Yin-yang sign

The yin-yang sign is a radiological sign described in both true and false aneurysms on various imaging modalities. 

Radiographic features

Doppler sonography

The yin-yang sign indicates bidirectional flow due to swirling of blood within the (true or false) aneurysm.

Contrast-enhanced CT

The patent portion of the lumen of the aneurysmal vessel demonstrates increased attenuation, due to contrast enhancement, whereas a part of the lumen shows reduced attenuation due to mural thrombus.

History and etymology

It is named after the symbol representing the Chinese philosophers' thoughts to describe how opposing forces are interconnected and interdependent. It has also been likened to the logo for Pepsi, the well-known cola beverage.

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Article information

rID: 17024
System: Vascular
Section: Signs
Tag: refs
Synonyms or Alternate Spellings:
  • The Yin-Yang sign
  • The Yin and Yang sign
  • Ying-yang sign
  • The ying-yang sign

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Cases and figures

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    Figure 1: diagram: the yin-yang sign
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    Case 1
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    Case 2
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    Case 3: on video
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    Case 4: the yin-yang sign on CT
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    Case 5
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    Case 6
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    Case 7
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