Venous Insufficiency

The main use of CW Doppler in venous insufficiency is in assessing reflux in the major deep veins of the lower extremity (common femoral, femoral, and popliteal veins). This procedure is most effectively performed with the subject standing. To the extent possible, weight should be shifted to the contralateral leg. A bidirectional CW Doppler with a stereo audio signal and printout is recommended. For venous work an ultrasound frequency range of 5 to 7 MHz is suggested. As a quick review, the pencil-like probe of the CW Doppler should be aligned toward the flow and at an angle of approximately 60 degrees to the anticipated flow streamline. Unlike Duplex Ultrasound, with CW Doppler the exact path of the target vein is not well defined. Therefore, in practice the operator will have to adjust the probe angle manually to obtain the maximum signal (audio level and velocity level). The concept is quite simple; target veins are assessed for reversal of flow velocity after rapid manual limb compression and release. The more reversal, the more reflux. In terms of diagnostic criteria, a normal vein demonstrates no evidence of reflux using this technique. Flow reversal can be assessed both by audio signal and by examination of velocity versus time printouts.17

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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