They monitored how volunteers' arteries coped with the fatty drink and checked for calcium deposits in their coronaryarteries, a sign of heart disease.
Used diagnostically in patients with coronary artery disease to determine which arteries should receive a stent, it involves inserting a guide wire that measures pressure into the artery instead of relying solely on the traditional coronary angiogram.
Dr. Robert Bonow, chief of cardiology at Northwestern University's Feinberg School of Medicine, notes that about 10 percent of study participants with a positive test had normal coronaryarteries, and 17 percent of those with a normal test had coronarydisease.
One woman had calcified deposits in her coronaryarteries that looked strikingly like someone with serious heart disease showing up in the hospital today.
But in people who are older than this - as most of the nurses in the study were - it can be the first sign of coronary heart disease, where the heart's arteries become blocked by fatty deposits.
The stress thallium and the cardio catheterization, in which dye is injected in the coronaryarteries(arteries of the heart muscle) are both useful in telling us if there is any coronary artery disease.