A Look Inside

1. While lying down, the patient is injected with a contrast agent that helps highlight the heart's blood vessels

2. A table slides the patient into the scanner as the X-ray tube circles the body for 5 to 8 sec.

3. The detector array records the X rays. Each complete loop creates a spiral slice of the heart composed of 64 thin slices, offering exceptional resolution

4. The scanner's computer reconstructs the spiral slices into hundreds of 2-D images, much like slices from a loaf of bread

5. The doctor's computer processes the slices, creating a 3-D composite that can show the pumping action of the heart

Sources: GE Healthcare; Siemens TIME Graphic by Lon Tweeten and Kristina Dell