Stretchable Coils for Low-Field, Portable MRI

项目总结/摘要 便携式磁共振成像（MRI）扫描仪的广泛可用性， 运送到床边可能会对重症监护和一般临床护理产生巨大影响， 资源设置。为了实现真正的便携式护理点操作， 这是尺寸要求和安全考虑的先决条件。然而，主要的局限性 低场MRI是相关的低信噪比（SNR）。这些系统的低SNR导致 与常规MRI相比，图像质量明显较差。虽然高SNR并不总是必要的， 检测病理，可能会有很高的风险漏诊和误诊。这是一个重要的问题， 目前支付低场MRI的使用，并可能最终限制大规模采用和扩大 便携式MRI技术。 用于提高MR测量的灵敏度的一种非侵入性方法是最大化接收器 线圈灵敏度我们的建议试图实现这一点与可伸缩的接收器帽脑成像。的 可拉伸的线圈将适合于每个受试者以提供线圈的最高填充因子 体噪优势而不是使用一个有损拉伸导体，我们将使用灵活的，战略性的悬垂 可拉伸帽上的绞合线以构造单通道接收器线圈。线圈的电感将 由于直径和形状可变，因此随每个受试者而变化。因此，我们将实施一项 外部调谐和匹配盒的“自动调谐”线圈。自动调谐系统将利用一个紧凑的 PC控制的矢量网络分析仪（VNA），用于监测线圈的S参数并输出适当的 电压到压控电容器（变容二极管），用于可调调谐/匹配。我们的最终目标是 为每个个体对象创建最佳的脑成像线圈（通过调整形状和 调谐/匹配），最终目的是提高便携式MRI图像质量和临床实用性。

Project Summary/Abstract The widespread availability of portable Magnetic Resonance Imaging (MRI) scanners that can be transported to the bedside could have a tremendous impact for critical care and general clinical care in low- resource settings. To achieve truly portable, point-of-care operation, a low magnetic field strength (<0.1 T) is considered a prerequisite for both size requirements and safety considerations. However, the main limitation of low-field MRI is the associated low signal-to-noise (SNR) ratio. The low SNR of these systems results in significantly inferior image quality compared to conventional MRI. While high SNR is not always necessary to detect pathology, there may be a high risk of missed findings and misdiagnosis. This is a significant issue that currently defrays the use of low-field MRI and could ultimately limit the widescale adoption and scale-up of portable accessible MRI technology. One non-invasive method for improving the sensitivity of the MR measurement, is to maximize the receiver coil sensitivity. Our proposal attempts to achieve this with stretchable receiver caps for brain imaging. The stretchable coils will adapt to each subject to provide the highest filling factor for the coil and attempt to achieve body-noise dominance. Instead of using a lossy stretchable conductor, we will use flexible, strategically draped litz wire on a stretchable cap to construct the single channel receiver coil. The inductance of the coil will change with each subject due to the change-able diameter and shape. Therefore, we will implement an external tuning and matching box for “autotuning” the coil. The autotuning system will make use of a compact PC-controlled vector network analyzer (VNA) to monitor the S-parameters of the coil and output appropriate voltages to voltage-controlled capacitors (varactor diodes) for adjustable tuning/matching. Our end goal is to create the optimal brain imaging coil for each individual subject (through adapting the shape and tuning/matching) with the ultimate goal of improving portable MRI image quality and clinical utility.