Differential diagnosis for a small cardiothoracic ratio

A small cardiothoracic ratio (CTR) as defined as <42%/0.42 when assessed on a PA chest radiograph, and can be due to number of entities:

A pathologically-small heart is known as microcardia and may be associated with small heart syndrome.

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Article information

rID: 9884
System: Chest, Cardiac
Section: Gamuts
Synonyms or Alternate Spellings:
  • Small cardiac silhouette
  • Reduced cardiothoracic ratio (CTR)
  • Low cardiothoracic ratio (CTR)
  • Decreased cardiothoracic ratio (CTR)
  • Small heart
  • Small CTR
  • Differential diagnosis for a small heart size
  • Small cardiothoracic ratio (CTR)
  • Microcardia

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