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 (echocardiography) 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 (DVS), and the superficial venous system (SVS) are looked at. The great saphenous vein (GSV), and the small saphenous vein (SSV) 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. Three anatomic compartments are described (as networks), (N1) containing the deep veins, (N2) containing the perforator veins, and (N3) containing the superficial veins, known as the saphenous compartment. This compartmentalisation makes it easier for the examiner to systematize and map. The GSV can be located in the saphenous compartment where together with the Giacomini vein and the accessory saphenous vein (ASV) an image resembling an eye, known as the 'eye sign' can be seen. The ASV which is often responsible for varicose veins, can be located at the 'alignment sign', where it is seen to align with the femoral vessels.
On ultrasound at the saphenofemoral junction in the groin, the common femoral vein (CFV) with the GSV and the common femoral artery (CFA) create an image called the Mickey Mouse sign. The CFV represents the head, and the CFA and GSV represent the ears. The examination report will include details of the deep and the superficial vein systems, and their mapping. The mapping is drawn on paper and then drawn on the patient before surgery.
The use of ultrasonography in a medical application was first used in the late 1940s in the United States. This use was soon followed in other countries with further research and development being carried out. The first report on Doppler ultrasound as a diagnostic tool for vascular disease was published in 1967–1968. Rapid advances since then in electronics, has greatly improved ultrasound transmission tomography.
Medical uses
It allows the examiner to evaluate the gross anatomy of the venous networks as well as the blood flow direction, which is crucial in determining vein pathology. It has become the reference standard used in the assessment of the condition and hemodynamics of the veins of the lower limbs. The normal physiological blood flow is antegrade, flowing from the periphery towards the heart, so that the evidence of an opposite, retrograde flow might indicate a pathology. The presence of a reflux is likewise of note; a reflux when not isolated in a vein (as simply retrograde), means that the blood flow is bi-directional where once the flow had been only antegrade.
Risks
No contraindications are known for this examination. Ultrasonography does not involve the use of ionizing radiation, and the procedure is harmless and can be safely used on anybody of any age. A World Health Organization report published in 1998 supports this.
Preparation
No preparation is normally necessary for this examination, but if a complementary study of abdominal veins is also required, the patient will be asked to fast for 12 hours beforehand. The sensitivity and specificity measurements are around 90%.