December 27, 2001

BOSTON (The Boston Globe) - A technique developed at Boston's Beth Israel Deaconess Medical Center could help doctors see artery disease without making any

incisions in the patient, researchers report in Thursday's New England Journal of Medicine.

Using a magnetic resonance imaging machine, researchers at six sites in the United States and Europe tested 109 patients for blocked coronary arteries. They reported that the test was accurate 72 percent of the time.

Coronary artery disease is the leading killer of Americans. The standard way to diagnose the disease is with an angiogram, a procedure that involves making a slit in the groin area, threading a catheter through blood vessels to the patient's heart, and injecting radioactive dye to make blood flow visible. Blockages can then be seen with an X-ray machine.

The new findings raise hope that for some patients with relatively mild symptoms, there could soon be a safer, more convenient, less expensive way to detect the disease.

Magnetic resonance imaging is one of several techniques being explored as alternatives to conventional coronary angiograms.

"We're delighted with the results," said Dr. Warren J. Manning of Beth Israel Deaconess, who has worked for 15 years to detect coronary artery disease with MRI, a technology better known for taking pictures of injured knees or brains than for capturing images of the moving heart.

With MRI, a giant magnet sends radio waves through the body to create images. The device is excellent at delivering pictures of soft tissue, but has had trouble getting a clear view of arteries, which are blurred by the constant motion of the heart and lungs. The new technique gets around that problem by using specially designed software.

An MRI costs just $1,000, compared to around $5,000 for coronary angiography, and does not require the eight-hour hospital stay needed for angiography. But such use of the MRI technology has yet to be approved by the federal government. Outside the study it is available only for patients deemed too risky for angiography, which carries a small risk of heart attack or stroke.

The study was sponsored by Philips Medical Services, which makes MRI equipment, and by the American Heart Association. The technique tested works only with Philips machines. Other companies that make MRI systems are working on their own techniques, such as General Electric, which has worked with engineers at Stanford University.

Dr. Robert Herfkens, director of MRI at Stanford, said the new study's results were promising, particularly because they involved a relatively large group of patients at far-flung health centers. But he cautioned that MRI and other techniques must be evaluated further before they can be seen as a replacement for conventional angiography.

"It doesn't make me want to run out and sell any of the other diagnostic equipment that we have, yet," he said.

Using a noninvasive test has its drawbacks. For example, in an emergency, doctors cannot immediately insert a balloon to open a blocked artery, as they can with conventional angiography.

But of more than 1 million Americans who undergo coronary angiography each year, between 20 and 40 percent either do not have coronary artery disease or do not have a serious enough case to warrant surgery. It is those patients that Manning and his colleagues hope to target.

Manning, section chief of noninvasive cardiac imaging at Beth Israel Deaconess Medical Center, where lead author Dr. W. Yong Kim also works, said: "There are people who present to their doctor with shortness of breath. Their stress test is inconclusive. They've never had a heart attack. The likelihood that the cause of their sympoms is not from coronary disease is about 50 percent. That is probably going to be the first group of patients that is going to benefit."

Most promising, he said, was that the test was most accurate at detecting one of the most severe forms of disease, left main artery or three-vessel disease, whose patients are most likely to live longer as a result of timely treatment.

Finding an accurate, noninvasive test for coronary artery disease has sparked intense competition, even within Beth Israel Deaconess, where Dr. Melvin E. Clouse uses computed tomography, commonly known as a CAT scan, to check arteries for calcium that may indicate blockage.

But some doctors worry that noninvasive tests may be overused for screening, that ease of use will prompt healthy patients to seek testing and run the risk of a mistaken diagnosis that could prompt unnecessary procedures. Manning said it was important to note that his study did not evaluate MRI as a general screening tool.

An editorial accompanying the article urged doctors to move quickly to improve noninvasive procedures and make them available.

"With the recent advances," wrote Drs. Stephan Achenbach and Werner Daniel of the University of Erlangen in Germany, "the issue should be not if, but when, and for which patients."