MRI May Enable Clinicians to Identify Dangerous Atherosclerotic Plaque in Coronary Arteries before they Rupture

According to a press release from Boston University School of Medicine (BUSM), researchers have shown that magnetic resonance imaging (MRI) can non-invasively identify dangerous atherosclerotic plaques in the coronary artery and other vessels.

Noting that because “rupture of vulnerable atherosclerotic plaque, which often occurs without prior symptoms, is responsible for a substantial number of deaths and disabilities worldwide,” new imaging applications that would enable clinicians to identify “atherosclerotic plaques with a high risk for disruption and thrombosis” would allow physicians and patients to initiate preventive measures “before thrombi begin to clog arteries and cause stroke or heart attack.”

Working with a rabbit-based animal model, BUSM researchers used MRI to examine atherosclerotic plaque in vessels pre- and post-rupture. They found that “plaques that were hidden within the vessel wall and pushing the vessel wall outward instead of occluding the lumen had a very high chance of forming a thrombus; plaques that caused vessel narrowing were almost always stable,” which could help to explain “why the most dangerous plaques generally escape detection by x-ray angiography.”

Results from this study were published in an article titled “In vivo Detection of Vulnerable Atherosclerotic Plaque by MRI in a Rabbit Model,” in the May 2010 issue of Circulation: Cardiovascular Imaging. The authors noted that “pretriggered MRI revealed comparable stenosis in stable and vulnerable plaques,” but vulnerable plaques had larger plaque and vessel areas and a higher remodeling ratio compared with stable plaques. Vulnerable plaques were also found to more frequently exhibit “positive remodeling,” in which “the plaque is hidden within the vessel wall instead of occluding the lumen,” and enhanced gadolinium uptake, which is “associated with histological findings of neovascularization, inflammation, and tissue necrosis.”

Based on their findings, the researchers think that MRI can be used to identify stable and unstable plaques in arteries. James A. Hamilton, PhD, professor of biophysics and physiology at BUSM, said that these findings “suggest that MRI may be used as a noninvasive modality for localization of plaques that are prone to disruption.”