Systematic Approach to Interpreting Chest X-Rays

Learning Objectives

• Understand the systematic approach to interpreting chest x-rays.
• Learn the correlation between anatomy and normal shadows on the x-ray.

Importance of a Systematic Approach

• Crucial for clinicians with less experience in reading chest x-rays.
• Reduces the likelihood of missing important findings.
• Should include all aspects of chest x-ray interpretation.
• Elements should be examined in a logical sequence that is easy to remember.
• No one best system, but assessing the film's technical quality is essential.

The ABCDEF System

• A: Airways
• B: Bones and soft tissue
• C: Cardiac silhouette and mediastinum
• D: Diaphragm (including gastric air bubble assessment)
• E: Effusions (assessment of the pleura)
• F: Fields (lung fields)
• Additional: Assessment of lines, tubes, devices, and prior surgeries (e.g., sternotomies, valve replacements)

Advantages of the ABCDEF System

• Easy to remember.
• Examines lungs near the end to avoid distraction from potential lung abnormalities.

X-Ray Anatomy: A to F

Airways

• Structures visible: Trachea, right and left main bronchus.
• Note: The left main bronchus is more horizontal than the right, affecting the path of aspirated foreign bodies and endotracheal tube placement.

Bones

• Visible bones: Ribs, clavicle, sternum, vertebral bodies.
• Details:
  • Posterior rib: easier to see, oriented horizontally.
  • Anterior rib: harder to see, oriented at 45° angle.

Cardiac Silhouette and Mediastinum

• Anatomic structures forming silhouette:
  • Bumps, knobs, and sides (e.g., aortic arch, pulmonary artery).
  • Aortopulmonary window: houses the recurrent laryngeal nerve and lymph nodes.

Diaphragm and Pleura

• Diaphragm:
  • Right Hemi diaphragm typically higher due to liver position.
  • No truly flat structures; diaphragms are curved.
• Pleura:
  • Normally invisible, but crucial for diagnosing pneumothorax, pleural plaques, thickening.
  • Costophrenic angles: spaces where diaphragm meets thoracic wall.
  • Gastric air bubble typically seen under left Hemi diaphragm.

Lung Fields

• Fissures:
  • Horizontal fissure on the right, visible on PA view.
  • Right and left oblique fissures not usually visible.
• Lobes:
  • Right lung: three lobes (upper, middle, lower)
  • Left lung: two lobes (upper, lower)
  • Lower lobes extend to near the apex of the lung.

Conclusion

• Systematic approach helps in comprehensive evaluation.
• Next video will cover chest film's technical quality assessment.