What is the most sensitive indicator that a vessel is thrombosed?

The most sensitive indicator that a vessel is thrombosed is the lack of vessel wall coaptation upon compression. This phenomenon occurs because thrombosis typically leads to a filling of the vessel lumen with a clot, preventing the normal compression and coaptation of the vessel walls during ultrasound examination. When a healthy vessel is compressed, the walls will come together fully, indicating that the vessel is patent. In contrast, a thrombosed vessel will not exhibit this coaptation because the thrombus occupying the lumen prevents the walls from closing in on each other.

While other indicators like a thickened vessel wall, changes in flow velocity, or variations in Doppler signal may suggest vessel pathology, they are not as definitive in confirming the presence of a thrombus as the inability to compress the vessel fully. Lack of coaptation directly reflects the physical blockage within the vessel, making it a highly specific and sensitive indicator of thrombosis.