Would dvt behind the knee be obvious on leg scan?

Often!: No test is 100% accurate. Discuss with your doctor and see if he is confident with the results of the ultrasound. Your doc will compare that result with the symptoms you are having and decide if another diagnosis is more likely, or that you need further testing to find out what is causing the pain.

Yes: The usual test to detect deep vein thrombosis is an ultrasound. They are more than 95% accurate. More recently, Emergency Departments have developed the ability to perform a more abbreviated test in the ER; these are also very accurate, nearly the same as the formal full scan. The popliteal fossa (behind the knee) is a little more challenging, but still very reliably diagnosed by this technique.

Yes: that will be the most obvious one because of the unique location of the vein. scan in general is very accurate when it comes to DVT.

Yes,: if you are referring to an Ultrasound scan for DVT evaluation.

Venous Doppler.: The physical examination of the leg is notoriously inaccurate for the diagnosis if DVT. In the appropriate clinical setting (immobilization, recent surgery), a venous Doppler would be the necessary test. May also show up on a CT or MRI of the thigh or lower leg, but the venous Doppler is typically performed and is sufficiently accurate.