Angiography

Angiography is a medical imaging technique, in which a catheter is threaded through a series of blood vessels, to reach an area of interest. It is guided by imaging techniques, usually fluoroscopy, but it is not restricted to radiologists; it is a basic technique, for example, of invasive cardiology.

Once the catheter tip is in place, a contrast medium is injected through the catheter, making the vessel wall opaque to X-rays, and thus possible to visualize constrictions or tears inside it. While the catheter is in place, other measurements may be taken, such as pressure; cardiac catheterization combines angiography and pressure measurements.

Related techniques include intravascular ultrasonography, with the ultrasonic sound waves generated at the tip of the catheter.