JACC: MRI could become effective tool in monitoring lipid therapy
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In the study, Binh An Phan, MD, cardiologist from the Loyola University Health System in Chicago, and colleagues wanted to test the effect of lipid therapy on the amount of cholesterol in artery-clogging plaque, which leads to atherosclerosis.
The study included 120 patients randomly assigned to receive one of three cholesterol treatments: Lipitor; Lipitor plus Niaspan (extended-release niacin); or Lipitor plus Niaspan and colesevelam.
After three years, the 33 patients with identified carotid plaques had a significant reduction in the cholesterol within the plaque. The volume of cholesterol dropped from 60.4 cubic millimeters to 37.4 millimeters, and the percentage of plaque volume consisting of cholesterol dropped from 14.2 percent to 7.4 percent.
“Intensive lipid therapy significantly depletes carotid plaque lipid,” wrote the authors in their conclusion. “Statistically significant plaque lipid depletion is observed after one year of treatment and continues in the second year, and precedes plaque regression.”
MRI scans were used for analysis of plaque size and tissue composition. Traditional imaging technologies, such as angiograms and ultrasounds, show the overall size of the plaque buildup, but MRI scans used in the new study were more precise in showing the amount of cholesterol within the plaque.
The scans were done on patients’ carotid arteries in the neck, rather than their coronary arteries. Subjects were placed in the supine position in the MRI scanner with the neck extended to better position the carotid arteries.
The findings confirmed the researchers' hypothesis that the reason cholesterol medications shrink the overall size of the plaque is because cholesterol is being removed from within the plaque. Thus, using MRI scans to monitor the amount of cholesterol in plaque may help physicians to better determine how well cholesterol medications are working. If an MRI showed cholesterol was not being reduced, more aggressive therapy might be needed, Phan said in a statement.
"In the future, MRI scans may become important and powerful tools to see how medication therapy is working inside arteries," Phan said. "However, our study is just the first step. Additional studies will be needed."
Evan Godt, Writer
Evan joined TriMed in 2011, writing primarily for Health Imaging. Prior to diving into medical journalism, Evan worked for the Nine Network of Public Media in St. Louis. He also has worked in public relations and education. Evan studied journalism at the University of Missouri, with an emphasis on broadcast media.