Chest X-Ray: Basics

• Indications: broad (respiratory or cardiac disease, tube positioning, trauma) 

• Characteristics of a good chest x-ray (PIER): 
  • Projection (AP, PA, lateral, lateral decubitus): heart will appear bigger on AP,  but not by much, AP is better for intubated/sick patients, two views is KEY
  • Inspiration and ribs: do you see at least 8-9 posterior ribs (if too little inspiration, things can crowd and mimic abnormalities)
  • Exposure: can you see the spine through the heart (too much penetration makes things dark, too little makes things bright and fuzzy)
  • Rotation and clavicles: what is the relationship between the clavicles and thoracic spinous processes (patient rotated to their right will have their left clavicle appear closer to the spinous process)
  • Angle of patient: should be perpendicular, but x-ray beams may be angled upward (apical lordotic), which can make anterior structures look more superior (clavicles above first rib)

• Approach
  • Start every time with verifying patient information and imaging quality (PIER)/information 
  • Then execute your systematic approach for consistency 
  • Common approach is the tubes + ABCDEFGHI approach
  • First looks at tubes, lines, drains
  • A = airway, B= bones, C = cardiac, D = diaphragm, E = effusions/extra-thoracic tissues, F = fields, fissures, foreign bodies, G = great vessels, gastric bubble, H = hilum and mediastinum, I = impression
  • A/airway = follow the trachea down, is it midline
  • B/bones = follow outline of bones to look for fractures
  • C/cardiac = heart should be around or less than 50% diameter of chest
  • D/diaphragm = right hemi is slightly higher due to liver, are they flattened
  • E/effusions and extra-thoracic tissues = check costophrenic angles, lateral films, look for swelling, subcutaneous air
  • F/fields, fissures, and foreign bodies = check lung fields for opacities, masses, pneumothorax, vessel markings, look at major and minor fissures, assess any foreign bodies (wires)
  • G/great vessels and gastric bubble = follow path of aorta, pulmonary arteries and veins, gastric bubble under left hemidiaphragm
  • H/hilum and mediastinum = look for prominence (sarcoid), lymphadenopathy, masses, check for mediastinal widening (thymus can be normal in kids)
  • I/impression = overall conclusion or what is going on considering your findings 

References: Herring's Learning Radiology, Radiopaedia, Mandell's CORE Radiology