String sign (artery)

The angiographic string sign, also known as the carotid string sign, refers to the thin string of intravenous contrast material distal to a stenotic focus in the internal carotid artery (ICA). 


A thin stripe of flow is caused by decreased pressure and flow distal to the stenosis, which causes a collapse of the distal ICA.


An angiographic string sign may be caused by:

  • pre-occlusive atherosclerosis at the carotid bifurcation
  • ICA dissection
  • ICA thrombosis
    • subacute partial
    • chronic subtotal
  • partial recanalization of an occluded ICA
  • stenosis secondary to radiation
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Article information

rID: 898
System: Vascular
Section: Signs
Synonyms or Alternate Spellings:
  • Carotid string sign

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Cases and figures

  • Case 1: ICA string sign
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