St. John’s Hospital installed and began using the latest computed tomography (CT) imaging software and machinery, also known as a 64-slice CT scanner, July 31
The device produces precise diagnostic pictures within five to 10 seconds, enabling one to “freeze” motion and better define certain disease processes. St. John’s new scanner is the Lightspeed Volume Computed Tomography system offered by GE Healthcare.

Features include production of images much faster than that possible with current four-slice and 16-slice scanners, improved fine detail resolution, and improved post-processing to generate three-dimensional images for treatment planning.

“This technology could dramatically alter the way we currently treat patients with suspected coronary disease and chest pain,” says Kelvin Van Osdol, M.D., chairman of Cardiovascular Services.

To produce a CT image, computer-driven machinery passes X-rays through the body, producing digitized signals that are detected and reconstructed. Each X-ray measurement lasts just a fraction of a second and represents a “slice” of an organ or tissue. The greater the number of detectors, the better the speed and resolution of the picture. A computer then uses these slices to reconstruct highly detailed, 3-D images of the heart, other organs, and blood vessels throughout the body. In most cases, a patient is injected with a contrast solution to increase the visual detail.

Revolutionary potential

Doctors say the 64-slice CT has the potential to revolutionize many fields of medicine, from identifying narrowed arteries to the brain, to finding tumors, to plotting surgeries. But the most radical transformation may come in the way doctors evaluate patients for coronary heart disease.

For patients experiencing symptoms associated with heart disease, the new scanner provides improved resolution of images of the coronary arteries that may make clear the need for more invasive testing.

Lisa Miller’s family history

Fifty-four-year-old Lisa Miller (pictured on the cover), a credential coder for St. John’s Cardiac Catheterization Lab, was one of St. Johns’ first 64-slice CT patients.

Miller, a fit nonsmoker who has a history of heart disease on both sides of her family, was grateful her CT revealed soft plaque in two of her vessels, but no blockages.

“My mother has had three stents put in and my father had quadruple bypass surgery in the 1970s, so I was concerned about my heart even though I’ve never had any symptoms of heart disease,” she says. “After the scan, which took about an hour, Dr. Van Osdol went over my results with me. I also discussed them with my internal medicine physician later. The soft plaque I have in two of my vessels isn’t anything to be concerned about now, but it is something to keep an eye on. I watch what I eat and my cholesterol is low, but after learning about the soft plaque, I’ve started running again.”

Miller also encouraged her five children, who are ages 21 to 31, to eat sensibly and exercise to try to offset their family history of heart disease as much as possible.

Before the 64-slice CT

Until 64-slice CT, the only certain way to tell whether a patient’s coronary arteries were blocked was with an invasive technique called angiography. In it, doctors snake a catheter from a blood vessel in the groin up to the heart, then inject dye into the coronary arteries and watch the results on an X-ray screen.

Nearly 1.5 million patients undergo angiography in the U.S. each year. Many discover problems that may require interventions such as stents or bypass surgery. But in nearly a third of the cases, the results turn out to be normal.

Doctors hope that many of these relatively healthy patients can be ruled out if they get CT scans first. That would save patients the small, but real risks of angiography: a blood clot or torn artery.

"Within just the last few years, CT scanning technology has made incredible strides as a diagnostic tool," says Dr. Van Osdol. "As recently as last year, the technical gold standard was 16-slice, which required the patient to hold their breath for 25-40 seconds in the time it took to perform the scan, as compared to eight to 12 seconds with the 64-slice CT scanner."

The 64-slice scanners cost $2.5 million; this one cost St. John's about $1.2 million because the health system was able to upgrade the existing radiology facility instead of building a new one.