ULTRAHIGH FIELD TECHNOLOGY FOR FUNCTIONAL IMAGING

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 另请参阅随附的研究进展 在越来越精细的范围内研究大脑功能结构的愿望一直是一种 高场强磁共振扫描仪发展的主要推动力(3特斯拉和 上图)。这项工作的一个主要目标是将功能磁共振成像的仪器分辨率 实验到我们可以探索fMRI的生物空间极限的水平。AS 目前使用的是3 mm各向同性分辨率，功能成像甚至不能声称 解析皮质功能区。需要一个数量级的改进才能轻易地 分解大脑皮层的下一个较低水平：层状和柱状 结构。虽然朝着这一目标取得了相当大的进展，但一个主要问题是 这些形状复杂的3D结构的2D性质一直困扰着对它们的研究 功能磁共振成像的收购。因此，本研究的总体目标是开发3D各向同性 降低fMRI空间分辨率的fMRI编码方法 Fry“形体素一直困扰着研究。大长宽比体素(通常 在切片方向上长达10倍)，所需的层状或柱状结构 被部分体积效应稀释，但在皮质的小区域，偶然的 就会发生对齐。因为空间分辨率既受内在敏感性的限制，又受 有限的空间编码能力，我们将开发高度并行的检测策略来 解决这些问题并提供具有高各向同性的真3D单次激发体积功能磁共振成像 决议。我们通过开发高敏感度解决敏感度和编码问题 96通道仅接收阵列系统，用于7特斯拉的脑功能成像。另外 我们将开发模拟模式混合策略以形成正交化的线性组合 最大限度地提高灵敏度和编码能力的检测元件 具有少量RF通道的系统(例如在临床上发现的32个通道 系统)。我们发展了单次激发的方法来减少多脉冲的时间不稳定性。 使用高速回波体积和螺旋线堆叠轨迹的拍摄方法。为 最高分辨率的研究我们将开发利用并行传输的变焦EVI 空间定制的2D和3D激励的加速。

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.