Ultrasound guided sclerotherapy is used to treat moderate to severe vein disease of the lower extremities. It treats symptoms of venous insufficiency by closing malfunctioning veins from the inside.

During USGS:

One of our specialized interventional radiologists uses an ultrasound to map the diseased veins and plan your treatment.
Next, they will inject a sclerosant solution into the affected veins.
This solution prompts the vessel’s blood to thicken and its walls to purposely become irritated.
As a result, the vein collapses and becomes sealed off from blood flow.
The collapsed vein’s blood flow is then diverted to your healthy, surrounding veins.
Over time, the diseased vein is naturally absorbed into the body, so there is no
need to remove it.