SIGNAL AND NOICE CHARACTERISTICS OF HAHN SE AND GE BOLD FMRI AT 7T IN HUMANS

HAHN SE 和 GE BOLD FMRI 在 7T 下人体中的信号和噪音特征

• 批准号: 7601625
• 负责人: ESSA YACOUB
• 金额: $ 10.63万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7601625
• 关键词: Area; Characteristics; Computer Retrieval of Information on Scientific Projects Database; Data; Functional Magnetic Resonance Imaging; Funding; Grant; Human; Image; Institution; Methods; Noise; Physiological Processes; Research; Research Personnel; Resolution; Resources; Series; Signal Transduction; Source; Standards of Weights and Measures; Time; Tissues; United States National Institutes of Health; magnetic field; millimeter; size

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. At very high magnetic fields, GE BOLD fMRI is expected to contain nonspecific contributions and behave differently than HSE fMRI data. Similarly, the two approaches can conceivably suffer from different contributions to temporal instabilities in a times series that ultimately determine the contrast-to-noise ratio (CNR). We investigate the signal and signal fluctuation characteristics in GE and HSE fMRI data with the imaging parameters separately optimized for each contrast at 7 T. In HSE fMRI, activation-induced fractional signal change (DeltaS/S) decreased rapidly, and the ratio of standard deviations of image-to-image fluctuations due to physiological processes (sigmaPhys) to thermal noise (sigmaTherm) remained constant with increasing voxel volume. In contrast, DeltaS/S as well as volume of activated voxels was virtually independent of voxel size for GE BOLD, and sigma(Phys)/sigmaTherm increased with increasing voxel size. The ratio of BOLD signal changes (GE/HSE) was much closer to 1 in tissue areas compared to vessel areas. These observations led to the conclusions that the spatial extent of the activation-induced DeltaS/S was much broader in the GE data, and that the physiological processes that give rise to the temporal fluctuations lost coherence over millimeter distances in HSE compared to GE fMRI data. While further studies are needed to characterize it fully, sigmaPhys in HSE data was clearly different than in GE data. It was concluded that HSE imaging yields a significantly reduced amount of nonspecific signals compared to GE imaging, and, would be the method of choice (over GE) for high-resolution applications in humans.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 在非常高的磁场下，GE Bold fMRI有望包含非特异性贡献，并且与HSE fMRI数据的行为不同。同样，这两种方法可以想象，这两种方法对时间序列的时间不稳定性造成了不同的贡献，最终决定了对比度与噪声比率（CNR）。 We investigate the signal and signal fluctuation characteristics in GE and HSE fMRI data with the imaging parameters separately optimized for each contrast at 7 T. In HSE fMRI, activation-induced fractional signal change (DeltaS/S) decreased rapidly, and the ratio of standard deviations of image-to-image fluctuations due to physiological processes (sigmaPhys) to thermal noise (sigmaTherm) remained constant with增加体素体积。相比之下，Deltas/s以及活化体素的体积实际上与GE Bold的体素大小无关，而Sigma（Phys）/Sigmatherm随着体素尺寸的增加而增加。与血管区域相比，在组织区域，大胆信号变化的比率接近1个。这些观察结果得出了这样的结论：与GE FMRI数据相比，激活诱导的deltas/s的空间范围在GE数据中更广泛，并且导致时间波动在HSE中的相干距离上失去了相干性。尽管需要进一步的研究来充分表征它，但HSE数据中的Sigmaphys显然与GE数据中的Sigmaphys有所不同。结论是，与GE成像相比，HSE成像可显着减少非特异性信号，并且是人类高分辨率应用的首选方法（超过GE）。