page_title: Ultrasonography of chronic venous insufficiency of the legs
section_title: Procedure
hierarchical_section_title: Ultrasonography of chronic venous insufficiency of the legs / Procedure
caption_attribution_description: English: Paraná maneuver: Checking perforation veins in muscle systole ans diastole
context_page_description: Ultrasonography of suspected or previously confirmed chronic venous insufficiency of leg veins is a risk-free, non-invasive procedure. It gives information about the anatomy, physiology and pathology of mainly superficial veins. As with heart ultrasound studies, venous ultrasonography requires an understanding of hemodynamics in order to give useful examination reports. In chronic venous insufficiency, sonographic examination is of most benefit; in confirming varicose disease, making an assessment of the hemodynamics, and charting the progression of the disease and its response to treatment. It has become the reference standard for examining the condition and hemodynamics of the lower limb veins.
  Particular veins of the deep venous system, and the superficial venous system are looked at. The great saphenous vein, and the small saphenous vein are superficial veins which drain into respectively, the common femoral vein and the popliteal vein. These veins are deep veins. Perforator veins drain superficial veins into the deep veins.
context_section_description: The patient will need to be in an upright position to enable a proper study of blood flow direction
  Chronic venous insufficiency is where the veins cannot pump enough blood back to the heart. It results when the vein dilates secondary to a vein wall disease or when normal functioning of the valves, which serve to keep blood flowing to the heart and to prevent reflux, become damaged and/or incompetent (the dilation of a vein will prevent valves to close properly). This incompetence will result in an reversed blood flow through the affected vein or veins. It can result in varicose veins, and in severe cases venous ulcer. The reversed blood pools in the low third of legs and feet.
  Unlike the arterial ultrasound study, when the sonographer studies venous insufficiency, the vein wall itself has no relevance and attention will be focused on the direction of blood flow. The objective of the examination is to see how the veins drain. In this way, venous ultrasonography has at times become a hemodynamic examination which is reserved for experienced sonographers who have completed hemodynamic studies and training and have acquired a deep knowledge of this subject.
  Also, unlike ultrasonography of deep venous thrombosis, the procedure focuses mainly on superficial veins.
  
  Also, unlike the arterial ultrasound examination, blood velocity in veins has no diagnostic meaning. Veins are a draining system similar to a low pressure hydraulic system, with a laminar flow and a low velocity. This low velocity is responsible for the fact that it can only be detected spontaneously with the Doppler effect on the proximal and larger femoral and iliac veins. Here the flow is either modulated by the respiratory rhythm or is continuous in cases where the flow is high. The thinner veins do not have a spontaneous flow. However, in some circumstances the blood flow is so slow that it can be seen as some echogenic material moving within the vein, in "spontaneous contrast".  This material can easily be mistaken for a thrombus, but can also easily be discounted by testing the vein's compressibility.
  To evidence the blood flow direction there are some techniques that the examiner can use to accelerate blood flow and show valvular function:
  Manual squeezing and releasing – the examiner can compress the vein below the probe which will push the blood in its normal antegrade direction. On releasing the pressure if the valves are incompetent the flow will appear as a retrograde flow or reflux, greater than 0.5 sec.
  Paraná maneuver makes use of a proprioceptive reflex to test venous muscle pump induced flow. (Proprioceptive refers to a response to a perceived stimulus especially with regard to movement and position of the body). A slight push to the waist, triggers a muscle contraction in the leg, in order to maintain posture. This maneuver is very useful for studying deep vein flow and detecting valvular incompetence, mainly at the popliteal vein level, (at the back of the knee) and to check perforator vein incompetence. It is very useful when legs are painful or very edematous (swollen with fluid).  
  Flexing the toes and feet and extending on tiptoes can all be very useful in detecting perforator vein incompetence. These movements unleash a muscle contraction which compresses deep veins. If a perforator valve is incompetent then a reflux from the deep to the superficial through the perforator vein will be registered.
  Valsalva maneuver – when the patient performs this maneuver, he or she, increases intra-abdominal venous pressure. If the great saphenous valve at the sapheno-femoral junction is incompetent, a reflux will appear.
  Normal blood flow is antegrade (going to the heart), and from superficial to deep veins via perforator veins. However, there are two exceptions: firstly, the GSV collaterals, (the veins that run parallel), drain the abdominal wall and have a flow from top to bottom so that when an examiner tests the saphenofemoral junction, a false positive diagnosis might be made; secondly, in the flow from the sole of the foot venous network around 10% 
caption: Paraná maneuver: checking perforators
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