Development of New Methods for Quantitative MRI

磁共振成像（MRI）对于检查身体中的软组织非常有用，并且在能力上仍在快速发展，并且在使用中不断增加。MRI的局限性之一是它往往不能提供精确的组织测量，而是通过比较不同区域的信号来进行相对测量。 如果能够为MRI开发快速和精确的定量组织测量，它可以进一步提高其提供精确信息的能力，这对医学成像和工业用途都是有价值的。 我们的实验室专注于通过利用每种形式的图像对比度的MRI物理学来产生新的MRI方法。我们的长期目标是不断开发新的方法，增加MRI的价值，并基于对MRI物理学及其与人体组织特性的关系的理解。该研究计划将开发新的定量MRI方法，重点关注三种独特的定量技术。这三个感兴趣的领域是MRI应用的新兴领域，需要进一步发展才能成为实用工具。第一个领域试图从最小量的扫描中确定多个定量MRI参数，并且被称为MRI指纹识别。类似于侦探使用模式识别来确定物理指纹，我们使用MRI进化的模式识别来一次确定多个参数。我们将在这一领域做出独特的贡献，利用标准MRI序列，这将使立即纳入标准MRI协议，而不需要冗长的额外扫描。这项工作建立在我们最近在单参数定量弛豫映射方面的工作基础上。第二个区域试图测量磁场，然后确定实际的磁化率分布。这个领域被称为定量易感性映射（QSM）。磁化率提供了一种独特的图像对比度形式，但QSM方法仍在不断发展。 我们将致力于提高QSM采集和处理方法的速度、鲁棒性和使用，以成像不可见的物体、血管、铁、钙和髓鞘。第三个区域可以间接成像大脑中的代谢物，称为化学交换饱和转移（CEST）。该方法提供了一种观察大脑化学特性的方法，包括神经递质含量和大脑酸度。 我们将努力进一步验证这些方法相比，光谱技术，也使用MRI。这项工作对我们的实验室来说是新的。*这三个领域的进展将包括新的后处理方法，新的成像序列，新的方法验证和人类定量MRI的新应用。这些进展将有助于将这些新兴的MRI方法转变为定量MRI的可行工具，并将为下一代成像科学家提供理想的培训环境。

Magnetic Resonance Imaging (MRI) is very useful for examining soft tissue in the body and is still rapidly evolving in capability and increasing in use. One of the limitations of MRI is it tends to not provide exact tissue measurements, instead making relative measurements by comparing the signal in different areas. If fast and exact quantitative tissue measures could be developed for MRI, it could further its ability to offer precise information which would be valuable for medical imaging and industrial uses. Our laboratory specializes in the generation of new MRI methods by exploiting the MRI physics underlying each form of image contrast. Our long term goal is the continual development of novel methods that increase the value of MRI and are based on understanding MRI physics and its relationship to human tissue properties. This research proposal will develop new means of performing quantitative MRI, focusing on three unique quantitative techniques. The three areas of interest are emerging areas of MRI application that require further evolution to become practical tools.******The first area attempts to determine multiple quantitative MRI parameters from a minimal amount of scanning and is known as MRI fingerprinting. Similar to a detective's use of pattern recognition to determine a physical fingerprint, we use pattern recognition of MRI evolution to determine multiple parameters at once. We will develop unique contributions in this area that make use of standard MRI sequences, which would enable immediate incorporation into standard MRI protocols, without needing lengthy additional scans. This work builds on our recent work in single parameter quantitative relaxation mapping.******The second area attempts to measure the magnetic field and then determine the actual magnetic susceptibility distribution. This area is known as Quantitative Susceptibility Mapping (QSM). The magnetic susceptibility provides a unique form of image contrast but the QSM methods are still evolving. We will work towards improving the speed, robustness and use of QSM acquisitions and processing methods to image invisible objects, blood vessels, iron, calcium and myelin.******The third area enables indirect imaging of metabolites in the brain and is known as Chemical Exchange Saturation Transfer (CEST). The method provides a means to look at chemical properties of the brain including neurotransmitter content and brain acidity. We will work to further validate these methods in comparison to spectroscopic techniques that also use MRI. This work is new to our laboratory.******The advances in all three areas will consist of new post-processing approaches, new imaging sequences, new validations of methods and new applications for human quantitative MRI. These advances will help turn these emerging MRI methods into viable tools for quantitative MRI and will provide ideal training environments for the next generation of imaging scientists.