New Tools for Understanding White Matter Disease using Diffusion MRI

使用扩散磁共振了解白质疾病的新工具磁共振成像(MRI)是一项快速发展的技术，用于对人体进行成像，通常不需要任何侵入性程序，如注射或暴露在辐射中。磁共振成像能够为我们提供人体内部的高细节图像，因此可以告诉我们许多关于疾病的存在或发展的信息。磁共振成像的一项最新进展被称为扩散磁共振成像，它观察体内水颗粒的随机运动。在拍摄大脑图像时，这一点尤其有趣，因为水往往更多地沿着大脑内部连接的方向移动。大脑中的这些连接被称为白质，对保持大脑正常工作至关重要。它们是将信息从大脑的一个部分传递到另一个部分的路径，如果它们受损，大脑甚至无法执行简单的任务。扩散磁共振成像的独特之处在于它能够研究这些路径，基于水是如何沿着它们流动的。有许多疾病会影响大脑中的白质，它可能很难准确地理解疾病是如何攻击白质的，预测疾病将如何在特定的人身上发展，并决定对该人进行正确的治疗。幸运的是，因为弥散磁共振对脑白质的变化很敏感，所以它是发现这些疾病的一个很好的方法。例如，如果疾病破坏了通路，水就会停止沿通路流动，或者从通路中渗出，扩散核磁共振就能看到这一点。一个突出的大问题是每个人的大脑都是独一无二的：每个大脑的形状都略有不同，它们的内部连接也不同，所以一个人的大脑图像不会与另一个人的大脑在文本上对齐。这使得很难对一组人(比如说，疾病患者)和另一组人(健康人)进行简单的比较。在这个项目中，我们希望开发新的数学技术来变形扩散图像，使一个人的大脑与另一个人的大脑相匹配。这是非常困难的，特别是对于大脑中一些人与人之间差异巨大的部分。然而，如果我们能在数学研究中取得成功，并设法将不同人的大脑图像匹配在一起，我们就可以比较不同人群在大脑中的信息通路。如果我们能做到这一点，那么我们就可以开始了解特殊疾病是如何随着时间的推移导致大脑退化的。对于多发性硬化症这样的疾病，我们可以用它来评估不同的药物治疗，以帮助加快新的和更好的药物的开发。在中风患者中，我们可以观察白质损伤的模式，并可能准确地找出哪种物理治疗可以帮助他们最有效地恢复。对于过早出生的婴儿，我们可以使用扩散成像来找出哪些保护性治疗在帮助婴儿正常发育方面效果最好。

New Tools for Understanding White Matter Disease using Diffusion MRIMagnetic resonance imaging (MRI) is a rapidly-developing technologyfor imaging humans that normally does not need any invasive procedures such as injections or exposure to radiation. MRI is able togive us highly-detailed images of the inside of the body, and cantherefore tell us a lot about the presence or development of disease.One recent advance in MRI is known as diffusion MRI , which looks atthe random motion of water particles in the body. This is particularlyinteresting when taking images of the brain, because water tends tomove more along the directions of the connections inside thebrain. These connections in the brain, known as white matter , arecrucial to keeping the brain working correctly. They are the pathwaysthat carry information from one part of the brain to another, and ifthey are damaged, the brain cannot perform even simple tasks.Diffusion MRI is unique in its ability to study these pathways, basedon how water flows along them.There are many diseases that affect the white matter in the brain, andit can be very hard to understand exactly how the disease attacks thewhite matter, to predict how the disease will develop in a particularperson, and to decide what the right treatment is for thatperson. Fortunately, because diffusion MRI is sensitive to changes inwhite matter, it is an excellent way of finding out about thesediseases. For example, if the disease is breaking down the pathways,water stops moving along them, or leaks out of them, and diffusion MRIcan see this.One of the big outstanding problems is that everyone's brain isunique: every brain is a slightly different shape, and their internalwiring is also different, so a picture of one person's brain doesn'texactly line up with another person's brain. This makes it difficultto make simple comparisons of one set of people (say, patients with adisease) with another (healthy people). In this project we hope todevelop new mathematical techniques for deforming diffusion images sothat one person's brain matches another's. This is very difficult toget exactly right, particularly for some parts of the brain that varyenormously from person to person. However, if we can succeed in ourmathematical research, and manage to match the brain images fromdifferent people together, we can then compare the informationpathways in the brain for different groups of people.If we can achieve this, then we can start to learn about how aparticular disease causes the brain to degenerate over time. Fordiseases like multiple sclerosis, we can use this to evaluatedifferent drug treatments, to help speed up the developments of newand better drugs. In people who have suffered a stroke, we can look atthe pattern of white matter damage, and possibly work out exactly whatkind of physiotherapy treatment will help them recover mosteffectively. In babies who have been born much too early, we can usethe diffusion imaging to find out which protective treatments workbest at helping the babies develop normally.