Lower Extremity Venous Examinations
Obstruction of the deep or superficial veins of the legs by thrombus (blood clots), inflammation or compression may result in swelling, pain, tenderness, and discoloration of the affected limb. Several noninvasive test procedures are used to determine the presence of venous thrombosis. The choice of tests will be dependent on your medical history.
Indications for Testing
- Edema, localized tenderness or redness of the limb
- Screening for deep vein thrombosis in high-risk patients
- Identification of source for pulmonary embolic material
- Identification and evaluation of venous valvular incompetence
- Monitor progression of anticoagulant therapy
- Preoperative saphenous vein mapping
Duplex scanning and Doppler Color Flow Imaging may be performed to identify and localize deep or superficial venous thrombosis. The technique is similar to that described for Duplex Scanning of the Lower Extremity Arteries. You will be asked to disrobe from the waist down (except for undergarments) and to wear a hospital gown. The examiner will assist you to lie on your back on the examination table with your knees slightly bent and your hips rotated outward. The foot of the table will then be lowered to that your feet are lower than your head. Acoustic gel will be placed along the course of the veins in the thigh and calf. The technologist will obtain images of the veins and signals from the flowing blood using ultrasound. The examiner may use gentle pressure with the ultrasound probe to compress the veins, a technique which is useful to assure absence of clot in the veins. Using duplex and color flow imaging techniques, clots within the veins can be visualized and proper functioning of the vein valves can be confirmed. Venous Duplex Scanning is now considered to be the single most accurate method for determining the presence of deep vein thrombosis or thrombophlebitis of the superficial veins.
Varicose veins along with other signs may indicate that the valves in the veins of our legs are not functioning properly (incompetence). The degree of valvular incompetence can be determined using Duplex Scanning and are similar to the above technique to rule-out DVT with a greater emphasis on valve function.