MRI OF THE CENTRAL CARADIOVASCULAR SYSTEM

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The capabilities of Magnetic Resonance (MR) imaging of the central car- diovascular system (i.e., heart, great arteries and veins, small vessel networks in the thorax) have been advanced in recent years from primarily a definition of the anatomy of the walls of the cardiac chambers and the large vessels to the evaluation of physiologic and hemodynamic parameters using dynamic imaging and blood-signal-enhancing ("bright blood") sequences. Evaluation of the central cardiovascular system in normal and diseased states using MR imaging, however, remains limited due to nonuniformity of the blood signal in the various intracardiac/intravascular blood pools on dynamic display, difficulties with displaying the complex branching patterns of the large vasculature systems in the thorax, and present inability to provide the resolution, complex display, and motion compensation required for imaging small vessel networks, such as the coronary artery system. Our primary goal in this proposed research is to overcome these limitations by means of technical development and application. Technical development which is planned involves work in the following areas: (1) reduction of phase errors; (2) reduction of in-flow artifact; (3) reduction of periodic motion artifact; and (4) improvement of image resolution and contrast. High resolution, high signal-to-noise MR imaging in the presence of physiologic cardiac and respiratory motion is sought. The application of these techniques is concerned with the following: (5) dynamic display of intracardiac blood pools; (6) static display of the major thoracic arterial systems; and (7) display of small vessel networks in the thorax, especially the coronary arteries and their branches. This clinical aspect of the project will be concerned primarily with the assessment of the capability of our techniques to produce images resembling the corresponding angiographic "gold standards". This aspect will be pursued primarily using volunteer controls and patients. The outcome of this effort would be the improved detection with imaging of the presence or absence of a large range of central cardiovascular diseases, and the improved description of the anatomic and functional aspects of the disease.