基于液态金属材料的磁共振超柔射频线圈的研制

  射频接收线圈是决定磁共振成像质量的关键部件。目前，临床磁共振成像系统中的射频接收线圈主要是采用固定形状或半柔性结构，线圈尺寸适用于几乎全部的病人，然而由于人体形态之间的差异较大，在颈部、关节、乳腺、婴儿等成像中，射频接收线圈离成像部位较远，导致图像信噪比较低，进而影响图像质量和临床诊断。超柔射频线圈由于能够很好地贴合成像部位，从而提高图像信噪比，在颈部、关节、乳腺、婴儿等成像应用中展示了巨大的潜力。液态金属作为一种柔性导电材料，具有独特的理化性质，在柔性电子中应用广泛，由于其良好的柔性和导电性，十分适用于超柔射频线圈的设计。

  本论文对液态金属镓铟合金的电导率进行改良，通过液态金属的电润湿原理，将高电导率银微粒加入镓铟合金，在保证液态金属柔性的同时提高电导率。以单通道铜皮线圈为标准，本论文对比多种柔性导电材料制成的单通道线圈性能，结果表明以改良后的液态金属为基材的单通道线圈的信噪比达到了同尺寸铜皮线圈信噪比的95%以上，并且具有较高的柔性。本论文基于改良后的液态金属导体设计开发了超柔8通道颈动脉线圈，与商用8通道颈动脉线圈进行水模成像对比和志愿者成像对比实验。结果表明，在水模成像中，本论文开发的超柔8通道颈动脉线圈在感兴趣区域的信噪比、成像深度、成像均匀性等方面均优于商用8通道颈动脉线圈；在志愿者成像中，超柔8通道颈动脉线圈在颈动脉分叉处血管成像和血管壁成像效果与商用线圈相当，但其可弯折具有更高的舒适度。同时，超柔射频线圈由于良好的贴合性、可变形性，可以应用在多部位成像。在超柔8通道线圈在与商用12通道膝关节线圈的水模成像和志愿者成像对比实验中，基于液态金属材料的超柔射频线圈表现出优异的信噪比性能。

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