用于小动物脑磁共振成像及功能磁共振成像的正交微波传输带线圈设计

Design of quadrature microstrip transmission line volume coil for small animal MRI/fMRI

目的提出一种适用于小动物整个头部成像的高场射频线圈设计方法,以解决表面线圈在脑深部区域信噪比低的问题。方法采用微波传输带结构,并集成了猫头部固定系统。根据设计结果制作的原型线圈由16个微波传输带单元构成。分别采集了矿物油、水模以及猫脑图像验证线圈性能。结果猫脑感兴趣区域内信噪比及敏感度分布均匀;功能磁共振成像结果清楚显示了连接外侧膝状核及初级视皮层的丘脑皮层视觉网络。结论MTL线圈的动物固定系统能够稳定地固定猫头部,减小运动伪影,提高图像质量;该线圈适用于脑功能磁共振研究,尤其是脑深部区域的fMRI研究。

Objective To develop a new design of microstrip transmission line （MTL） volume coil integrated with head holder for the whole small animal brain MRI, in order to improve the signal-to-noise ratio （SNR） of deep brain region. Methods A prototype coil was developed and constructed using 16 MTL resonant elements. The mineral oil images, saline phantom images and in-vivo cat brain images were acquired for coil test and validation. Results Homogeneity and sensitivity distributed evenly in the entire cat brain. The fMRI clearly displayed the thalamocortical visual network connecting lateral geniculate nucleus and primary visual cortex in the cat brain. Conclusion The MTL volume coil can fix the cat brain stably, decrease the motion artifacts and improve the image quality. The coil is superior for investigating the brain functions, in particular and deep brain regions.