OPTIMAL COMBINATION OF SPIRAL-IN/OUT BOLD SIGNALS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。采用螺旋入/出技术的采集结果在螺旋入和螺旋出轨迹中分别获得两个独立的图像时间序列。在均匀的脑区，这两种成分具有可比较的信号和BOLD对比度，可以平均，但在受敏感性影响的区域，两幅图像中的信号和噪声可能不同，其他组合方法可能更有效。在这里，我们比较了几种加权方案在全脑和前额叶皮层的信号和激活对比恢复，使用3T扫描的言语工作记忆（7名受试者）和屏气任务（6名受试者）。研究发现，基于分别从螺旋入和螺旋出图像导出的激活图的统计加权组合提供的激活体积比第二选择信号加权组合和单独的螺旋出采集增加，并且简单的平均不如信号加权组合。

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. Acquisitions with the spiral-in/out technique result in two separate image timeseries obtained during the spiral-in and spiral-out trajectory, respectively. In uniform brain regions the two components have comparable signal and BOLD contrast and can be averaged, but in regions compromised by susceptibility effects where both signal and noise can differ in the two images other combination methods may be more effective. Here, several weighting schemes are compared for signal and activation contrast recovery in whole brain and prefrontal cortex using verbal working memory (7 subjects) and breath-holding tasks (6 subjects) scanned at 3T. It is found that a statistically-weighted combination based upon activation maps derived separately from the spiral¿in and spiral-out images provides activation volumes with increases over second-choice signal-weighted combination and over spiral-out acquisition alone, and that simple averaging is inferior to signal-weighted combination.