Main renal arteries
Assessment of the right and left renal arteries from their origins where technically visualised.
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Book renal artery Doppler — £249
Book RAS Doppler — £249
Private vascular Doppler • London & St Albans
Private Renal Artery Stenosis Doppler Scan
A specialist duplex ultrasound assessment of the arteries supplying both kidneys, designed to evaluate blood-flow velocities and Doppler patterns for signs of renal artery narrowing (stenosis) — a recognised cause of secondary hypertension and impaired kidney function.
- No GP referral required
- Duplex colour & spectral Doppler
- Both kidneys assessed
- Written diagnostic report
PrivateSono price£249Renal artery Doppler scan
Renal duplexColour + spectral Doppler
30–45 minTypical scan duration
No radiationUltrasound only
Self-referralBook directly
Quick answer
What is a renal artery stenosis Doppler scan?
A renal artery Doppler ultrasound, also called a renal duplex or RAS scan, evaluates the blood vessels that carry blood from the aorta to the kidneys. The test combines real-time ultrasound imaging with Doppler measurements of blood-flow velocity and waveform shape.
It is commonly used when renal artery stenosis is suspected because of difficult-to-control hypertension, an unexplained deterioration in kidney function, asymmetric kidney size or established vascular disease. The examination can support diagnosis, but some patients require CT angiography, MR angiography or specialist review for confirmation or treatment planning.
What the scan checks
Renal arteries, kidney perfusion and Doppler measurements
The examination is designed to assess both structural and haemodynamic features of the renal circulation.
Peak systolic velocity
Spectral Doppler measures blood-flow velocities that may rise where a vessel is significantly narrowed.
Renal-aortic relationship
Renal artery measurements may be interpreted in relation to aortic flow as part of a full duplex assessment.
Intrarenal waveforms
Segmental or interlobar arterial waveforms can show downstream changes associated with proximal arterial disease.
Kidney size & symmetry
Both kidneys are measured and compared for asymmetry or chronic structural change visible on ultrasound.
Colour-flow patterns
Colour Doppler helps demonstrate vessel course, flow direction and areas of turbulence where visible.
Important: renal artery Doppler can be technically challenging. Bowel gas, body habitus and deep vessel position can limit visualisation. A technically limited examination does not exclude renal artery disease.
When it may help
Common reasons to book a renal artery Doppler
- High blood pressure that remains difficult to control despite treatment
- Sudden or unexplained worsening of previously stable hypertension
- Hypertension developing at an unusually young age
- Unexplained deterioration in kidney function blood tests
- Known atherosclerosis or peripheral arterial disease
- Kidney-size asymmetry on previous imaging
- Monitoring of previously identified renal artery narrowing
- Clinical concern about renovascular hypertension
Urgent symptoms: very high blood pressure accompanied by chest pain, severe breathlessness, neurological symptoms, confusion or collapse requires urgent medical assessment rather than waiting for a routine private scan.
How Doppler helps
What the vascular clinician measures
Renal artery stenosis is not diagnosed from one number alone. The vascular clinician combines vessel appearance, velocities, ratios and downstream waveforms.
| Measurement | What it assesses | Why it matters |
|---|---|---|
| Renal artery PSV | Peak systolic velocity in the renal artery | Markedly elevated velocity can support the presence of haemodynamically significant narrowing. |
| Renal-aortic ratio | Comparison of renal artery and aortic velocities | Helps standardise interpretation of elevated renal artery velocity. |
| Acceleration / waveform | Shape and systolic upstroke of intrarenal arterial flow | Delayed or damped downstream waveforms can support proximal arterial disease. |
| Resistive index | Intrarenal vascular resistance | Provides additional information about renal parenchymal vascular resistance. |
| Kidney length | Size and side-to-side symmetry | Asymmetry can be relevant in chronic renovascular disease. |
Clinical interpretation matters: Doppler criteria depend on technique, vessel visibility, patient factors and the complete examination. The report should not be interpreted from an isolated velocity measurement.
Before you arrive
How to prepare for your renal artery Doppler
Fast for 6 hours
PrivateSono currently advises no food for at least six hours before the scan to help reduce bowel gas and improve visualisation of the renal arteries.
Drink clear still water
The current PrivateSono service instructions ask patients to drink approximately one litre of clear still water about one hour before the appointment.
Keep your bladder full
The current service instructions advise not emptying your bladder until after the examination. Follow the exact instructions in your booking confirmation.
Take usual medication
Continue prescribed medicines as usual unless your clinician has told you otherwise. If you have diabetes, follow the clinic’s individual fasting advice.
Your appointment
What happens during a RAS Doppler scan?
The examination commonly takes around 30–45 minutes, depending on anatomy and technical visibility.
- 1
Clinical review
Your vascular clinician reviews your blood-pressure history, medication, kidney function, previous imaging and relevant vascular risk factors.
- 2
Kidney and aortic imaging
You lie on the examination couch while ultrasound gel and a probe are used over the abdomen and flanks. The kidneys and relevant abdominal vascular landmarks are assessed.
- 3
Renal artery Doppler
Colour and spectral Doppler are used to record blood-flow velocities and waveforms from the renal arteries and intrarenal circulation where visualised.
- 4
Breathing and position changes
You may be asked to hold your breath, turn onto your side or alter your position to improve views of deep abdominal vessels.
- 5
Report and recommendations
Key findings are explained and documented in a written report, with GP, renal, hypertension, vascular or further imaging follow-up advised when appropriate.
Choosing the right test
Ultrasound, CT angiography or MR angiography?
Renal artery Doppler is non-invasive and radiation-free, but not every renal artery can be fully visualised by ultrasound.
Duplex ultrasound
Useful first-line assessment of blood flow without radiation or contrast injection.
CT angiography
Can provide detailed arterial anatomy when ultrasound is limited or intervention planning is required, but uses ionising radiation and iodinated contrast.
MR angiography
May provide cross-sectional vascular assessment without ionising radiation, depending on clinical circumstances and local protocol.
Clinical review
Blood pressure pattern, kidney function, medication and overall vascular risk determine whether imaging findings are clinically significant.
Book online
Book your renal artery stenosis Doppler scan
Book directly with PrivateSono using the dedicated renal artery Doppler service.
- Both renal arteries assessed where technically visualised
- Kidney size and intrarenal Doppler waveforms
- Colour and spectral Doppler measurements
- No ionising radiation
- Written diagnostic report
Need help choosing the correct vascular scan?
Call 020 7101 3377
Open secure booking — £249
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Why choose PrivateSono?
Focused renal vascular assessment with clear reporting
A targeted duplex examination for patients with suspected renovascular hypertension, kidney-function concerns or known arterial disease.
Check appointmentsDuplex Doppler
Combines structural ultrasound with colour and spectral blood-flow assessment.
Both kidneys
Kidney size and bilateral renal arterial circulation are assessed where technically possible.
No radiation
Ultrasound uses sound waves and does not require ionising radiation.
Onward guidance
The report can support GP, nephrology, hypertension or vascular review if abnormalities are found.
Clinic locations
Private renal artery Doppler in London and St Albans
Choose your preferred clinic and appointment when booking online.
Central London
27 Welbeck Street
London W1G 8EN
Near Harley Street and Marylebone.
St Albans
54–56 Victoria Street
St Albans AL1 3HZ
Convenient for Hertfordshire and North London.
Questions & answers
Renal artery Doppler FAQs
Direct answers for patients and search assistants.
Book RAS Doppler →What is a renal artery Doppler scan? +
A renal artery Doppler ultrasound is a non-invasive duplex scan that assesses the arteries supplying the kidneys. It combines standard ultrasound with colour and spectral Doppler to evaluate renal artery anatomy, blood-flow direction, velocities and waveform patterns.
What can a renal artery stenosis Doppler scan detect? +
The scan can identify Doppler features that may suggest narrowing of one or both renal arteries, reduced or turbulent blood flow, asymmetry between the kidneys and abnormal intrarenal waveforms. Results are interpreted in the context of the complete examination and your clinical history.
Why might I need this scan for high blood pressure? +
Renal artery stenosis is one recognised cause of secondary hypertension. A renal artery Doppler may be considered when blood pressure is difficult to control, rises unexpectedly, develops at a young age, or is accompanied by changes in kidney function.
Does the scan assess both kidneys and both renal arteries? +
Yes. The examination is designed to assess both kidneys and the renal arterial circulation where technically visualised, including colour and spectral Doppler measurements and intrarenal waveforms.
How should I prepare for a renal artery Doppler scan? +
PrivateSono currently advises fasting for at least six hours before the appointment. The service page also asks patients to drink about one litre of clear still water one hour before the scan and not empty the bladder until after the examination. Take usual medication unless advised otherwise, and follow your booking confirmation if it differs.
How long does a renal artery Doppler scan take? +
A renal artery Doppler commonly takes around 30 to 45 minutes, although the examination may take longer if the arteries are difficult to visualise or additional measurements are required.
Is renal artery Doppler ultrasound painful or harmful? +
The scan is non-invasive and uses sound waves rather than ionising radiation. Most people find it comfortable, although firm probe pressure may occasionally be required to obtain views through the abdomen.
Can ultrasound always see the renal arteries? +
Not always. Bowel gas, body habitus, breathing pattern, vessel depth and arterial anatomy can limit visualisation. If the study is technically limited or findings remain uncertain, CT angiography, MR angiography or specialist review may be recommended.
What happens if renal artery stenosis is suspected? +
The report documents the Doppler findings and may recommend review by your GP, nephrologist, hypertension specialist or vascular team. Additional blood tests or cross-sectional angiographic imaging may be needed depending on the severity and clinical context.
How much is the PrivateSono renal artery stenosis Doppler scan? +
The current PrivateSono renal artery stenosis Doppler service page lists the scan at £249. Check the booking page for the latest price and appointment availability before payment.
Renal artery stenosis Doppler
Assess kidney arterial blood flow without radiation
Book directly with PrivateSono in Central London or St Albans.