Why might I need a DVT ultrasound?
Your GP or specialist may request a DVT ultrasound if you develop symptoms that could suggest a blood clot in the leg.
Symptoms may include:
- new or unexplained swelling in one leg
- calf or thigh pain or tenderness
- redness or discolouration of the skin
- warmth in the affected leg
- more prominent surface veins
- unexplained leg discomfort, particularly when risk factors for DVT are present.
Your risk of DVT may be increased after:
- recent surgery or hospitalisation
- a period of reduced mobility or bed rest
- a long journey involving prolonged sitting
- injury or immobilisation of the leg
- a previous DVT or pulmonary embolism
- certain medical conditions or medications
- a personal or family history of blood-clotting disorders.
A DVT can occasionally occur without obvious symptoms.
If you develop sudden shortness of breath, chest pain, coughing up blood, fainting or severe difficulty breathing, seek urgent medical attention and call 000.
What does a DVT ultrasound assess?
A DVT ultrasound examines the deep veins of the leg for evidence of a thrombus, or blood clot.
Depending on the clinical indication, the sonographer may assess the:
- common femoral vein
- femoral vein
- popliteal vein
- posterior tibial veins
- peroneal veins
- soleal veins
- gastrocnemius veins.
The sonographer uses B-mode, colour Doppler and pulsed-wave Doppler ultrasound together with vein compression techniques to assess the veins and blood flow.
Healthy veins normally compress when gentle pressure is applied with the ultrasound probe. A vein that does not compress normally may indicate the presence of a blood clot.
The examination helps identify the location and extent of a DVT and provides important information for your referring doctor when deciding on further management.
What happens during the test?
No special preparation is usually required.
Please arrive approximately 5 minutes before your appointment to allow time for any necessary paperwork.
You may need to remove trousers, a skirt or other clothing so the sonographer can examine the leg from the groin to the ankle. Underwear can remain on.
You will usually lie on an examination bed while the sonographer applies ultrasound gel to the leg.
The ultrasound probe is moved along the leg and gentle pressure is applied at different points to check whether the veins compress normally.
The examination usually takes approximately 10–20 minutes per leg, although the time may vary depending on the findings and the extent of the examination.
How will I receive my results?
Following the examination, the ultrasound images and measurements are reviewed and a report is prepared.
The report will be sent to your referring GP or specialist, who can discuss the findings with you and advise whether any further assessment or treatment is required.
If the ultrasound identifies a DVT or another finding that requires urgent medical attention, the vascular team will communicate this promptly to the referring doctor and arrange appropriate next steps.
