Gradient-Free Quantitative MRI using a Combination of B1-Selective Excitation and Fingerprinting

结合使用 B1 选择性激励和指纹识别的无梯度定量 MRI

• 批准号: 10630200
• 负责人: William A Grissom
• 金额: $ 66.28万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10630200
• 关键词: 3-Dimensional; Acceleration; Algorithms; Amplifiers; Brain; Brain imaging; Brain scan; Clinical; Complex; Data; Diameter; Dictionary; Disease; Fingerprint; Generations; Head; Heating; Human; Image; Lesion; Loudness; MRI Scans; Machine Learning; Magnetic Resonance Imaging; Maintenance; Maps; Medical Imaging; Methods; Output; Patients; Performance; Peripheral Nerve Stimulation; Phase; Physiologic pulse; Process; Property; RF coil; Reader; Renaissance; Resolution; Rotation; Safety; Scanning; Signal Transduction; Speed; System; Technology; Thinking; Tissues; Training; Translating; Variant; contrast imaging; cost; cost effective; design; experience; experimental study; flexibility; human subject; imaging modality; improved; in vivo; magnetic field; novel; operation; portability; quantitative imaging; radio frequency; radiologist; reconstruction; skills; transmission process; wireless; wireless transmission

Project Summary Magnetic Resonance Imaging (MRI) is one of the most important medical imaging modalities because of its ability to detect and characterize lesions throughout the body. However, access to MRI is severely limited by its expensive hardware, complex siting requirements and typically-qualitative images, which require highly skilled radiologists to interpret. This project proposes a fundamentally new way to encode MRI that could enable sub- stantially cheaper and more flexible quantitative MRI scanners. Today the overwhelming majority of MRI scans are encoded using two primary methods: B0 gradients and parallel imaging using an array of receiver coils. B0 gradients take up a significant fraction of the bore diam- eter; are loud and induce peripheral nerve stimulation, compromising patient comfort; they have relatively long switching times due to the high inductance of the coils; they require bulky cooling systems and customized am- plifiers; they are expensive, representing 25-30% of the cost of a clinical scanner; and they must be carefully designed and customized to a scanner's B0 magnet. B0 gradient encoding also suffers from spatial errors due to concomitant terms, which increase with decreasing B0 field strength and will limit the performance of emerging portable and low-cost MRI systems. Parallel imaging enables scan acceleration by differentiating signals across large spatial distances, but cannot encode complete images on its own. While some have proposed a third class of encoding methods using radiofrequency transmit (B1+) gradients, none of the methods described to date have been translated into clinical use because of practical limits on their performance, stringent hardware requirements and lack of flexibility in image contrast. This project will develop and validate a fourth, fundamentally new way to encode MRI based on parallel transmission using B1+-selective pulses produced by wireless RF coil units with on-coil amplifiers that perform RF transmission and reception, combined with an acquisition and reconstruction process inspired by MR Finger- printing (MRF). This new method, Selective Encoding through Nutation and Fingerprinting (SENF), completely eliminates the need for B0 gradients and is compatible with a wide range of magnet designs and flexible ac- quisition strategies. Unlike previous B1+ imaging methods, SENF places no strict spatial variation requirements on the RF gradient fields, which enables flexible system design, and the same coils can be used for spatial en- coding and signal reception. Furthermore, instead of suffering from errors due to complex spin dynamics during RF encoding, SENF leverages those dynamics to its advantage to differentiate quantitative tissue parameters. Successful completion of this project will enable a new generation of cheaper, more accessible, more modular, and lower-maintenance MRI scanners with quantitative outputs that can be more directly related to disease and tissue states.

项目摘要 磁共振成像（MRI）是最重要的医学成像方式之一 能够检测和表征整个身体的病变。但是，获得MRI的访问受其严重限制 昂贵的硬件，复杂的坐着要求以及通常需要高技能的质量图像 放射学家解释。该项目提出了一种从根本上进行编码MRI的新方法 更便宜，更灵活的定量MRI扫描仪。 如今，绝大多数MRI扫描是使用两种主要方法编码的：B0梯度 并使用接收器线圈阵列进行并行成像。 B0梯度占据了钻头的显着部分 Eter;响亮，引起周围神经刺激，损害患者的舒适感；他们有相对较长的 由于线圈的高电感，切换时间；他们需要笨重的冷却系统和定制的AM- pli;它们很昂贵，占临床扫描仪成本的25-30％；他们必须仔细 设计和定制为扫描仪的B0磁铁。 B0梯度编码还遭受了由于 随之而来的术语，随着B0场强度的降低而增加，并将限制新兴的性能 便携式和低成本MRI系统。并行成像可以通过区分跨越信号的扫描加速度 大空间距离，但不能单独编码完整的图像。虽然有些人提出了三等奖 使用射频传输（B1+）梯度编码方法的编码方法，迄今为止所描述的方法均未 由于其性能，严格的硬件要求而被翻译成临床用途 图像对比度缺乏灵活性。 该项目将开发并验证第四个基于平行的MRI的新方法 使用无线RF线圈单元产生的B1+选择性脉冲的传输，并具有执行的螺旋螺旋体 RF传播和接收，结合了MR Finger的启发的获取和重建过程 印刷（MRF）。这种新方法是通过nutation and Inderprinting（SENF）进行选择性编码的，完全 消除了对B0梯度的需求，并且与广泛的磁铁设计兼容，并具有光泽的AC- 戒烟策略。与以前的B1+成像方法不同，SENF没有严格的空间变化要求 在RF梯度领域，可以实现灵活的系统设计，并且可以将相同的线圈用于空间连接 编码和信号接收。此外，而不是由于复杂的旋转动态而遭受错误 RF编码，SENF利用了这些动力学来区分定量组织参数。 该项目的成功完成将使新一代更便宜，更容易访问，更模块化， 以及具有定量输出的较低维护的MRI扫描仪，可能与疾病和 组织状态。