Popliteal Artery Entrapment Syndrome (PAES) Ultrasound Sydney
A Popliteal Artery Entrapment Syndrome (PAES) ultrasound is a specialised dynamic vascular ultrasound used to assess blood flow through the popliteal artery and vein behind the knee, particularly during movements that may reproduce symptoms.
PAES can occur when the blood vessels behind the knee are compressed by surrounding muscles or other anatomical structures. It is seen particularly in younger, active people and athletes, including runners.
Vascular ultrasound examinations are bulk billed with a valid referral.
Why might I need a PAES ultrasound?
Your GP or specialist may request a PAES ultrasound if you experience symptoms during exercise that raise concern about compression of the popliteal artery.
Symptoms may include:
- calf pain, aching or cramping during exercise
- calf tightness with running or physical activity
- symptoms that improve with rest
- numbness or tingling in the foot or lower leg
- weakness or heaviness in the leg
- coldness or colour change in the foot
- reduced ability to exercise or run at your usual level.
Because compression may occur only when the calf muscles are activated, an ultrasound performed solely at rest may not demonstrate the changes associated with PAES.
A dynamic duplex ultrasound allows blood flow to be assessed both at rest and during specific movements designed to activate the calf muscles.
What does a PAES ultrasound assess?
The examination begins with assessment of the arteries in the leg, usually from the groin to the ankle, to evaluate arterial blood flow at rest.
The sonographer then focuses on the popliteal artery and popliteal vein behind the knee.
B-mode, colour Doppler and pulsed-wave Doppler ultrasound are used to assess blood flow in different positions.
You may be asked to perform repeated heel raises or plantar flexion movements while the sonographer assesses whether muscle contraction produces changes in blood flow through the popliteal vessels.
The manoeuvres may be repeated several times so different parts of the popliteal artery can be assessed.
The popliteal vein may also be examined during these movements.
Dynamic ultrasound findings are interpreted together with your symptoms and other clinical information. Further imaging or specialist assessment may sometimes be required.
What happens during the test?
No special fasting or medication preparation is usually required.
Please arrive approximately 5 minutes before your appointment to allow time for any necessary paperwork.
Please come wearing comfortable sports clothing and running shoes, as a running or exercise test may be performed in many cases to reproduce your usual symptoms and assess blood flow during activity.
You may also need to remove trousers or other clothing covering the leg so the sonographer can examine the area from the groin to the ankle. Underwear can remain on.
The first part of the examination is generally performed while you are lying down so the arterial circulation in the leg can be assessed.
You will then be asked to stand while the sonographer examines the blood vessels behind the knee.
During the dynamic part of the examination, you may be asked to perform repeated heel raises, plantar flexion or exercise, depending on your symptoms and the assessment required.
If running usually brings on your calf pain, tightness or other symptoms, the sonographer may ask you to perform a short running test before repeating the ultrasound measurements.
If a particular exercise, running intensity or leg position reliably reproduces your usual symptoms, please tell the sonographer.
The examination usually takes approximately 20–30 minutes per leg, although it may take longer if exercise testing is required.
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 finding that requires urgent medical attention, this will be communicated promptly to the referring doctor and appropriate next steps will be arranged.
