Improved Functional MRI Using Balanced SSFP and Parallel Transmission

描述(申请人提供)：该项目的目标是将一种新的基于MRI的成像方法应用于脑功能成像，目的是获得更高的图像质量，提高空间分辨率，并潜在地改善激活信号。传统的功能磁共振成像(FMRI)方法采用T2加权梯度回波(GRE)序列，存在图像模糊、失真、激活对比度噪声比(CNR)低等问题。平衡稳态自由进动(BSSFP)功能磁共振成像有可能解决这些缺点，但引入了其他来源的伪影和信号损失，并仍处于发展阶段。使用新颖的bSSFP脉冲序列设计和并行射频传输，我们已经证明了稳健的、无伪影的bSSFP成像是可能的，前提是成像视场(FOV)的B0不均匀足够平滑。为了评估我们的方法在大脑功能成像中的适用性，我们将测量志愿者的全脑B0模式，并使用观察值来优化脉冲序列设计。该方法将应用于通带bSSFP功能磁共振成像研究，并与传统的GRE BOLD功能磁共振成像进行比较。如果成功，该项目将产生一种图像采集序列，它与传统的GRE功能磁共振成像一样灵活和强大，但具有更少的失真和模糊，可能更准确和可靠的激活图，以及潜在的卓越对比度特性。 与公众健康相关：在这个项目中，我们将为功能脑成像实验开发新的和改进的成像技术。与目前的功能磁共振成像方法相比，新方法将产生细节更精细的大脑图像。

DESCRIPTION (provided by applicant): The goal of this project is to apply a novel MRI-based imaging method to functional brain mapping, with the aim of achieving superior image quality, improved spatial resolution, and potentially improved activation signal. Conventional functional MRI (fMRI) imaging methods employ T2-weighted gradient-recalled echo (GRE) sequences, and suffer from image blur, distortion, and low activation contrast-to-noise ratio (CNR). Balanced steady-state free precession (bSSFP) fMRI has the potential to address these shortcomings, but introduces other sources of artifact and signal loss and has remained at the developmental stage. Using novel bSSFP pulse sequence design and parallel RF transmission, we have shown that robust, artifact-free bSSFP imaging is possible, provided that the B0 inhomogeneity across the imaging field-of-view (FOV) is sufficiently smooth. To assess the applicability of our method to functional imaging in the brain, we will measure whole-brain B0 patterns in volunteers, and use the observed values to optimize the pulse sequence design. The proposed method will be applied to passband bSSFP fMRI studies, and will be compared with conventional GRE BOLD fMRI. If successful, this project will produce an image acquisition sequence that is as flexible and robust as conventional GRE fMRI, but with reduced distortion and blur, potentially more accurate and reliable activation maps, and potentially superior contrast properties. PUBLIC HEALTH RELEVANCE: In this project, we will develop new and improved imaging technology for functional brain mapping experiments. Com- pared with current functional MRI methods, the new method will produce images of the brain with much finer detail.