New "Real Time" MRI Stress Test Pictures Heart in Motion

	October 11, 1999 - A new type of stress test may soon offer doctors
a safer and easier way to diagnose heart disease, researchers report in the
October 12 issue of Circulation. The new stress test, called fast cine MRI,
offers an alternative for diagnosing coronary artery disease in patients who
are not good candidates for standard stress tests.
	Stress tests measure how well a person's heart handles physical
exertion and can help find a blockage or other problem in the heart's
blood vessels. Thallium stress tests use a radioactive substance injected
into the bloodstream to show how well blood is flowing to the heart muscle.
It is usually done along with an exercise stress test on a treadmill.
	The fast cine MRI stress test uses a new form of high-speed MRI to
view the wall of the heart as it beats. The fast cine MRI is able to capture
the heart's movement at almost the same time the heart is beating, or "real
time."
	Patients receive a drug called dobutamine and are placed in the MRI
machine. Dobutamine works like adrenaline and mimics the effects of exercise
on the heart by increasing the heart rate. It also induces cardiac ischemia,
a reduction in the blood being supplied to the heart.
	With the high-speed imaging, a doctor can check the ability of the
left ventricular wall to move during physical stress. It is an alternative
for patients who are obese, have had heart surgery, or who have lung disease.
However, the fast cine MRI stress test should not be used in patients with
pacemakers, ear implants, metal clips, or ICDs.
	In an accompanying editorial, Dr. Gerald Pohost said, "Perhaps the
most important aspect is that it gives a comprehensive evaluation of the
heart, displaying function, structure, blood flow, and coronary arteries.
Ultimately it should provide everything you need in one package."
	The MRI stress test takes about 35 minutes, says Hundley. The test
was an accurate predictor of heart disease. Among patients who had a negative
MRI stress test, 97% were free of heart disease within the first year of
testing.