CHICAGO - Patients who are given a clean bill of health by an angiogram, yet still suffer heart attacks, could benefit from a noninvasive, magnetic resonance imaging technique that assesses the degree and type of plaque build-up on epicardial coronary walls.
Using a 1.5-tesla cardiovascular MR imaging system from GE Medical Systems, researchers examined the artery walls, rather than just the percentage of stenosis, according to Dr. Zahi Fayad, director of cardiovascular imaging at Mt. Sinai School of Medicine in New York City. Their high-resolution coronary artherosclerotic MRI technique used a fast double inversion, recovery fast spin-echo sequence.
Elements of a lesion that can be spotted by the wall imaging - but cannot be seen on an angiogram - include a crescent shape, a large lipid core and a thick fibrous cap.
"It means that this plaque, structurally, is soft," Dr. Fayad said. "Under stress - mechanical, emotional, disease - this plaque is prone to rupture."
Seventy percent of heart attacks occur in patients who have less than 50% obstruction according to angiography and are considered "normal," noted Dr. Fayad, who presented his team's findings at an RSNA press conference on Monday.
"The obsession with how much occlusion there is in the vessel is wrong," he said. "The question is: 'What makes plaque dangerous and vulnerable?'"
In the Mt. Sinai study, 13 subjects between the ages of 18 and 25 underwent MRI. Of the 13, five were determined to have heart disease by x-ray angiography. In the latter group, vulnerable plaque build-up was two to 10 times thicker than in the healthy group.
"The power of this technique is that we can look at multiple vessels and look for risk. If you monitor their risk factor, you monitor their disease," Fayad concluded. The next stage will be an expanded study with at least 20 patients.
Fayad will present the results of the study in a scientific session on Tuesday November 30 at 10:48am in Room E451A.
By Shalmali PalAuntMinnie.com staff writer
November 30, 1999
