Latest developments in magnetic resonance imaging (MRI) hardware and software have significantly improved image acquisition for functional MRI (fMRI) techniques, including resting-state fMRI (rsfMRI). Specifically, with improvements in gradient and radiofrequency coils and advances in pulse sequence designs, functional images with higher spatiotemporal resolution can be achieved. However, while smaller voxel size has the benefit of resolving finer brain structures, it also decreases voxel-wise signal-to-noise ratio (SNR) and, subsequently, temporal SNR (tSNR), which is critical for the sensitivity of fMRI. Although the improved temporal resolution allows more image frames to be collected per unit time, the ability to detect brain activity by using the high spatiotemporal fMRI has not been fully characterized. Here, we aimed to evaluate the effects of spatial smoothing, scan length, sample size, seed size, and location on resting-state functional connectivity (rsFC) and tSNR by using data from the human connectome project. Results from this analysis show an important effect of smoothing on the rsFC strength (correlation values between the seed and the target) as well as on the tSNR. In contrast, while rsFC strength is not affected by sample size, the standard error decreases with the increasing number of participants, therefore improving the detection power for larger samples. Scan length and seed size seem to have a moderate effect on rsFC strength. Finally, seed location has an important impact on rsFC maps, as rsFC strength from cortical seeds seems higher than from sub-cortical seeds. In summary, our findings show that the choice of parameters can be critical for an rsfMRI study.

中文翻译：

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使用高分辨率回波平面成像技术在静止状态功能磁共振成像中影响血氧水平相关信号检测能力的因素。

磁共振成像（MRI）硬件和软件的最新发展显着改善了功能MRI（fMRI）技术（包括静止状态fMRI（rsfMRI））的图像采集。特别地，随着梯度线圈和射频线圈的改进以及脉冲序列设计的进步，可以获得具有更高时空分辨率的功能图像。然而，虽然较小的体素大小具有解决较精细的大脑结构的优势，但它也降低了体素方向的信噪比（SNR），进而降低了时间SNR（tSNR），这对于fMRI的敏感性至关重要。尽管改进的时间分辨率允许每单位时间收集更多的图像帧，但尚未充分表征通过使用高时空fMRI来检测大脑活动的能力。这里，我们旨在通过使用来自人类连接套项目的数据来评估空间平滑，扫描长度，样本大小，种子大小和位置对静止状态功能连接性（rsFC）和tSNR的影响。此分析的结果表明，平滑处理对rsFC强度（种子和目标之间的相关值）以及tSNR具有重要影响。相反，虽然rsFC强度不受样本大小的影响，但标准误差随参与者数量的增加而降低，因此提高了较大样本的检测能力。扫描长度和种子大小似乎对rsFC强度有中等影响。最后，种子位置对rsFC图有重要影响，因为皮质种子的rsFC强度似乎高于皮质下种子的rsFC强度。综上所述，