Doppler ultrasound evaluates blood flow and can help assess clots, narrowing, aneurysms, venous reflux and organ perfusion.
What is Doppler ultrasound?
Doppler is an ultrasound technique that measures movement of blood. It can display the direction and speed of flow using colour images, waveforms and sound. A vascular ultrasound combines this information with images of the blood-vessel walls and surrounding tissues.
Why may it be requested?
- To look for deep vein thrombosis in the arms or legs.
- To assess arterial narrowing, plaque or reduced blood supply.
- To evaluate carotid arteries, the aorta, renal vessels or limb vessels.
- To assess varicose veins and venous reflux.
- To review a bypass graft, stent, dialysis fistula or previous vascular procedure.
- To investigate selected vascular compression syndromes or organ blood flow.
Preparation and scan experience
Many vascular scans need no special preparation. MBR Health currently advises fasting for Doppler, aortic and renal vascular studies because bowel gas can obscure deeper vessels. Follow the instructions supplied for your examination.
The sonographer applies gel and presses the probe over the vessel. Blood-pressure cuffs or gentle compression may be used. You may hear pulsing sounds while flow is measured. Detailed vascular examinations can take longer than a routine ultrasound.
What are the limitations?
Deep vessels, small vessels and vessels obscured by bowel gas, calcification or body habitus can be difficult to assess. Ultrasound also examines a defined region rather than the entire circulation. CT angiography, MR angiography, venography or catheter angiography may be needed for deeper anatomy, treatment planning or when ultrasound is inconclusive.
Vascular pathology can be complex. A normal scan of one vessel or position does not necessarily exclude disease elsewhere or a condition that occurs only under specific physiological circumstances.
Urgent symptoms
Ultrasound is a diagnostic test, not an emergency service. Sudden chest pain, severe shortness of breath, stroke symptoms, a cold or pulseless limb, or rapidly increasing swelling require urgent medical assessment.
Related Patient Guides
- PG3001 Ultrasound Scan: What to Expect Before, During and After Your Appointment
- PG3002 Preparing for an Ultrasound: Fasting, a Full Bladder and Other Instructions
- PG3003 Musculoskeletal Ultrasound: Dynamic Tendon, Ligament, Nerve and Joint Assessment
- PG3005 Pelvic and Transvaginal Ultrasound: What to Expect
- PG3006 Breast and Axillary Ultrasound: Lumps, Symptoms and Follow-Up
- PG3007 Thyroid and Neck Ultrasound: Nodules, Lymph Nodes and Biopsy
- PG3008 Paediatric Ultrasound: A Guide for Parents and Carers
- PG3009 Contrast-Enhanced Ultrasound and Elastography: Advanced Ultrasound Explained
- PG3010 What Ultrasound Can and Cannot Show: When MRI, CT or Other Tests May Be Needed
We have more detailed information on many interesting regenerative and radiological topics on our Insights page
Frequently Asked Questions
For other FAQs please visit our FAQs page
Does Doppler ultrasound use radiation?
No. It uses sound waves to assess anatomy and blood flow.
Will the probe pressure be uncomfortable?
Compression may be required, especially during a DVT assessment. It can be uncomfortable over a tender area but should be brief. Tell the sonographer if the pain is severe.
Why might I still need CT or MRI angiography?
Ultrasound is excellent for many accessible vessels, but deeper or complex vascular anatomy may require cross-sectional imaging for a confident diagnosis or treatment plan.
| Important: Seek urgent medical care for symptoms of stroke, pulmonary embolism, acute limb ischaemia or other vascular emergencies. |
PATIENT GUIDE • PG-3004 [Patient information: Doppler ultrasound evaluates blood flow and can help assess clots, narrowing, aneurysms, venous reflux and organ perfusion.]
