Renal Artery and Kidnet Parenchymal (functional tissue of the kidney) Flow, Duplex Ultrasound


  • Newly onset hypertension
  • Hypertension refractory to medical management
  • A patient outside the normal range for hypertension
  • Abdominal bruit
  • As a screen prior to medical management with ant-hypertensive pharmaceuticals
  • Follow up CTA renal artery aneurysm
  • Abnormal renal function blood tests
  • Pre-operative and post-operative surgical revascularisation or transluminal angioplasty of the renal artery, with or without intravascular stenting

Contraindications and limitations:

  • Extreme abdominal girth
  • Excessive abdominal gas
  • Site trauma such as open wounds in the scanning area
  • Ventilated patients, shortness of breath or rapid breathing may make it difficult to obtain accurate Doppler recordings
  • Patients that cannot be adequately positioned.

Patient preparation:

  • 2 days prior to the ultrasound, it is advisable for the patient to refrain from eating fatty foods, fizzy drinks or any foods that create bowel irritability or gas.
  • On the day of the ultrasound, fast from food and water for a minimum of 6 hours, refrain from chewing gum and smoking. If medication is required, this can be taken with a small sip of water. WHY? Gas in the bowel creates acoustic shadowing, on ultrasound imaging. Any vessels that sit in this shadow will not be seen, therefore cannot be assessed.


What to wear:

Loose-fitting clothes, for example; elasticated skirt/pants/shorts and a loose-fitting top.

Ultrasound study technique:

Ultrasound is a non-invasive diagnostic study. The patient will lie on a bed, with the head of the bed slightly elevated for comfort. Ultrasound gel will be applied to the abdomen. An ultrasound probe will be run over the abdomen, close to the rib cage and xiphisternum (lower border of the chest plate and at the angle of the ribs). Occasionally the sonographer may need to apply pressure to the abdomen to improve visualisation of the arteries, plus ask the patient to hold their breath, periodically, to accurately assess the spectral Doppler waveform velocities. To examine the kidney parenchyma, the bed will be flattened. The patient will lie on their side, whilst the kidney is being examined. The arcuate arteries, at the border of the renal cortex and renal medulla (outer border of the kidney) are very small therefore, substantial, periodic “breath holding”, and patience will be required, to obtain accurate spectral Doppler waveform velocities, acceleration times and resistive indices. Images will be obtained, and the results documented on a worksheet.

Ultrasound study time:

45-60 minutes


A worksheet can be available, if requested. A formal written report will be available within 24 to 48 hours, following the ultrasound examination, Monday to Friday. If the ultrasound findings demonstrate pathology, which may require urgent attention, the referring Doctor will be notified ASAP following the completion of the ultrasound.