AorticandCarotidMagneticResonanceImage(MRI)Imaging创新.pptVIP

Aortic and Carotid Magnetic Resonance Image (MRI) Imaging Can identify plaque components such as fibrous cap, lipid core, calcium, hemorrhage, and thrombosis (vunerable plaques have thin fibrous cap and large lipid core) Non-invasive and no radiation Computerized morphometric analysis involves following edge of significant contrast, providing measures of total vascular and lumen area, the difference being the vessel wall area (Image Pro-Plus, Media Cybernetics). Image-specific error of 2.6% for aortic and 3.5% for carotid plaques allows accurate measurement of changes in plaque size of 5.2% for aortic lesions and 7% for carotid lesions (Corti et al., 2001) MRI Assessment of Thoracic Aorta Plaque Challenges include obtaining sufficient sensitivity for sub-mm imaging and exclusion of artifacts from respiratory motion and blood flow. Multicontrast approaches include performing T1-,PD-, and T2-weighted images with high resolution “black blood” spin used to visualize adjacent vessel wall. Matched MRI and TEE cross-sectional aortic images show strong correlation for plaque composition and maximum plaque thickness. In Vivo MRI imaging of Coronary Artery Plaque Difficulties include cardiac and respiratory motion, nonlinear course of coronary arteries, and small size and location of coronary arteries. Inter- and intraobserver variability assessed by intraclass correlation ranged from 0.96-0.99. Wall thickness in human coronaries can be differentiated between normal and 40% stenosis; breathholding can minimize respiratory motion. Fayad and Fuster, Am J Cardiol 2001; 88 (suppl): 42E-45E. Lipid-Lowering by Simvastatin and Reduction in MRI Vessel Wall Area 18 asymptomatic hypercholesterolemic patients studied, with a total of 35 aortic and 25 carotid plaques measured Serial black-blood MRI of aorta and carotid artery performed at baseline, 6, and 12 months At 12 months (but not 6 months), significant reductions in vessel wall thickness and area (8% reduction in aorta and 15% re