MR Physics Simulation Package for Pulse, Sequence, and Hardware Design

描述（由申请人提供）：项目摘要：我们建议开发软件，以准确模拟MRI过程，从自旋激发到图像重建，严格执行MRI物理定律，并准确表示人体解剖结构、场分布和组织自旋磁化和弛豫特性。输出将是逼真的图像，准确表示所选样本、序列和场的信号、对比度和噪声分布、静态和RF场相关伪影（以及许多其他内容）。这将有助于在MRI系统上实现新硬件、脉冲或序列之前进行中间、低成本的评估、修订和优化阶段。为了与软件配合使用，我们将提供一个在1.0至9.4特斯拉的几种场强下的真实静态、梯度和RF磁场分布库、人体解剖结构、基本脉冲序列和重建方法。用户还将能够输入专门设计的受试者解剖结构、不同的组织自旋磁化/弛豫特性、任何场强下的新颖场分布、外来脉冲序列和/或新的重建方法。软件还将计算所需脉冲序列的头部平均和最大局部比能量吸收率（SAR），以与安全法规进行比较。所有这些都将免费提供和开源，以便研究人员可以根据他们的特定需求进行修改。相关性：近年来，MRI的进步使其成为医学和研究中的宝贵工具，通过准确的非侵入性诊断，解剖和生理信息挽救了生命和护理成本。通过使用更高的静态场强度以及因此更高的RF场频率，持续的努力致力于改进MRI，但是人体对所施加的场的失真对MRI的进步构成了重大障碍。通过我们提供的工具，将有可能使用计算机在任何场强下对脉冲、序列和硬件进行关键的研究、开发和安全评估，以减少对磁体时间的需求和在实际MRI系统上实施未经测试的原型的成本。它也将成为MR教育和培训的绝佳工具。这将大大降低成本，提高MRI的发展速度和可及性，并允许将宝贵的MRI系统时间更多地用于重要的医学和科学研究，而不是评估技术发展。

DESCRIPTION (provided by applicant): Project Summary: We propose to develop software to accurately simulate the MRI process, from spin excitation through image reconstruction, with rigorous implementation of the physical laws of MRI and accurate 3D representations of human anatomies, field distributions, and tissue spin magnetization and relaxation properties. The output will be realistic images, accurately representing signal, contrast, and noise distributions, static and RF field-related artifacts (among many other things) for the chosen sample, sequence, and fields. This will facilitate an intermediate, low-cost stage of evaluation, revision, and optimization before implementation of novel hardware, pulses, or sequences on an MRI system. For use with the software, we will provide a library of realistic static, gradient, and RF magnetic field distributions at several field strengths from 1.0 to 9.4 tesla, human anatomies, basic pulse sequences, and reconstruction methods. The user will also be able to input specially-designed subject anatomies, different tissue spin magnetization/relaxation properties, novel field distributions at any field strength, exotic pulse sequences, and/or new reconstruction methods. The software will also calculate the head-average and maximum local Specific energy Absorption Rates (SAR) for the desired pulse sequence for comparison to safety regulations. All will be freely available and open-source so researchers can make modifications for their specific needs. Relevance: Advances in MRI have made it an invaluable tool in medicine and research in recent years, saving both lives and cost of care with accurate non-invasive diagnostic, anatomic, and physiologic information. Continual effort is devoted to improving MRI by using higher static field strengths, and thus higher RF field frequencies, but distortions of the applied fields by the human body present significant obstacles to the advancement of MRI. With the tools we will provide it will be possible to perform critical research, development, and safety evaluation of pulses, sequences, and hardware at any field strength using computers to reduce the need for magnet time and the cost of implementing untested prototypes on actual MRI systems. It will also make an excellent tool for MR education and training. This should greatly reduce the cost and increase the speed and accessibility of advancement of MRI and allow for valuable MRI system time to be dedicated more to important medical and scientific studies and less to evaluation of technical developments.