Vascular Ultrasound and Duplex Scans in Singapore

Vascular ultrasound uses sound waves to examine blood vessels. Duplex ultrasound combines a picture of the vessel with Doppler information about blood flow. It is a diagnostic and monitoring test, not a treatment that removes plaque or dissolves a clot. The scan should answer a specific clinical question, with the result considered alongside symptoms, examination and other tests.

Your scan is performed and reported at Andrew Choong Vascular Surgery, Mount Elizabeth Novena Specialist Centre, Singapore; to book, WhatsApp the clinic or call +65 9376 8688.

For non-emergency assessment or review of an existing scan report, ask the clinic about the appropriate appointment. Bring any available referral and previous results; the records checklist explains how to prepare for your consultation.

For available examinations and advice on choosing between screening, a symptom-led scan and follow-up, see our vascular screening and vascular-lab services.

Why might a vascular ultrasound be requested?

A scan may help locate a narrowing, investigate a suspected clot, assess leaking vein valves, measure an abdominal aneurysm or monitor a previous repair. The examination depends on the question: a scan for DVT is different from a reflux study for varicose veins. Read or watch Dr Choong's introduction to duplex ultrasound.

Watch the short video: What Is a Duplex Ultrasound?

What are the main types of vascular scan?

What does an arterial duplex scan assess?

Arterial duplex examines blood flowing towards a limb or organ. In PAD, it can help identify the location and significance of a narrowing and check a bypass or treated artery. It may be combined with ankle or toe-pressure tests. These tests answer related but different questions, particularly when diabetes or kidney disease makes ankle measurements difficult to interpret.

How do DVT and vein-reflux scans differ?

A venous scan for suspected DVT assesses the veins for clot using compression and blood-flow information. A reflux study looks at whether valves allow blood to flow backwards, helping plan treatment for varicose veins. Position changes or gentle manoeuvres may be used. The exact protocol is chosen for the suspected problem, not as a universal scan for every swollen leg.

Can ultrasound assess an aortic aneurysm?

Abdominal ultrasound can measure the abdominal aorta for appropriate screening or surveillance. It does not show every part of the aorta equally well and is not a universal test to exclude acute dissection. Aortic assessment may instead require CT, MR or other imaging depending on the location and urgency.

What does a carotid scan show?

A scan of the neck can assess plaque and flow in the carotid arteries. The reported degree of narrowing must be interpreted with symptoms and the measurement method. Further imaging may be needed before a treatment decision. A carotid ultrasound does not assess every possible cause of stroke; see the carotid disease guide.

How is ultrasound used for dialysis access?

Mapping can help assess vessels before fistula or graft creation. It can also investigate an access that is developing poorly or has changed function. Findings must be combined with dialysis performance and examination. The dialysis access guide explains when symptoms need urgent attention.

Who can book a vascular ultrasound, and how?

You do not need a referral to book a vascular ultrasound with Dr Andrew Choong. Patients in Singapore can contact the clinic directly to arrange a scan for leg swelling, suspected varicose veins, a family history of aneurysm or a previous vascular problem that needs checking. Some Integrated Shield and corporate plans ask for a GP or specialist referral letter before they will reimburse a specialist visit, so if you intend to claim, check your policy or ask the clinic team before the appointment.

Three ways a scan is arranged

• Consultation with scan. The usual route. Dr Choong assesses your symptoms, the appropriate duplex scan is performed, and the result is discussed with you at the same visit wherever the schedule allows, so you leave with a diagnosis and a plan rather than a report to decode at home. This is the route for varicose veins, leg swelling, suspected arterial disease and aneurysm surveillance.
• Scan-only referral from your GP or another specialist. Referring doctors can request a specific examination, for example a lower-limb venous duplex for suspected DVT, a venous reflux study, an arterial duplex with ankle pressures, an aortic surveillance measurement or a carotid duplex. A written report goes back to the referring doctor, who keeps charge of your care; the clinic will indicate whether a specialist opinion is also advisable.
• Follow-up and surveillance scans. Patients who have had varicose vein treatment, a stent or bypass, or an aortic repair return for scheduled scans at intervals set by the diagnosis. Aortic stent surveillance explains the aortic programme, including for patients whose original repair was done elsewhere.

Who performs and reports the scan?

Scans arranged through the clinic are performed in a vascular laboratory at the hospital or in the clinic, by Dr Choong or by a vascular sonographer working to a protocol chosen for your clinical question. Dr Choong reviews the images and the measurements himself and writes the report, which is why the result can usually be discussed on the day rather than at a separate appointment. If the scan raises a question that needs CT, MRI or another test, that is explained at the same time.

How quickly can a scan be done?

Routine scans are usually available within a few working days; a suspected DVT or an acutely painful, cold limb is handled the same day or directed to emergency care, depending on the symptoms. Contact the clinic for the next available slot. For what to bring, see the records checklist.

What happens during the examination?

A probe is moved over gel on the skin while images and flow measurements are recorded. You may be asked to turn, stand or adjust your position. Gentle pressure can be uncomfortable over a tender area; tell the person performing the scan if you are in pain. Standard external duplex scanning does not use ionising radiation and usually does not require injected contrast.

Preparation depends on the vessels being examined. An abdominal scan may require fasting, while other scans need little preparation. Follow the instructions supplied for your examination rather than fasting or changing medicines on your own. Bring previous results so that meaningful comparisons can be made.

Can ultrasound miss a problem?

Image quality can be limited by vessel depth, bowel gas, calcification, swelling or the ability to position the area. Small vessels and some deep segments are harder to assess. Results depend on a suitable protocol and experienced interpretation. A limited or normal scan does not automatically explain continuing symptoms or rule out every vascular condition.

Depending on the clinical question, the next step may be repeat imaging, another test or observation with a clear review plan. A suspected clot or acute artery problem needs a clinical pathway rather than reassurance based on a scan considered in isolation.

How do results guide treatment?

Ask what the result means for your symptoms, whether more information is needed and when review is due. An abnormality does not automatically require surgery. Medicines, monitoring, lifestyle measures or a procedure may be appropriate. Scan first, treatment second illustrates this approach to vein care.

When should I seek help instead of waiting for a scan?

New one-sided leg swelling and pain needs prompt medical assessment. Call 995 in Singapore for sudden breathlessness or chest pain, stroke symptoms, collapse, or a suddenly cold, painful and weak limb. Do not wait for a routine ultrasound appointment when emergency symptoms develop.

How can I discuss the right investigation?

For non-emergency symptoms or review of an existing report, contact Dr Andrew Choong's clinic at Mount Elizabeth Novena Specialist Centre, Singapore. An assessment can clarify which investigation is appropriate and how its result may change care. Scan arrangements and preparation depend on the examination requested.