Investigations

Diagnosis of a DVT is confirmed by the following:

Ultrasound Doppler Studies

Colour Doppler Ultrasound evaluates the flow of blood as it passes through a blood vessel. It combines the effect of the ultrasound, (where reflected sound waves are converted by a computer to form a picture of the blood vessel, in this case) and the Doppler Effect (where movement of the blood cells causes a change in pitch of the reflected sound waves, which provides a picture of the flow of blood through a vessel).

Venogram

A venogram is an accurate (but rarely necessary) way of assessing veins, their size and condition, using a special dye which is injected into the vein, and which shows up on X-Ray. In the case of diagnosing a DVT, an ascending venogram would be used, and it would demonstrate the blockage in the vein higher up.

The contrast medium used can, in itself, induce thrombosis.

Amended April 2008