the left femoral vein- colour Doppler study

this elderly male patient had redness and mild swelling of the skin over the middle third of the left leg.
This is what we found when we did the colour Doppler study of the left lower limb.
This patient did not have any major pain or tenderness in the thigh.Clinically, he did not have features of deep vein thrombosis. Would you think of this possibility from these Doppler ultrasound images?

                                                                                                                           

The answer: this is a case of Left femoral vein thrombosis. There is near total absence of flow signal in a major part of the left femoral vein. The lack of symptoms is explained by the patient having had anticoagulant treatment for a few days.