The clot meniscus sign, or simply the meniscus sign, is a radiological sign appreciated on digital subtraction angiography in the setting of endovascular clot retrieval for acute ischemic stroke caused by large vessel occlusion.
The sign describes the angiographic appearance of the proximal occluded site whereby it has a meniscoid or concaved appearance towards the proximal lumen 1-4. The claw sign is a variant of the clot meniscus sign, and specifically describes when the length of protruding contrast on either side of the meniscus is greater than half the diameter of the parent vessel 5.
The clot meniscus and claw signs may have clinical implications:
in both anterior and posterior circulation large vessel occlusion acute ischemic stroke, patients with a positive clot meniscus sign may be more amenable to contact aspiration (cf. stent retriever) as the method for endovascular clot retrieval 1,3
in posterior circulation large vessel occlusion acute ischemic stroke, presence of the clot meniscus sign may be associated with better angiographic outcome 2
in anterior circulation large vessel occlusion acute ischemic stroke, presence of the clot meniscus sign has no bearing on outcomes 4
in both anterior and posterior circulation large vessel occlusion acute ischemic stroke, presence of a positive claw sign may be associated with better angiographic outcome 5