Development of Dual-Polarity GRAPPA for Echo Planar Imaging Methods

神经精神疾病的诊断和治疗关键取决于其特征 神经功能和大脑中的血液流动。使用EPI序列的功能磁共振是 目前用于研究脑功能的成像标准。 在7特斯拉的超高强度下，脑功能和脑血流灌注的研究受到以下限制 EPI数据采集过程中固有的成像伪影。一个占主导地位的艺术品是 EPI重影，表现为偏离原始源的测量信号的副本 地点。在某些情况下，这些移位的副本可能会显示为可能发生变化的涟漪伪像 在成像过程中，将时间不稳定性引入数据。这些文物 磁场强度越高，尤其是成像结构时，表现得越明显 在大脑深处。 我们最近提出了一种新的方法，双极性格拉帕(DPG)，它有效地模拟了 并纠正造成鬼影和波纹伪影的数据采样不一致。这项建议 寻求将这种新方法应用于出现这些伪像的临床应用，包括 功能、灌注和扩散研究。 在目标1中，我们将把新的DPG方法应用到临床方案中，用于功能、灌注、 以及在3台特斯拉扫描仪上的扩散研究，并表征了信号损失、时间稳定性、 与传统方法相比，具有更高的运动灵敏度和伪影水平。此外，我们还将 将DPG方法整合到新的EPI采集机制中，该机制可以采集多幅图像 同时切片。在目标2中，我们很好地将这些技术应用于高级研究扩散。 和7台特斯拉扫描仪的功能协议，并测试这些方法恢复信号数据的能力 使用目前的图像采集方法已经丢失了这一点。 我们提案的成功将取决于能否描述一项改进的特征 在功能、扩散和灌注成像应用中的时间稳定性。成功者 该项目的完成将直接改善3T和7T磁场强度下的成像研究，通过 提高额叶下部皮质和颞叶成像方法的灵敏度。

The diagnosis and treatment of neuropsychiatric disorders critically depends on characterizing neurological function and the ow of blood in the brain. Functional MRI using the EPI sequence is the current imaging standard for investigating brain function. At ultrahigh eld strength, 7 Tesla, the study of brain function and perfusion is limited by imaging artifacts that are inherent in the EPI data acquisition process. One dominant artifact is EPI ghosting which manifests as copies of the measured signal displaced from the original source location. In certain cases, these displaced copies can appear as ripple artifacts that may change over course of an imaging session, introducing temporal instability into the data. These artifacts appear more prominently at higher magnetic eld strength, particularly when imaging structures deep within the brain. We recently presented a new method, Dual-Polarity GRAPPA (DPG), that ef ciently models and corrects the data sampling inconsistencies that cause ghost and ripple artifacts. This proposal seeks to apply this new method to clinical applications where these artifacts appear, including functional, perfusion, and diffusion studies. In Aim 1, we will apply the new DPG method to clinical protocols for functional, perfusion, and diffusion studies on 3 Tesla scanners, and characterize the signal loss, temporal stability, motion sensitivity, and artifact levels compared to conventional methods. In addition, we will incorporate the DPG method into a new EPI acquisition mechanism that acquires multiple image slices simultaneously. In Aim 2, we well apply these techniques to advanced research diffusion and functional protocols for 7 Tesla scanners, and test the methods' ability to restore signal data that is lost using current image acquisition methods. The success of our proposal will be identi ed by the ability to characterize an improvement in temporal stability in functional, diffusion, and perfusion imaging applications. The successful completion of this project will directly improve imaging studies at both 3T and 7T eld strength, by improving sensitivity in methods that image the inferior frontal cortex and temporal lobes.