I had an US done a few months ago and after examining them myself, I have noticed a discrepancy in one of the results. The HEPATIC VEIN waveform is normal (tetraphasic). The color doppler shows red and my understanding is that it should show blue antegrade ( toward heart). My understanding is that there is a short period of flow reversal (right atrial contraction known as A-wave and V-wave). My laymans guess is that the image was frozen during this A-wave or V-wave contraction. Another scenario is that it was done during valsalva maneuver. I was on my side for a time. I tend to lean toward the latter explanation because the spectral waveform shows both A and V wave above baseline but normal. It makes sense that the added pressure of lying on your side would show a more pronounced A and V-wave. Thoughts anyone?