The aim of this research project is to develop a noninvasive coronary artery imaging method using magnetic resonance (MR) to enable the detection of coronary artery lesions in humans. Given the prevalence of coronary artery disease, such noninvasive imaging has long been one of the most sought-after goals in medical imaging. Visualization of coronary arteries is challenging because the vessels are small, moving, and surrounded by muscle, fat, and other blood. Over the past ten years, advances in MR imaging technology (hardware and pulse sequences) have led to steady progress in coronary magnetic resonance angiography (MRA). However, further progress is needed to establish it as a useful clinical method. Because of MR's flexibility, significant opportunities exist to improve the effectiveness of current methods. A successful approach must integrate solutions to achieve the proper vessel contrast, spatial resolution, and signal-to-noise ratio (SNR), while compensating for cardiac motion and respiration. In addition, these features must be achieved with a scanning protocol that is efficient and easy to use. In this competing renewal application, the research plan is to develop, implement, and evaluate coronary MRA methods that address these issues. This plan will include new studies of fast spiral scanning, improved respiratory compensation, contrast-preparation methods, and real-time interactive MR imaging to achieve improved vessel contrast, higher spatial resolution and SNR, and more efficient scanning protocols. This project will build on the wide range of technology developed as a result of this research program and which have demonstrated considerable potential for effective coronary MRA. Several engineering studies will be conducted to optimize the coronary MRA methods. Clinical studies will include a comparison of the optimized method with conventional x-ray angiography in patients with suspected coronary artery disease. Overall, this project will combine a proven technical program with constant clinical feedback to facilitate the improvement and refinement of the methods.