valsalva maneuver

1- the patient is asked to do valsalva maneuver while the common femoral vein is being imaged transversely.

2-a normal response results in complete retardation of flow within the vein and resultant venous dilatation , the diameter increasing by at least 50%.

3-absence of this normal response is seen in intra luminal venous thrombosis,or external pressure applied on the vein by a pelvic tumor .

4- it could be done also with congestive heart failure