While noninvasive procedures like the PET Scan and ultrasound can detect many heart problems, sometimes it is necessary to perform an invasive procedure called a coronary angiogram to identify a heart problem. Generally, doctors turn to angiography only after other tests have proven inconclusive or incomplete. In a coronary angiogram, a nontoxic dye is injected into the arteries through a catheter and then viewed through X-ray cameras to detect any vessel blockages.

Coronary angiography is performed at a hospital in a special X-ray-equipped suite called a catheterization laboratory. During the angiogram, the patient is on an examining table under a fluoroscope (X-ray camera). Either the table or the camera is movable so that many different angles of the heart can be seen on the television screen.