Open-source software and hardware tools for local B0 field control

用于本地B0现场控制的开源软件和硬件工具

• 批准号: 10251237
• 负责人: Jason P Stockmann
• 金额: $ 21.21万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-20 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10251237
• 关键词: Adoption; Affect; Amplifiers; Area; Brain; Charge; Communities; Computer software; Computers; Coupling; Custom; Data; Diffusion; Diffusion Magnetic Resonance Imaging; Echo-Planar Imaging; Expedite Dissemination; Feedback; Financial compensation; Goals; Hand; Image; Joints; Least-Squares Analysis; Lipids; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Malignant Neoplasms; Maps; Methods; Molecular Profiling; Morphologic artifacts; Noise; Output; Physiologic pulse; Plug-in; Predisposition; Process; Productivity; Protocols documentation; Publishing; Research; Research Personnel; Resource Sharing; Resources; Scanning; Signal Transduction; Site; Slice; Software Tools; Specific qualifier value; Structure; Time; Tissues; Translating; Update; Work; anxious; contrast imaging; cost; design; digital; experimental study; flexibility; graphical user interface; improved; in vivo; instrumentation; interest; magnetic field; open source; physical separation; prevent; programs; prototype; scale up; simulation software; soft tissue; software development; tool; tumor; usability; user-friendly; voltage; web site

Project Summary/Abstract Multi-coil (MC) shim arrays have emerged as a promising and flexible tool for improving MRI image quality. Arrays of small, independently-driven loops placed close to the body provide an efficient way to generate rapidly-switchable magnetic field offsets (ΔB0) that can be shaped to provide useful field profiles inside the body. MC arrays were originally proposed for dynamically-switchable, high spatial order “B0 shimming” in the body to null subject-specific perturbations of the static background B0 field. The improved shimming reduces geometric distortion in echo planar imaging (widely used for functional and diffusion MRI) and line broadening in MR spectroscopy. However, in the past few years, a surge of new uses for MC arrays have been proposed, including supplementary spatial encoding, improved lipid suppression, zoomed imaging, and reduced flip angle (B1+) inhomogeneity. This diverse and growing set of methods – which we classify as local field control – exploit two core features of MC arrays: (1) the ability of non-orthogonal ΔB0 basis sets to generate field profiles that can not be created with linear gradients; and (2) the ability to rapidly update shim currents without causing artifacts. Unfortunately, MC local field control research has been slow to spread beyond a small handful of sites due to limited availability of instrumentation as well as control software. Commercial shim amplifiers with dynamic switching capability are rare, and those that do exist are cost-prohibitive for most applications (>$1,000/channel). At the same time, there is no readily-available software for controlling shim amplifiers and interfacing with the scanner host computer. Moreover, there is a lack of software tools using convex optimization to efficiently solve for shim current amplitudes for tailored local field control. We will break down these barriers to entry by developing an open-source resource called AFFECT (Automated Flexible Field Encoding and Control Toolkit). We will refine and disseminate our previously-validated low-cost ($100- 150/channel), low-voltage shim amplifier that is scalable up to 64-channels. We will also upgrade and package a graphical-user-interface (GUI) used to process B0 field maps and compute optimal shim currents. The GUI will be made modular to allow users to plug in their own custom shim optimization tools. Finally, we will create a seamless interface between the GUI and the scanner host computer to improve workflow. More than 10 research groups have already contacted us asking to use our open-source shim amplifiers. However, further work is required to prepare both the hardware and software for dissemination. The goal of this project is to translate our prototypes into robust, user-extensible tools that are packaged and documented. To expedite dissemination, we will provide up to 10 research groups with 32-channel amplifier setups free of charge. Users will also be free to download schematics and fabricate the circuit boards on their own.

项目总结/摘要 多线圈（MC）匀场阵列已成为一个有前途的和灵活的工具，以提高MRI图像质量。 靠近身体放置的独立驱动的小循环阵列提供了一种有效的方法来生成 可快速切换的磁场偏移（Δ B 0），其形状可在 身体MC阵列最初被提出用于动态可切换的高空间阶“B 0匀场”， 体以使静态背景B 0场的特定于对象的扰动为零。改进的匀场减少了 回波平面成像（广泛用于功能和弥散MRI）中的几何失真和线增宽 核磁共振波谱学。然而，在过去的几年里，MC阵列的新用途激增， 包括补充空间编码、改善脂质抑制、缩放成像和减小翻转角 (B1+）不均匀性。我们将这种多样化的、不断发展的方法归类为局部现场控制- 利用MC阵列的两个核心特性：（1）非正交Δ B 0基组产生场分布的能力 不能用线性梯度创建;以及（2）快速更新匀场电流而不引起 藏物 不幸的是，MC当地的现场控制研究一直缓慢蔓延到少数网站以外， 仪器和控制软件的可用性有限。具有动态特性的商用匀场放大器 交换能力是罕见的，而那些确实存在的交换能力对于大多数应用来说是成本过高的 （> 1，000美元/频道）。同时，没有现成的软件用于控制匀场放大器， 与扫描仪主机连接。此外，缺乏使用凸 优化可有效求解匀场电流幅度，以实现定制的局部磁场控制。我们将打破 通过开发一个名为AFFECT（自动化灵活字段）的开源资源， 编码和控制工具包）。我们将完善和传播我们以前验证的低成本（100美元- 150/通道），低电压匀场放大器，可扩展至64通道。我们还会升级打包 图形用户界面（GUI），用于处理B 0场图并计算最佳匀场电流。的GUI 将模块化，允许用户插入自己的定制垫片优化工具。最后，我们将创建 GUI和扫描仪主机之间的无缝接口，以改善工作流程。 已有10多个研究小组与我们联系，要求使用我们的开源匀场放大器。 然而，还需要进一步的工作来准备硬件和软件以供分发。的目标 这个项目是将我们的原型转换成强大的，用户可扩展的工具，并打包和记录。 为了加快传播速度，我们将免费为多达10个研究小组提供32通道放大器设置， 消费标准.用户还可以免费下载原理图，并自行制作电路板。