What it means
Blood normally flows freely and clots only to seal a wound. A thrombus forms when blood clots inside a vessel, for example when it flows slowly, the vessel wall is damaged, or the blood clots too easily. On ultrasound, a vein with a clot does not squeeze flat when the probe presses on it. On CT with contrast, a clot shows as a dark gap in a bright vessel.
When it matters
A clot in a deep leg vein (DVT) is usually treated with blood thinners. This helps stop a piece from breaking off and traveling to the lungs (pulmonary embolism). Clots in surface veins are often less serious but may still be treated. Clots in arteries or the heart can block blood flow or cause a stroke. Reports may say whether a clot looks acute (new) or chronic (old), which can change how it is managed.
Questions to ask your doctor
- Is the clot in a deep or a surface vein, and how far does it extend?
- Does it look new or old, and does it block the vessel completely?
- How long will treatment last, and will I have a repeat ultrasound?
Read more: Deep Vein Thrombosis (DVT): What a Blood Clot in the Leg Means and When It's Serious
