Signal Recovery in Susceptibility Based Functional MRI

描述(由申请人提供)：该项目将开发、分析和评估有效使用功能磁共振成像(MRI)的方法，在靠近空气或骨骼的组织界面的大脑区域使用血氧水平依赖(BOLD)对比度。这个项目的动机是由于组织和空气或骨骼之间的磁化率差异造成的大信号空洞和图像失真。这些伪影在功能磁共振成像中普遍存在于许多下部大脑结构，如眶-额叶、下、内侧颞叶、脑干结构和额极。该项目的进一步动机是fh4RI倾向于使用更高的磁场系统，这提高了大脑许多部分的敏感度，但也加剧了伪影。许多当前用于消除这些失真的技术在检测激活的时间分辨率或灵敏度方面具有很大的成本。作为研究计划的一部分，将开发减少敏感性伪影的方法，但保留标准单次激发功能磁共振成像技术的速度、对运动和生理噪声的健壮性以及对比敏感度。与许多其他方法不同，我们将同时解决面内和通过平面的伪影来源。正在研究的方法包括用于减少信号空洞的三维定制激励脉冲和不对称自旋回波捕获，以及用于减少成像失真的迭代图像重建方法和并行接收器线圈成像。这些方法将在以下方面进行评估：减少易感性诱发伪影的有效性、视觉和运动区激活的可靠性、对副鼻窦附近杏仁核结构激活的敏感性以及时间准确性。这个项目的成功将带来有价值的新的fMRI方法，能够以一种对功能激活敏感和对伪像健壮的方式探测所有主要的大脑结构。这种方法将快速且对大胆对比敏感，允许常见的fMRI技术，如事件相关研究，应用于整个大脑。此外，它们还将极大地帮助研究与各种神经、精神和行为障碍有关的大脑区域，包括疼痛障碍、情感障碍、精神分裂症以及酒精和药物滥用。

DESCRIPTION (provided by applicant): This project will develop, analyze and evaluate methods that enable the efficient use of functional Magnetic Resonance Imaging (MRI) using blood oxygenation level dependent (BOLD) contrast in regions of the brain that are proximal to tissue interfaces with air or bone. This project is motivated by the large signal voids and image distortions caused by magnetic susceptibility differences between tissue and air or bone. These artifacts are ubiquitous in fMRI for many inferior brain structures, for example, orbito-frontal cortex, inferior and medial temporal lobes, brain stem structures and the frontal pole. This project is further motivated by a trend in fh4RI towards using higher magnetic field systems, which improves sensitivity in many parts of the brain, but also exacerbates the artifacts. Many current techniques to remove these distortions have a large cost in terms of temporal resolution or sensitivity for detection of activation. As part of the research plan, methods will be developed that reduce the susceptibility-induced artifact but preserve the speed, robustness to motion and physiological noise, and contrast sensitivity of standard single- shot fMRI techniques. Unlike many other approaches, we will address both in-plane and through-plane sources of artifact. The methods under investigation include three-dimensional tailored excitation pulses and asymmetric spin-echo acquisitions for reduction of signal voids, and iterative image reconstruction methods and parallel receiver coil imaging for reduction of imaging distortions. These methods will be evaluated with respect to effectiveness in reducing susceptibility-induced artifact, reliability of activation in visual and motor areas, sensitivity to activation in the amygdala structure near the paranasal sinus, and temporal accuracy. Success in this project will lead to valuable new fMRI methods capable of probing all major brain structures in a manner that is sensitive to functional activation and robust to artifacts. The methods will be fast and sensitive to BOLD contrast, allowing common fMRI techniques, like event-related studies, to be used over the entire brain. In addition, they will dramatically aid in the study of brain regions implicated in a wide variety of neurological, psychiatric, and behavioral disorders, including pain disorders, affective disorders, schizophrenia, and alcohol and drug abuse.