Figure 6b. Portal vein thrombosis. (a) Subcostal oblique US image shows the bifurcation of the portal vein into right and left branches. Echogenic material is seen in the vessel lumen (arrows). An acute thrombus may be anechoic and identified only at color flow imaging as a flow defect. (b) Subcostal right paramedian US image shows the long axis of the main portal vein (MPV) with a distal thrombus (T).