Technical Advances for Sodium Magnetic Resonance Imaging

磁共振成像(MRI)是一项核心的现代医疗保健技术，它提供了无与伦比的非侵入性人体图像，反映了各种器官的潜在结构、功能和代谢。在过去的35年里，大学在硬件、软件和成像物理方面的工程进步极大地提高了磁共振成像的质量和能力。常规的临床磁共振成像从水分子中的两个氢核(1H)获取信号，我们主要是由水分子组成的。然而，水磁共振并不能发现所有的异常。我们的解决方案是能够从其他对细胞正常功能和健康至关重要的化学元素中获取MRI图像，如钠(23Na)。值得注意的是，~(23)Na的核磁共振物理比~1H的要复杂得多。在过去的20年里，我们一直在开发钠核磁共振，重点放在大脑(用于中风和多发性硬化症)和软骨(用于骨关节炎)。NSERC提出的发现拨款是为了推动磁共振技术在皮肤中对钠进行成像。饮食中的盐(或钠)对健康起着关键作用，特别是它与高血压(即高血压)有关，这种疾病在加拿大和世界范围内太普遍了。虽然人们可以测量血液样本中的钠水平，但这并不能显示体内不同组织中积累了多少钠。事实上，最近发现皮肤(人体最大的器官)是过量钠的主要储存库。钠核磁共振的国际非侵入性研究(通常是对人的小腿)表明，男性、衰老、高血压、肥胖以及糖尿病、心力衰竭和肾脏疾病等临床疾病的皮肤钠含量会升高。尽管这些结果显示了钠核磁共振的良好用途，但这些研究中使用的成像方法只是借用了1H MRI，其低分辨率图像在钠水平估计中产生了很大的误差。我们的主要研究目标是通过专门为皮肤的钠核磁共振定制的新型工程开发来实现准确的钠浓度，考虑到皮肤如此之薄(仅有1-2毫米厚)，这是具有挑战性的。高分辨率图像(如4K电视屏幕)是必要的，但这需要设计和建造更灵敏的MRI硬件(天线)，以及发明和优化新的钠特定图像采集软件。这些技术进步将由计算机模拟和实验测量来指导。这些最佳的钠核磁共振方法将被用来测量不同年龄范围的健康人(从儿童到老年人)皮肤(小腿)中的钠浓度，包括男性和女性。这将为今后与疾病患者进行比较奠定新的“规范”基础。我们的钠核磁共振进展也将公开和免费地供世界各地的团体使用，以改进他们的研究。

Magnetic Resonance Imaging (MRI) is a core modern health care technology that provides unparalleled non-invasive images of the human body reflecting underlying structure, function, and metabolism in various organs. Over the last 35 years, university-based engineering advances in hardware, software and imaging physics have greatly increased the quality and capability of MRI. Routine clinical MRI acquires signal from the two hydrogen nuclei (1H) in the water molecule, of which we are primarily composed. However, water MRI cannot not detect all abnormalities. Our solution is to enable MRI image acquisition from other chemical elements important for proper cell functioning and health, like sodium (23Na). Note that the MRI physics of 23Na is considerably more complicated than that of 1H. Over the last 20 years, we have been developing sodium MRI with a focus on the brain (for stroke and multiple sclerosis) and cartilage (for osteoarthritis). The proposed NSERC Discovery grant is to advance MRI technology to image sodium in the skin. Salt (or sodium) in diet plays a key role in health, particularly as it relates to the "silent killer" hyper-tension (i.e. high blood pressure), which is far too prevalent in Canada and world-wide. Although one can measure sodium levels in a blood sample, this does not show how much sodium is accumulated in various tissues throughout the body. In fact, it has recently been discovered that skin (the largest organ of the body) is a major reservoir for excess sodium. International non-invasive studies with sodium MRI (usually of the human calf) has shown that skin sodium is elevated in men, aging, hypertension, obesity and clinical conditions such as diabetes, heart failure, and kidney disease. Although these results demonstrate promising utility for sodium MRI, the imaging methods used in these studies were simply borrowed from 1H MRI, and their low resolution images yield large errors in sodium level estimation. Our primary research goal is to enable accurate sodium concentration through novel engineering development specifically tailored for sodium MRI of the skin, which is challenging given how thin it is (only 1-2 mm thick). High-resolution images (like 4K television screens) are necessary, but this requires the design and construction of more sensitive MRI hardware (antennas), as well as inventing and optimizing new sodium-specific image acquisition software. These technology advancements will be guided by both computer simulation and experimental measurements. These optimal sodium MRI methods will be used to measure sodium concentrations in the skin (calf) of healthy individuals over a wide age range (children to the elderly), both males and females. This will establish a new `normative' basis for future comparisons to people with disease. Our sodium MRI advancements will also be made publicly and freely available for use by groups world-wide to improve their studies.