Stenosis and Plaque Imaging
Vulnerable Plaque (Unstable Plaque, or, High Risk Plaque)
Medicine for treating atherosclerosis, including cardiovascular and cerebrovascular diseases, has undergone a paradigm shift. Traditional atherosclerosis risk factors such as stenosis (artery blockage or clogged artery) are giving way to direct assessments of the risk of plaque rupture which is the primary cause of artery blockage downstream. By looking beyond the stenosis of Lumen and imaging directly the high-risk features of the plaques (the vulnerable plaque) themselves, physicians can plan for the most suitable treatment to effectively prevent cardiovascular diseases, such as Myocardial Infarction (i.e., Heart Attack), or cerebrovascular diseases, such as Ischemic Stroke. For more information:
- From Vulnerable Plaque to Vulnerable Patient – A Call for New Definitions and Risk Assessment Strategies (Circulation consensus report)
- The BioImage Study: novel approaches to risk assessment in the primary prevention of atherosclerotic cardiovascular disease–study design and objectives (the High-Risk Plaque Initiative, which uses MRI-PlaqueView)
- Treating Arteries Instead of Risk Factors: A Paradigm Change in Management of Atherosclerosis (Stroke 2010)
Stenosis Imaging and Plaque Imaging
Carotid bruit, the systolic sound heard over the carotid artery area, is an initial assessment of carotid stenosis. Today, Vascular Ultrasound (including Doppler Ultrasound) has been widely used for stenosis assessment. In addition, X-Ray, MRI, and CT Angiography have also been used for stenosis assessment. There are several new developments to look beyond the stenosis of the lumen and to imaging directly the high-risk features of the vulnerable plaque themselves. The intravascular plaque imaging, primarily for coronary artery, include Intravascular Ultrasound (IVUS) and Intravascular Optical Coherence Tomography (OCT). On the other hand, the non-invasive plaque imaging, primarily for carotid artery, include:
- Ultrasound with IMT, acoustic, mechanical, or plaque analysis;
- MRI of Atherosclerosis.
Non-invasive Ultrasound Imaging of Carotid Atherosclerosis
This field has been extensively studied for many years. VPDiagnostics is conducting a NIH sponsored research to develop tools to characterize the carotid plaque composition from non-invasive ultrasound and to compare the results with those from MRI, in order to validate the potentials of ultrasound in carotid plaque imaging.
Magnetic Resonance Imaging (MRI or MR Imaging) provides valuable non-invasive image information for probing the features of the atherosclerotic artery wall. MRI provides multiple contrast weightings that exhibit high and variable contrast between tissues. These features have made MRI the de facto standard for characterizing atherosclerosis, particularly carotid plaque. At PubMed, There are more than more than 1600 publications with the keywords of MRI AND (Atherosclerosis OR Plaque) AND Carotid. For More Information:
- MRI of Carotid Atherosclerosis: clinical implications and future directions (review appearing in Nature Reviews)
- Looking Beyond the Lumen to Predict Cerebrovascular Events (a Stroke editorial by Winfried A. Willinek, MD)
Applications of MRI/Ultrasound atherosclerotic plaque imaging include:
- Risk Stratification of atherosclerotic vascular diseases – for both Primary Prevention and Secondary Prevention;
- Preventive Treatment Planning;
- Timely and Quantitative Assessment in Pharmaceutical and Other Trials;
- Population Studies.
Carotid Plaque section provides some details and selected literature for application of carotid plaque.