CONTRAST-ENHANCED, HIGH-RESOLUTION MRI OF CORONARIES

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Coronary artery disease is the leading cause of death in the United States. The overall objective of the proposed project is to develop, optimize, and validate a high resolution magnetic resonance (MR) imaging protocol to evaluate coronary artery disease noninvasively. The long-term goal is to provide a noninvasive screening test for coronary artery disease. This test could potentially be combined with other hemodynamic, functional, and metabolic studies available from MRI to form a comprehensive examination of coronary artery disease for improved patient care and cost savings. The specific goal of the project is to be able to image proximal coronary arteries within several breath-holds and with a spatial resolution of 0.5 mm3 using a three-dimensional data acquisition method. For this purpose, fast MR imaging techniques (segmented echo-planar imaging and quarter Fourier reconstruction) will be developed to improve the speed and resolution of coronary artery images. The utility of newly developed intravascular MR contrast agents will be evaluated for coronary artery imaging and the imaging techniques will be optimized for maximal blood signal-to-noise ratio and blood/background contrast-to-noise ratio. Real-time slice-following and retrospective motion correction schemes will be developed to register data acquired from different breath-holds. Rigorous theoretical simulations, phantom studies, normal volunteer studies, and animal studies will be performed to validate each aspect of the imaging protocol. Particularly, the optimized protocol will be tested in a pig model with coronary artery stenosis created by balloon overstretch injury of arteries and atherogenic diet. Finally, the optimized and validated imaging protocol will be used to image patients with coronary artery disease to define its capability to detect coronary artery disease in a real clinical setting in comparison with conventional x-ray angiography. The end point of the project is to have a robust, clinically viable, rigorously validated protocol for imaging the proximal coronary arteries.