Popliteal vein thrombosis- on arterial Doppler study

This elderly male patient has cellulitis of the left leg. I was requested to do an arterial Doppler study of the affected lower limb. What I found was interesting:
This is the left femoral artery: normal triphasic pattern with normal PSV (peak systolic velocity) and EDV (end-diastolic velocity).

This is what I found in the popliteal region: normal flow in the left popliteal artery again... but observe that thick echogenic, inhomogenous cord like structure superficial to the popliteal artery. It showed absolutely no

flow signals on color Doppler imaging.

 

I tried to compress the cord like structure ( obviously the left popliteal vein).....absolutely impossible.

This is the appearance of the popliteal vein and popliteal artery. Diagnosis: left popliteal vein thrombosis

For more on this topic: http://www.ultrasound-images.com/vascular.htm#Popliteal_vein_thrombosis
Also: http://ultrasound-videos.blogspot.in/2010/09/popliteal-vein-thrombus-color-doppler.html