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
- 1. Pappas JN. The angiographic string sign. Radiology 2002; 222(1):237-8. PubMed