Novel Ultrashort Echo Time Sequences for Brain MRI

用于脑 MRI 的新型超短回波时间序列

• 批准号: 9112765
• 负责人: Peder Eric Zufall Larson
• 金额: $ 19.81万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9112765
• 关键词: Acceleration; Age; Alzheimer' s Disease; Axon; Biological Neural Networks; Birth; Brain; Chemicals; Clinical; Data; Demyelinating Diseases; Demyelinations; Detection; Development; Diagnosis; Diffusion; Disease; Evaluation; Evaluation Studies; Future; Human; Image; Investigation; Lesion; Life; Magnetic Resonance Imaging; Measurement; Measures; Membrane; Methods; Modeling; Monitor; Multiple Sclerosis; Myelin; Neurodegenerative Disorders; Neurons; Operative Surgical Procedures; Patients; Phospholipids; Physiologic pulse; Play; Property; Protocols documentation; Protons; Recruitment Activity; Relaxation; Role; Scanning; Signal Transduction; Source; Structure; Time; Water; age group; base; contrast imaging; data acquisition; density; dysmyelination; gray matter; healthy volunteer; imaging biomarker; imaging modality; improved; in vivo; in vivo imaging; leukodystrophy; method development; multiple sclerosis patient; myelination; nervous system disorder; neurotransmission; non-invasive imaging; normal aging; novel; programs; public health relevance; rapid technique; reconstruction; remyelination; research clinical testing; specific biomarkers; temporal measurement; treatment response; white matter

 DESCRIPTION (provided by applicant): Myelin plays a critical role in neuronal signal conduction across the brain as an insulating layer of phospholipid membranes around axons. Myelin formation begins shortly after birth, continuing well into the 5th decade of life in humans, and is the basis for long range neural networks. The degree of myelination and its structure is also a key feature of many neurological disorders, especially demyelinating diseases such as multiple sclerosis, leukodystrophies, and neruodegeneration. In this project, we propose to develop a new MRI method for non-invasive imaging of myelin. It is based on a previously unexplored source of myelin contrast that has been shown in recent ex vivo studies to be originating from protons in the myelin phospholipid membranes. This source of contrast is not exploited by any current MRI methods for imaging myelin because it has a rapid decay rate (ultrashort-T2), meaning its signal has decayed by the time data is acquired using conventional approaches. We will use methods based on ultra- short echo time (UTE) MRI that leverage specialized excitations, acquisitions, and reconstructions in order to detect such rapidly decaying components. While current MRI methods for imaging myelin, including magnetization transfer, diffusion, and myelin water fractions, rely on detection of signal from protons in water, this new source of contrast comes directly from protons in the myelin phospholipid membranes. We believe that this could provide more specific imaging of myelin and thus could provide a more specific imaging biomarker of myelination, demyelination, dysmyelination, and remyelination. As a more specific biomarker, imaging this membrane component could improving our understanding of brain development as well as be applied for diagnosis, localization, surgical planning, and monitoring response to treatment in many disorders. As this source of contrast is largely unexplored, we first propose to characterize its MRI properties in human studies, both in healthy volunteers of various ages as well as multiple sclerosis patients with previously identified demyelinating lesions. This will provide an initial evaluation of this largely unexplored source of contrast in normal appearing gray and white matter as well as in demyelinated lesions. Since these complete characterization studies will require long scan times, we will also develop SNR and contrast efficient imaging methods based on UTE MRI in order to enable widespread measurements of this source of contrast in future clinical evaluation studies.

 描述（由适用提供）：髓鞘在整个大脑的神经元信号传导中起关键作用，作为轴突周围磷脂膜的绝缘层。髓鞘形成在出生后不久开始，一直持续到人类生活的第五个十年， 并且是远距离神经元网络的基础。髓鞘及其结构的程度也是许多神经系统疾病的关键特征，尤其是脱髓鞘性疾病，例如多发性硬化症，白细胞营养不良和neruodegeneration。在这个项目中，我们建议开发一种新的MRI方法，用于髓磷脂的非侵入性成像。它基于以前出乎意料的髓磷脂对比来源，在最近的离体研究中已显示出源自髓磷脂磷脂机制中的质子。任何当前的MRI方法都不会探索这种对比度的来源，因为它具有快速的衰减速率（Ultrashort-T2），这意味着它的信号已通过使用常规方法获取时间数据衰减。我们将使用基于超短回声时间（UTE）MRI的方法来利用专门的兴奋，采集和重建来检测这种快速衰减的组件。而当前用于成像髓磷脂的MRI方法，包括磁化转移，扩散和髓磷脂水分，但依赖于从水中质子中检测信号，但 这种新的对比来源直接来自髓磷脂磷脂膜中的质子。我们认为，这可以提供更具体的髓磷脂成像，因此可以提供更具体的成像生物标志物，髓鞘形成，脱髓质和透明度。作为更具体的生物标志物，该膜成分成像可以提高我们对大脑发育的理解，并适用于诊断，定位，手术计划以及监测许多疾病治疗的反应。由于这种对比的来源在很大程度上是出乎意料的，因此我们首先建议在人类研究中表征其MRI特性，包括各个年龄的健康志愿者以及先前确定的脱髓鞘病变的多发性硬化症患者。这将提供对正常出现的灰色和白质以及脱髓鞘病变的正常对比来源的初步评估。研究将需要长时间的扫描时间，我们还将根据UTE MRI开发SNR和对比度有效的成像方法，以便在未来的临床评估研究中对这种对比来源进行宽度测量。