Normal hepatic venous waveform. On a color duplex US image, the spectral waveform for a normal hepatic vein shows triphasic flow above and below the baseline. The waveform shows periodicity and is triphasic due to transmitted cardiac activity, similar to the waveform for the jugular vein. The component above the baseline corresponds to atrial systole; the components below the baseline correspond to ventricular systole and the filling phase during atrial diastole.


http://www.google.com.eg/imgres?imgurl=http://radiographics.rsna.org/content/24/3/657/F43.small.gif&imgrefurl=http://radiographics.rsna.org/content/24/3/657.full&usg=__F7-OEFZQVV-SS9oqhkkqgRTZCIk=&h=135&w=200&sz=24&hl=ar&start=4&tbnid=hbLUfp8WZCGr-M:&tbnh=70&tbnw=104&prev=/images%3Fq%3Dvenous%2Bspectral%2Bwave%2Bform%26hl%3Dar%26sa%3DG%26gbv%3D2%26tbs%3Disch:1&itbs=1