Dense vein sign
The dense vein sign refers to hyperattenuating thrombus within a cortical vein or dural venous sinus due to acute venous thrombosis.
When located in the superior sagittal sinus, particularly posteriorly, it is sometimes referred to as the delta, triangle or pseudodelta sign. It is really the same as the cord sign except the vessel is imaged in cross-section.
A potential pitfall is interpreting the distal superior sagittal sinus as being hyperdense near the torcula herophili; it is important to appreciate that normal blood within the dural sinuses is usually of slightly increased density relative to brain parenchyma and that true hyperdensity is the key to recognizing thrombosis. The walls at this location can be thick, measuring up to 2-3 mm.