PERSONAL HEALTH : New, Speedier Test Detects Heart Disease
Ever wonder what your chances are of having heart disease?
A new, five-minute scan can evaluate your risk long before a heart attack occurs by detecting calcium-ridden plaque in major blood vessels.
This high-speed scan, called the Ultrafast CT, will become as commonplace as mammography, proponents predict. It works on the same principle as conventional computed tomography (CT), which scans the body and produces computer images of tissue to detect disease and other abnormalities. But the new version works 10 times faster, a speed crucial to capturing blur-free images around the beating heart.
It is now used at three Los Angeles-area sites and about 15 other locations nationwide, says Douglas Boyd, chairman of Imatron Inc., the Ultrafast’s South San Francisco manufacturer. The unit, developed by UC San Francisco scientists, can also detect faulty cardiac valves and heart tumors.
But some experts caution that the new scan isn’t perfect.
“This test looks good, but we don’t yet know everything about calcification and heart disease,” says Dr. Donald P. Harrington, a cardiovascular radiologist at State University of New York, Stony Brook, and vice chairman of the American Heart Assn.’s council on cardiovascular radiology.
In the past month, at least two medical journals have published reports about the merits of the new scan in detecting coronary artery disease.
Men over age 35 and women over age 40, along with anyone at special risk for heart disease, are considered prime candidates for the $300 to $400 test, which is not usually reimbursed by insurance. In some cases, experts say, the scan might rule out the need for angiography, a procedure that costs $1,500 or more and involves injecting dye into blood vessels so they show up on X-rays.
Ed Singer, a 64-year-old Westwood marketing consultant, recently underwent the test to allay his “gnawing fear” that he, like other family members, will suffer heart disease.
He lay motionless on a padded gurney at Harbor-UCLA Medical Center in Torrance as a technician hooked up electrodes for routine electrocardiogram monitoring. He was then rolled under a doughnut-shaped detector ring, a stationary device that receives the image beam.
“We are scanning only about a six-inch area,” explained Dr. Bruce H. Brundage, UCLA professor of radiological sciences, who performed the test. “The radiation dose is less than that from a conventional CT scan. It is equivalent to the dose from an abdominal X-ray.”
Minutes later, Singer watched as the radiologist assessed the pictures on a monitor and computed Singer’s calcium score, obtained by comparing the amount detected to norms for patients of the same age.
Experts have known for several years that calcium buildup in the coronary arteries increases the risk of heart disease. And scientists believe that risk increases as calcium increases, Harrington says. (Arterial calcium, a plaque byproduct, is unrelated to dietary calcium.)
Brundage pronounced Singer at about average risk for his age. It was not the news he had wished for, but Singer said he had no regrets about taking the test.
The greater the number of risk factors for heart disease, the greater the chance calcium will show up on the scan, UC Irvine researchers recently reported in the American Journal of Cardiology. The study included nearly 600 men and women.
Mayo Clinic and University of Michigan researchers recently compared angiography to the scan in 100 patients under 60. All those with significant disease evident on the angiogram had detectable calcium on the CT scan, the researchers reported in the current issue of Radiology. But none of the 25 patients free of calcification had significant narrowing of vessels on the angiogram.
“If you don’t have evidence of calcification, you can be pretty sure you don’t have significant coronary artery disease,” says Harrington. “The tricky part is, if you have calcification, no one can definitively assess your risk.”
Proponents say the scan might be useful in monitoring the effects of lifestyle changes and medication meant to lower cholesterol and reduce plaque. It might even spare some people from taking cholesterol-lowering medication unnecessarily, experts say, since not everyone with high cholesterol has high levels of calcification.
For more information on the Ultrafast CT scan, call Imatron Inc. ((415) 583-9964) or Heart Check America ((800) NEW-TEST), a support services provider for some sites.
