Two studies, two questions
Veins fail in two ways, and the ultrasound that looks for one is not the ultrasound that looks for the other. We do both, and which one you need depends entirely on the question.
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Venous duplex for clot (DVT). The technologist presses the probe down over each vein along its length. A normal vein flattens completely under pressure. A vein with clot in it does not. This is the study ordered for a suddenly swollen, painful calf. DVT & Pulmonary Embolism →
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Venous reflux study. Performed standing, or on a tilted table, because gravity is the whole point. Valves inside the leg veins are supposed to keep blood moving upward. When they leak, blood falls backward and pressure builds in the leg. The study measures how long that backward flow lasts. This is the study for aching, swelling, varicose veins, and skin damage at the ankle. Superficial Venous Disease →
Why it matters
Ultrasound is excellent at the veins that matter most and measurably weaker below the knee. Knowing where it is strong is part of using it well.
What the clot study looks for
A deep vein clot matters for two reasons. It can break loose and travel to the lung. Even when it does not, it can damage the vein’s valves permanently, leaving a leg that swells and aches for years afterward.
The study also tells us where the clot is, which changes what happens next. A clot confined to the calf is managed differently from one filling the femoral or iliac vein. Clots at the iliac level are about two and a half times more common on the left than the right — a fingerprint of the artery crossing over and compressing the left iliac vein against the spine. Iliac Vein Compression →
What the reflux study looks for
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Superficial veins. The great and small saphenous veins and their tributaries — the usual source of varicose veins.
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Deep veins. Whether the deep system is patent and whether its valves hold.
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Perforating veins. The connections between the two systems, which can leak in either direction.
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Obstruction, not just leakage. Reflux is only half the story. A vein squeezed shut upstream raises pressure just as effectively as a leaking valve, and it is routinely missed. If the picture does not add up, we look at the iliac veins with ultrasound from the inside.
The distinction is not academic. Treating leaking valves in a leg whose real problem is an obstructed iliac vein does not fix the leg. Venous Ulcers →
When to call 911, and when to call us
A clot in the leg can travel to the lung, and that is an emergency.
Call 911 right away if you have any of these:
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Sudden shortness of breath, chest pain that worsens with a deep breath, or coughing up blood
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A rapid heartbeat with lightheadedness alongside a swollen leg
These can mean a clot has traveled to the lung. Do not drive yourself and do not call our office first.
Call our office today if you notice:
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Sudden swelling of one leg, with pain, warmth, or redness in the calf or thigh
Call our office at (918) 943-5303 and tell us what’s changed — we’ll get you seen sooner, because catching these early often keeps a small problem from becoming a big one.
For referring providers — We perform venous duplex for clot and standing reflux studies in our office, and can work in a suspected acute DVT the same day. Refer: (918) 943-5303 · fax (855) 312-3594.
Refer urgently: a suspected acute DVT, a swollen and painful limb, or any suspicion of pulmonary embolism · Routinely: varicose veins, chronic leg swelling, skin changes or a healed ulcer at the ankle, or a leg that swells out of proportion to its varicosities. Full referral guide →