Development and Validation of Cardiovascular MR Imaging and Spectroscopy at 7 Tesla

磁共振成像（MRI）使我们能够对人体内部进行无创成像。在过去的5-10年里，这项技术在临床心脏成像中发挥了不可估量的作用。核磁共振扫描仪在1.5特斯拉(T)的磁场强度下工作。我们率先使用3T扫描仪，最近购买了市售的最高场强人体扫描仪（7特斯拉）。在高场强下成像会产生更多的信号，从而更快地获得图像，或者具有更高的空间分辨率。我们将在7T时开发的区域是那些受1.5和3T的低信噪比（信噪比）限制的区域。其中包括冠状动脉成像，血液氧合成像，以及使用磁共振波谱测量人类心脏中富含能量的代谢物。冠状动脉成像尤其重要，因为这些血管对心脏供血至关重要（阻塞会导致心脏病发作）。7T的高信噪比将以比以前MRI更高的分辨率显示这些血管的血液和壁，使我们能够看到小斑块和细微的损伤。心脏的代谢状况是另一个重要的研究领域，我们牛津大学在这方面处于世界领先地位。一种叫做磁共振波谱的技术揭示了心脏的生物化学。磷酸肌酸和三磷酸腺苷是提供能量的重要代谢物，它们的水平甚至可以在功能改变变得明显之前给出损伤的指示。在7T时，更高的空间分辨率使MRS能够检查心脏的小区域，相当于目前临床检查所需要的（在较低场强时不可能）。其他项目将在这些方法的基础上研究氧气供应、纤维疤痕组织的程度和心脏小血管的血液供应。在临床上，这些发展有可能将心脏代谢、氧合和冠状动脉斑块生物学的磁共振成像从一个小众研究工具转变为一种主流诊断手段，可以将患者作为个体进行治疗，使医生能够监测疾病的进展或对治疗的反应。这些技术将大大有助于改善心血管健康和减轻心血管疾病的负担。我们的计划是非常新颖的，我们将是英国第一家，也是世界上开发心脏磁共振成像的精英团队之一。

Magnetic Resonance Imaging (MRI) allows us to image the inside of the human body non-invasively. Pioneered in the brain, this technique has become invaluable over the last 5-10 years for imaging the heart in the clinic. MRI scanners operate at a magnetic field strength of 1.5Tesla (T). We have pioneered the use of 3T scanners, and have most recently purchased the highest field strength commercially available human scanner (7Tesla). Imaging at higher field strength results in more signal, and thus, the images are obtained quicker, or with higher spatial resolution. The areas that we will develop at 7T are those that are limited by low SNR (signal-to-noise ratio) at 1.5 and 3T. These include imaging the coronary arteries, imaging the oxygenation of the blood, and using magnetic resonance spectroscopy to measure the energy-rich metabolites in the human heart. Coronary artery imaging is particularly important as these vessels are critical to supplying blood to the heart (blockages cause heart attack). The higher SNR of 7T will show the blood and walls of these vessels at higher resolution than has previously been possible with MRI enabling us to visualise small plaques and subtle damage. The metabolic condition of the heart is another important area of research where we in Oxford are world leaders. A technique called magnetic resonance spectroscopy reveals the biochemistry of the heart. Levels of phosphocreatine and adenosine triphosphate, which are essential energy-providing metabolites, can give an indication of damage even before functional changes become apparent. At 7T, the higher spatial resolution enables the MRS examination of small regions in the heart, equivalent to those presently required in a clinical examination (impossible at lower field strength). Additional projects will build on these methods to look at oxygen supply, the degree of fibrous scar tissue, and the blood supply from small vessels in the heart. Clinically these developments have the potential to transform MR imaging of cardiac metabolism, oxygenation, and coronary plaque biology from a niche research tool into a mainstream diagnostic measure that can treat the patient as an individual, enabling doctors to monitor the progress of a disease or the response to therapy over time. These techniques would contribute significantly to improving cardiovascular health and to relieving the burden of cardiovascular disease. Our plans are highly novel, and we would be the first site in the UK, and one of an elite group world-wide developing cardiac MR at 7T.