One of the challenges to taking good diagnostic pictures of the coronary arteries is that blood is always flowing through them. The heart doesn’t stop pumping blood just so a radiologist can get clear, stop-action pictures.

But now, there’s a technology that overcomes that motion problem. It’s a 64-slice CT scanner, and it came to Good Samaritan Regional Medical Center last winter to become the cornerstone of the hospital’s new computed tomography angiography (CTA) program launched this spring.

“This new Toshiba Aquilion™ 64-slice CT scanner will enable us to give our patients a true cardiacgated exam,” said Ron Aldred, radiologist and the hospital’s CT supervisor.

“While it’s not meant to be used as a screening tool, it’s a great diagnostic tool that can detect cardiac problems even on patients who are asymptomatic.”

The new scanner uses the patient’s own heartbeat to “gate” (the term is used here as in: “allow” or “open”—as does a gatekeeper) access for the X-ray camera images. When the heart is beating, the scanner remains off. When the heart is resting between beats, the scanner quickly turns on. This means it minimizes a patient’s exposure to radiation, even as it produces very sharp pictures.

Aldred said that CT angiography is not meant to replace conventional coronary angiography, which was invented in the 1950s and is still considered the gold standard of coronary investigation. Rather, it’s meant to supplement what’s already being done for patients and address what are drawbacks, for some people.

With conventional coronary angiography, patients are required to hold their breath for 30 to 40 seconds to inhibit motion. The 64-slice scanner requires only 10 to 12 seconds of breath-holding. Also, while conventional angiography can detect if arteries have narrowed, it cannot precisely detect the amount of atherosclerosis within artery walls.

The 64-slice CT can be used on a greater range of patients to more accurately visualize soft plaque and measure coronary stenosis (narrowing). And it does so very quickly. Whereas typical angiography produces heart images at 15 to 30 frames a second, the new CT scanner can acquire 64 simultaneous slices (images) of 0.5 mm with each 400-millisecond gantry revolution.

“CT technology is also more patient friendly,” Aldred said. “It’s less invasive in that it uses an IV in the arm, rather than a puncture in the groin; and the procedure takes about one to two hours, rather than the six to eight hours required for typical angiography.

“Because the scanner gives such wonderful diagnostic images, we can envision applications for post-op care for cardiac bypass patients and for those who have had stent placement,” Aldred added. “We’re pretty impressed with what this technology can do.”