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PART 4 — PERIPHERAL VENOUS
Figure 14-23 Split screen view demonstrating the full com- pression of the common femoral vein (CFV ) indicating the thrombus-free status of the vein at that location. Note how the vein walls coapt together (arrows). The common femoral artery (CFA) is also seen.
“compression ultrasound.” After watching the vein compress, the examiner eases up, and the vein will reopen. The walls of a normal vein appear thin and smooth. Valve sinuses may be apparent as slight dila- tions in the vein wall. Valve leaflets may be seen as thin white structures within the sinus freely moving in the blood stream.
NORMAL COLOR AND SPECTRAL DOPPLER
Spectral Doppler and color information can be added to the information gathered from visualizing the compressions of the veins. Laboratory accredi- tation protocols presently require spectral Doppler signals at key levels. Venous Doppler signals should
Figure 14-24 A spectral Doppler waveform obtained from the mid-thigh level of the femoral vein (FV ) illustrating normal re- spiratory phasicity.
Figure 14-25 A spectral Doppler waveform obtained from the popliteal vein illustrating a normal augmentation in flow (arrow) with a distal compression.
display the following five characteristics. First, with modern ultrasound equipment, spontaneous Dop- pler signals should present within all major vessels. Second, spectral Doppler signals in a normal vein should be phasic with respiration (Fig. 14-24). Third, compression of the leg below the level of the trans- ducer should augment flow (Fig. 14-25). Fourth, venous Doppler signals should cease with proximal compression or the Valsalva maneuver (Fig. 14-26). Lastly, venous Doppler signals from lower extremity veins should be unidirectional, toward the heart.
Color flow imaging should also display the same attributes as a spectral Doppler. With proper equip- ment setting, color should be seen completely filling the vessel lumen (Fig. 14-27).
Figure 14-26 A spectral Doppler venous waveform illustrating the absence of flow during a Valsalva maneuver.