lung, eg pleural disease

  Thick sections (5mm) - less detailed, shows more of thorax, optimal for detecting masses / tumour

  
• Highly vascular structures will be more enhanced than less vascular structures due to the higher amount of enhancing medium going in, and hence will appear brighter.
• What is the structure labelled 1 in this image?

  superior vena cava (brightest - first contact with contrast)

  the order of structures the contrast has been in can be determined via brightness.

  
• What does this image show?

  right upper lobe collapse

  
• What is the functional unit of the lung?

  secondary pulmonary lobule

  surrounded by connective tissue (septa)

  5-20mm in diameter

  
• What is this image showing?

  secondary pulmonary lobule (functional unit of lung)

  
• What does this image show?

  interstitial lung disease

  
• How can we obtain a picture of the distribution of ventilation in the lungs?

  nuclear medicine

  breathe in radioactive gas

  shows distribution of radioisotope throughout airways

  every black dot = radioactive decay

  
• How could we produce a steady state image of lung blood flow?

  isotope injected into veins
• What patient posture would achieve the most uniform distribution of particles throughout the lungs?

  lying flat on back
• What is the pathology shown in this X-ray?

  pleural effusion

  (fluid accumulation)

  blunts costaphrenic angle

  
• What is the pathology shown in this X-ray?

  symptoms: high temperature and cough

  infection

  lung full of fluid and pus

  
• What is 'consolidation' ?

  air space shadowing (white)

  fluid within small airways

  
• What is the pathology shown in this X-ray image?

  smoke inhalation from fire plus pulmonary oedema

  
• Is this shadow at the front or at the back?

  front

  right heart border can't be seen

  right heart border is at the front

  
• Is this shadow at the front or at the back?

  back

  right heart border visible

  
• What is the pathology shown?

  TB

  'sand scattered evenly throughout lung'

  
• What is the pathology marked by the red cross?

  pulmonary embolism

  
• What is a 'mismatched defect'?

  normal ventilation but abnormal perfusion
• What is the name of the blood vessel labelled A?

  left subclavian artery

  
• What kind of imaging technique is this and what is it showing?

  Venogram

  veins

  white 'blobs' are valves