Xray

Silhouette Sign

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Silhouette Sign

  • Findings
  1. Seen on XRay films
  2. Loss of normal border between structures
    1. Different radiodensities form border on XRay
  3. Appearance of normally invisible outline
    1. Alternatively, Silhouette Sign represents loss of normal border (e.g. RML Pneumonia obscures right heart border)
  • Interpretation
  1. New border (or loss of border) suggests infiltrates, fluids or air
  2. False Positives
    1. Poor film technique (poor penetration or alignment)
    2. Normal anatomic variants
  • Resources
  1. Silhouette Sign (Radiopaedia)
    1. https://radiopaedia.org/articles/silhouette-sign-x-ray?lang=us