Venography is an x-ray exam that uses an injection of dye to show how blood flows through your veins. Your doctor may use it to find a blood clot, or to prepare for dialysis.
For this test, a contrast dye is injected into the renal veins with a catheter. Then X-ray images are taken within seconds. Epinephrine injected first, may allow for better images. Venography is being done less often, as tools such as Doppler ultrasound have improved.
Complications are rare, but include leaks around the site of the injection. Also, some people are allergic to the solution.