Multi-coil Shimming of the Human Brain at 7 Tesla

7 特斯拉的人脑多线圈匀场

• 批准号: 8637074
• 负责人: ROBIN A DE GRAAF
• 金额: $ 35.18万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8637074
• 关键词: Air; Anatomy; Automation; Brain; Brain Diseases; Brain Injuries; Characteristics; Clinical; Communication; Complex; Computer software; Data; Data Quality; Diagnosis; Diffusion; Echo-Planar Imaging; Electromagnetics; Ensure; Functional Magnetic Resonance Imaging; Generations; Geometry; Gold; Head; Human; Image; Lead; Liquid substance; Magnetic Resonance; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Magnetism; Maps; Measurement; Metabolism; Methods; Modality; Modeling; Morphologic artifacts; Mus; Operative Surgical Procedures; Performance; Predisposition; Problem Solving; Procedures; Protocols documentation; RF coil; Resolution; Shapes; Signal Transduction; Slice; Spatial Distribution; Spectrum Analysis; Stream; Structure; System; Techniques; Tissues; Weight; base; clinical application; flexibility; frontal lobe; human subject; improved; in vivo; innovation; magnetic field; novel; olfactory bulb; operation; quality assurance

DESCRIPTION (provided by applicant): Many magnetic resonance (MR) modalities, like functional MR imaging (MRI), diffusion MRI and MR spectroscopy (MRS) have great potential for the study and diagnosis of brain disease and injury, and guiding surgical therapy. All of these methods benefit greatly from the increased sensitivity, resolution and contrast from high field strength magnets (3T and above). However, the advantages of higher magnetic fields have not been fully realized due to the increasingly confounding effects of magnetic field inhomogeneity caused by magnetic susceptibility differences between air and tissue. Magnetic field inhomogeneity leads to signal loss and spatial distortion in MRI and loss in spectral resolution and sensitivity in MRS. The loss of reliability due to these artifacts is a major reason why these techniques have not seen widespread use in high-field clinical applications. Current methods of magnetic field homogenization based on spherical harmonic shim coils perform well on small volumes but are inadequate to compensate the complex magnetic field distribution across the entire human brain. Here a novel technique based on matrices of DC coils is presented that can achieve superior shimming performance in the human brain in vivo. Preliminary results demonstrate the feasibility of multi-coil (MC) matrix shimming on human brain at 7.0 T. Characterization of the static and temporal characteristics of MC matrices will be established, as well as the integration with RF coils. This application proposes to develop MC matrix shimming to the point where excellent magnetic field homogeneity across the entire human brain at 7 T can be obtained in a robust and automated fashion for use with any existing clinical MR protocol. Specifically, the application is composed of three aims that are focused on optimization of the MC matrix for human brain applications at 7 T (Aim 1), the automation of MC matrix field generation (Aim 2) and demonstration of improved magnetic field homogeneity in a number of MRI, MRS and MRSI applications (Aim 3).

描述（由申请人提供）：许多磁共振（MR）模式，如功能性磁共振成像（MRI）、扩散磁共振成像和磁共振波谱（MRS）在研究和诊断脑部疾病和损伤以及指导手术治疗方面具有巨大潜力。所有这些 高场强磁铁（3T 及以上）提高的灵敏度、分辨率和对比度使这些方法受益匪浅。然而，由于空气和组织之间的磁化率差异引起的磁场不均匀性的影响越来越大，较高磁场的优势尚未完全实现。磁场不均匀性会导致 MRI 中的信号丢失和空间失真以及 MRS 中的光谱分辨率和灵敏度损失。由于这些伪影而导致的可靠性损失是这些技术尚未在高场临床应用中广泛使用的主要原因。目前基于球谐匀场线圈的磁场均匀化方法在小体积上表现良好，但不足以补偿整个人脑的复杂磁场分布。这里提出了一种基于直流线圈矩阵的新技术，可以在人脑体内实现卓越的匀场性能。初步结果证明了在 7.0 T 下对人脑进行多线圈 (MC) 矩阵匀场的可行性。将建立 MC 矩阵的静态和时间特性的表征，以及与射频线圈的集成。该应用建议开发 MC 矩阵匀场，以便能够以稳健且自动化的方式在 7 T 下获得整个人脑的出色磁场均匀性，以便与任何现有的临床 MR 协议一起使用。具体来说，该应用程序由三个目标组成，重点是优化 7 T 下人脑应用的 MC 矩阵（目标 1）、MC 矩阵场生成的自动化（目标 2）以及在许多 MRI、MRS 和 MRSI 应用中演示改进的磁场均匀性（目标 3）。