Stretchable Coils for Low-Field, Portable MRI

项目摘要/摘要 便携式磁共振成像(MRI)扫描仪的广泛使用可以 运送到床边可能会对低收入人群的危重护理和普通临床护理产生巨大影响 资源设置。为了实现真正便携的护理点操作，低磁场强度(&lt；0.1T)是 被认为是尺寸要求和安全考虑的先决条件。然而，主要的限制是 低场MRI是与之相关的低信噪比。这些系统的低信噪比导致 与常规MRI相比，图像质量明显较差。而高信噪比并不总是必需的 检测病理时，可能会有很高的漏诊和误诊风险。这是一个重要的问题， 目前，低场磁共振的使用成本很高，最终可能会限制对 便携无障碍核磁共振技术。 提高MR测量灵敏度的一种非侵入性方法是最大化接收器 线圈灵敏度。我们的建议试图通过可伸缩的接收器盖来实现这一点，用于脑成像。这个 可伸缩线圈将适应每个对象，为线圈提供最高的填充系数，并试图实现 身体噪音占优势。我们将不使用损耗可伸缩导线，而是使用灵活的、战略性地覆盖的导线 在可伸缩的盖子上放置Litz导线，以构建单通道接收器线圈。线圈的电感将 由于可改变的直径和形状，每个对象都不同。因此，我们将实现一个 外部调谐和匹配箱，用于“自动调谐”线圈。自动调谐系统将使用紧凑型 上位机控制的矢量网络分析仪(VNA)可监测S线圈的参数并适当输出 电压到压控电容器(变容二极管)的电压，用于可调调谐/匹配。我们的最终目标是 为每个单独的受试者创建最佳的脑成像线圈(通过调整形状和 调谐/匹配)，最终目标是提高便携式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.