Multiplexed Multiband MR at 7T: Studies of mild Traumatic Brain Injury

7T 多重多波段 MR：轻度创伤性脑损伤的研究

基本信息

批准号：
8893176
负责人：
Hoby P Hetherington
金额：
$ 49.62万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-09-01 至 2017-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8893176
关键词：
Address Afghanistan Blast Cell Blast Injuries Brain Brain Concussion Brain imaging Brain region Choline Clinical Clinical Management Clinical assessments Cognitive Cognitive deficits Data Collection Deposition Diagnosis Evaluation Failure Functional Magnetic Resonance Imaging Functional disorder Goals Head Hippocampus (Brain)Human Image Impairment Injury Iraq Left Link Magnetic Resonance Imaging Malingering Metabolic Methods Motivation Neurologic Neurologic Deficit Output Patient Self-Report Performance Phase Physiologic pulse Recording of previous events Reporting Reproducibility Resolution Severities Slice Speed Sports Surface System Testing Time Translating Veterans War Work cognitive performance cognitive testing disability disability payment experience imaging modality improved magnetic resonance spectroscopic imaging mild traumatic brain injury rehabilitation management transmission process

项目摘要

DESCRIPTION (provided by applicant): Although 7T systems have been available since the late 1990s, progress for brain imaging at 7T has been slowed by the transmit performance of conventional head coils (i.e. a large transmit only volume coil with a receive only phased array). At 7T large single drive transmit head volume coils suffer from poor homogeneity (40-50%) and low efficiency and limited SNR. The use of receive only phased arrays within these coils significantly enhances SNR and enables parallel reception but does not improve the transmit performance. These limitations can be addressed by the use of transceiver arrays which provide both independent transmission and reception. Transceiver arrays using parallel transmission and/or RF shimming offer improved homogeneity, spatially tailored excitation, gradient independent outer volume suppression and reduced SAR. To date, the number of coils in these transceiver arrays has been limited to the number of independent transmit channels (typically 8) and the small size of these coils required to maintain optimal SNR. To address these limitations we will: i) eliminate the need for equal numbers of transmit and receive channels for the multiple row transceiver arrays by developing new pulse sequence methods which utilize RF multiplexing to drive multi-row transceiver arrays and reduce power deposition; ii) enhance the efficiency of multi-plane MRSI data collection and reduce SAR by developing multi-band acquisition MRSI acquisitions. To evaluate the methods developed we will study veterans with mild traumatic brain injury (mTBI) arising from blast exposure. It has become clear that veterans exposed to mTBI from blast injury display delayed neurological deficits, often without clear imaging correlates. In the absence of objective confirmatory imaging evidence, poor performance on cognitive evaluations can be attributed to poor subject effort, complicating diagnosis, management, rehabilitation and raising questions as to validity of the reported disability. Our recent work has demonstrated that in veterans with blast related mTBI, significant metabolic alterations are seen in the hippocampi which correlate with assessments of effort and cognitive performance. Using the enhanced spatial coverage afforded by the methods developed we will evaluate the hypothesis that in veterans exposed to blast related mTBI, the presence and severity of cognitive and neurologic deficits are correlated with metabolic abnormalities/impairments in the functionally linked brain regions.

描述（由申请人提供）：虽然 7T 系统自 20 世纪 90 年代末以来就已经可用，但由于传统头部线圈（即带有仅接收相控阵的大型仅传输卷线圈）的传输性能，7T 脑成像的进展已经放缓。。在 7T 大型单驱动发射头体积线圈中，均匀性差（40-50%），效率低，信噪比有限。在这些线圈内使用仅接收相控阵可以显着提高信噪比并实现并行接收，但不会提高发射性能。这些限制可以通过使用提供独立传输和接收的收发器阵列来解决。使用并行传输和/或射频匀场的收发器阵列可提供改进的均匀性、空间定制激励、梯度独立的外部体积抑制和降低的 SAR。迄今为止，这些收发器阵列中的线圈数量仅限于独立传输通道的数量（通常为 8 个）以及维持最佳 SNR 所需的小尺寸线圈。为了解决这些限制，我们将： i) 通过开发新的脉冲序列方法，利用射频复用来驱动多行收发器阵列并减少功率沉积，从而消除多行收发器阵列对相同数量的发送和接收通道的需求； ii) 通过开发多频段采集 MRSI 采集，提高多平面 MRSI 数据采集效率并降低 SAR。为了评估所开发的方法，我们将对因爆炸暴露而遭受轻度创伤性脑损伤 (mTBI) 的退伍军人进行研究。很明显，因爆炸损伤而暴露于 mTBI 的退伍军人表现出迟发性神经功能缺损，通常没有清晰的影像学相关性。在缺乏客观的影像学验证证据的情况下，认知评估表现不佳可归因于主体努力不足，使诊断、管理、康复变得复杂，并对所报告的残疾的有效性提出了疑问。我们最近的工作表明，在患有爆炸相关 mTBI 的退伍军人中，海马体中出现了显着的代谢变化，这与努力和认知表现的评估相关。利用所开发的方法提供的增强的空间覆盖范围，我们将评估以下假设：在暴露于爆炸相关 mTBI 的退伍军人中，认知和神经功能缺陷的存在和严重程度与功能相关大脑区域的代谢异常/损伤相关。