To map both the deep, superficial and perforating veins in the leg paying particular attention to the function of valves
The patient will need to have the leg under investigation bare from the groin to the foot. Thus they should wear loose fitting clothes or be prepared to remove the outer garments of the lower extremity. Patients of course will be provided with a gown and the investigation is performed in complete privacy.
The patient is examined in a standing position to assess the presence of valvular insufficiency. The study is non-invasive and does not involve the injection of any dye. Gel is applied to the skin and the ultrasound probe is run up and down the leg following the veins. The sonographer will be required to squeeze the patient’s calf quite regularly to identify areas of valvular incompetence. Occasionally the probe will have to be pushed quite firmly to assess the deeper veins.
A comprehensive examination of all the veins in a leg may take up to an hour. Both legs can be examined in the one sitting but often it is preferable to do them one at a time.
Venous incompetence is identified by the demonstration of reversal of blood flow in a downward direction following the brief increase in upward blood flow caused by squeezing the calf. Perforating vein valvular incompetence is identified by the demonstration of blood flow from the deep veins to the superficial ones (the opposite of the normal arrangement).
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