The angiographic string sign, also known as the carotid string sign or slim sign, refers to the thin string of intravascular contrast material distal to a stenotic focus in the internal carotid artery (ICA).
Pathology
A thin stripe of flow is caused by decreased pressure and flow distal to the stenosis, which causes a collapse of the distal ICA.
Aetiology
An angiographic string sign may be caused by:
pre-occlusive atherosclerosis at the carotid bifurcation
-
ICA thrombosis
subacute partial
chronic subtotal
partial recanalisation of an occluded ICA
stenosis secondary to radiation