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

描述(由申请人提供)：项目摘要：我们建议开发软件来准确模拟从自旋激发到图像重建的MRI过程，严格执行MRI的物理定律，并准确地三维表示人体解剖、场分布以及组织的自旋磁化和松弛特性。输出将是逼真的图像，准确地表示所选样本、序列和场的信号、对比度和噪声分布、静态和与射频场相关的伪像(以及其他许多东西)。这将有助于在MRI系统上实现新的硬件、脉冲或序列之前的评估、修订和优化的中间、低成本阶段。与该软件配合使用时，我们将提供从1.0到9.4特斯拉的几种场强下的真实静态、梯度和射频磁场分布库、人体解剖学、基本脉冲序列和重建方法。用户还将能够输入专门设计的对象解剖结构、不同的组织自旋磁化/松弛属性、在任何场强下的新场分布、奇异脉冲序列和/或新的重建方法。该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)，以便与安全法规进行比较。所有这些都将是免费的和开源的，这样研究人员就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、解剖和生理信息节省了生命和护理成本。人们一直致力于通过使用更高的静电场强度来改进磁共振成像，从而使用更高的射频场频率，但人体应用磁场的扭曲对磁共振成像的进步构成了严重的障碍。通过我们将提供的工具，可以使用计算机在任何场强下对脉冲、序列和硬件进行关键研究、开发和安全评估，以减少在实际MRI系统上实施未经测试的原型所需的磁铁时间和成本。它也将成为MR教育和培训的极好工具。这将大大降低成本，提高磁共振成像的进展速度和可及性，并允许宝贵的磁共振成像系统时间更多地用于重要的医学和科学研究，而不是更少地用于技术发展的评估。

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.