December 27, 2001	Thursday	Shawwal 11, 1422

BOSTON, Dec 26: The massive magnets of an MRI machine can help doctors detect most of the narrowed arteries in patients with heart disease, according to research by an international team of doctors published in Thursday’s New England Journal of Medicine.

The results could give doctors a new tool for quickly identifying which patients require surgery.

The beauty of the MRI heart scan is that, unlike the standard test for heart disease, known as coronary angiography, an MRI — magnetic resonance imaging — does not require cutting into the body.

Up to one third of people who receive coronary angiography do not need surgery to bypass or reopen heart arteries, said Dr. Warren Manning of Beth Israel Deaconess Medical Center in Boston. In such cases, a pumping problem may be caused by heart muscle damaged by infection, alcohol or some type of poison.

The MRI test, he told Reuters, “is a way to identify those patients.”

Manning and his team found the MRI scans were accurate 87 percent of the time when it came to pinpointing narrowed arteries feeding the heart muscle.

The beauty of the study, he said, was that it included patients treated at several medical centers around the world and involved doctors who did not specialize in MRI scans of the heart, making it a good real-world test of MRI heart scans.

The scans were made possible by a technique that can take a moving heart and freeze it in time by snapping 80-millisecond-long images at the same point during each heartbeat and breathing cycle.

One disadvantage of the technique was that it took more than an hour, but Manning said in a telephone interview the time was now down to about 20 minutes.

Conventional coronary angiography involves taking X-rays of the heart after a dye has been released through a hollow tube inserted into an artery in the thigh and then threaded into the heart’s arteries. That technique was used in this study to check the MRI scans for accuracy.

An MRI heart scan has other disadvantages. It cannot pinpoint blockages in as many locations as angiography, and several segments of the arteries could not be evaluated.

In addition, if doctors find a narrowed artery using conventional angiography, they can sometimes immediately reopen it with an inflatable balloon. If an MRI scan pinpoints a problem, patients have to undergo surgery anyway.

In an editorial in the Journal, Drs. Stephan Achenbach and Werner Daniel of the University of Erlangen in Germany said although MRI scans, along with other noninvasive techniques for imaging the heart, are constantly improving, they “provide no means of treatment.”

Thus, they said, use of the newer test “does not seem clinically advisable” in patients who develop chest pains during exercise or have other symptoms that make it likely they will need some type of heart disease surgery.

The value of a noninvasive test, they said, may be to rule out heart disease in patients with a low likelihood of having it in the first place.

Manning said for a patient who has never had a heart attack, yet whose heart is not pumping properly, an MRI heart scan “may be an ideal tool” for determining that narrowed arteries are not the problem.

The study was funded in part by Philips Medical Systems of the Netherlands, which makes MRI machines.—Reuters