Interpreting CXR

Question 1

What framework would you use to assess image quality?

Answer 1

• Rotation
  
  • medial clavivles equidistant from spinous process
• Inspiration
  
  • 5-6 anterior ribs
  • lung apices
  • costophrenic angles
• Penetration
  
  • Assume PA if not labelled
• Exposure
  
  • L hemidiaphragm visible to spine
  • Vertebrae visible behind heart

Question 2

Briefly list down what key landmarks would you look for in the ABCDE approach

Answer 2

• Airway
  
  • trachea, carina, bronchi, hilar structure
• Breathing
  
  • lung, pleura
• Cardiac
  
  • heart size, borders
• Diaphragm
  
  • costophrenic angles
• Everything else
  
  • bones, valves, pacemakers

Question 3

What would you assess for Airways?

Answer 3

• Tracheal deviation
• Carina
  
  • If NG tube present > should disect carina
• R main bronchus
  
  • wider, shorter, more vertical
• L main bronchus
• Hilar structures
  
  • L higher than R

Question 4

What causes hilar enlargement?

Answer 4

• Bilateral - Sarcoidosis
• Unilateral - Malignancy

Question 5

What causes abnormal hilar positioning?

Answer 5

• Hilar being pushed
  
  • mass
• Hilar being pulled
  
  • lobar collapse

Question 6

What do you assess in breathing?

Answer 6

• Lungs
  
  • Divide into 3 zones
  • Compare zones between lungs
  • Lung markings
  • Infiltrations
  • Lesions
  • Reticular, nodular, reticonodular pattern
• Pleura
  
  • If visible > thickening > mesothelioma

Question 7

What will you assess for Cardiac?

Answer 7

• Heart size
  
  • Normal CT ratio: equal or <50% of thoracic width
  • only for PA
• Heart boarders
  
  • R A - makes up most of R border
  • L V - makes up most of L border

Question 8

What will you assess in Diaphragm?

Answer 8

• R hemidiaphragm higher than L
  
  • due to liver
• Pneumoperitoneum
• Pseudopneumoperitoneum
• Chilaiditi sign
• costophrenic angle

Question 9

What causes pneumoperitoneum?

Answer 9

• Perforated hollow viscus
  
  • PUD
  • ischaemic bowel
  • bowel obstruction
  • necrotising enterocolitis
  • appendicitis
  • diverticulitis
• Postoperative free intraperitoneal gas
• Pneumothorax

Question 10

What is pneumoperitoneum?

Answer 10

• gas within peritoneal cavity

Question 11

What is pseudopneumoperitoneum?

Answer 11

• Any gas within abdominal cavity that masquerades as free intraperitoneal gas when in fact contained within organ

Question 12

What causes pseudopneumoperitoneum?

Answer 12

• basal linear atelectasis
• pneumomediastinum
• Chilaiditi sign
• pseudo-Rigler sign
• diaphragmatic undulation
• gas within skin folds
• biliary, portal vein or bowel wall gas
• benign post-traumatic pseudopneumoperitoneum

Question 13

What is chilaiditi syndrome?

Answer 13

• abnormal position of the colon between the liver and the diaphragm resulting in the appearance of free gas under the diaphragm

Question 14

What will you look for in everything else?

Answer 14

• Mediastinal contours
  
  • Aortic knuckle
    
    • if reduced definition > aneurysm
  • Aorto pulmonary window
• Bones
  
  • lesions
  • fractures
• Soft tissue
• Tubes, valves, pacemaker