ULTRAHIGH FIELD TECHNOLOGY FOR FUNCTIONAL IMAGING

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 另见随附的研究进展 在越来越精细的尺度上研究大脑功能结构的愿望一直是一个挑战。 高场强磁共振扫描仪（3特斯拉， 以上）。这项工作的一个主要目标是使功能磁共振成像的仪器分辨率 实验到我们可以探索功能磁共振成像的生物空间限制的水平。作为 目前，功能成像的分辨率为3 mm， 解决皮质带的问题需要一个数量级的改进， 解决下一个较低层次的大脑皮层：层状和柱状 结构.虽然在实现这一目标方面取得了相当大的进展，但一个主要问题是， 对这些形状复杂的3D结构的研究一直是 功能磁共振成像采集 因此，本研究的总体目标是开发3D各向同性 fMRI编码方法，以降低fMRI的空间分辨率，同时避免“法国 油炸”形状的体素，这一直困扰着研究。对于大纵横比体素（通常 在切片方向上最多长10倍）， 被部分体积效应稀释，除了在皮质的小区域， 发生对齐。由于空间分辨率受到固有灵敏度和 有限的空间编码能力，我们将开发高度并行的检测策略， 解决这些问题，并提供真正的三维单次激发体积功能磁共振成像与高各向同性 分辨率我们通过开发一个高灵敏度， 96通道仅接收阵列系统，用于7特斯拉的功能性脑成像。另外 我们将开发模拟模式混合策略，以形成正交线性组合 最大化灵敏度和编码能力的检测元件 具有少量RF通道的系统（例如临床上的32个通道） 系统）。我们开发了单次激发方法，以减少在多个时间不稳定性， 使用高度加速的回波体积和螺旋堆叠轨迹的发射方法。为 最高分辨率的研究，我们将开发缩放EVI利用并行传输 加速空间定制的2D和3D激励。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. See also attached Research Progress The desire to study the structure of brain function at a finer and finer scale has been a major impetus for the development of high field strength MR scanners (3 Tesla and above). A major goal of this effort is to bring the instrumental resolution of the fMRI experiment to the level where we can explore the biological spatial limits of fMRI. As currently practiced with 3mm isotropic resolution, functional imaging cannot even claim to resolve the cortical ribbon. An order of magnitude improvement is needed to readily resolve the next lower level of the cerebral cortex: that of laminar and columnar structures. While considerable progress has been made toward this goal, a major problem plaguing the study of these complexly shaped 3D structures has been the 2D nature of the fMRI acquisition. The overall goal of this study is therefore to develop 3D isotropic fMRI encoding methods to reduce the spatial resolution of fMRI while avoiding the "french fry" shaped voxels which have plagued studies. With large aspect ratio voxels (commonly up to 10 fold longer in the slice direction), desired laminar or columnar structures are diluted by partial volume effects except in small regions of the cortex where a fortuitous alignment occurs. Because spatial resolution is limited by both intrinsic sensitivity and limited spatial encoding capability, we will develop highly parallel detection strategies to address these issues and provide true 3D single-shot volumetric fMRI with high isotropic resolution. We address the sensitivity and encoding issues by developing a high sensitivity 96 channel receive-only array system for functional brain imaging at 7 Tesla. Additionally we will develop analog mode-mixing strategies to form orthogonalized linear combinations of detection elements which maximize the sensitivity and encoding abilitysuitable for systems with a small number of RF channels (such as the 32 channels found on clinical systems). We develop single-shot methods to reduce the temporal instabilities in multi- shot methods using highly accelerated echo-volumnar and stack-of-spirals trajectories. For the highest resolution studies we will develop zoomed EVI utilizing parallel transmission acceleration of spatially tailored 2D and 3D excitations.