Miki Kohei, Masamune Ken
Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
Institute of Advanced BioMedical Engineering and Science, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, Japan.
Int J Comput Assist Radiol Surg. 2015 Oct;10(10):1687-97. doi: 10.1007/s11548-014-1136-3. Epub 2015 Jan 1.
Low-field open magnetic resonance imaging (MRI) is frequently used for performing image-guided neurosurgical procedures. Intraoperative magnetic resonance (MR) images are useful for tracking brain shifts and verifying residual tumors. However, it is difficult to precisely determine the boundary of the brain tumors and normal brain tissues because the MR image resolution is low, especially when using a low-field open MRI scanner. To overcome this problem, a high-resolution MR image acquisition system was developed and tested.
An MR-compatible manipulator with pneumatic actuators containing an MR signal receiver with a small radiofrequency (RF) coil was developed. The manipulator had five degrees of freedom for position and orientation control of the RF coil. An 8-mm planar RF coil with resistance and inductance of 2.04 [Formula: see text] and 1.00 [Formula: see text] was attached to the MR signal receiver at the distal end of the probe. MR images of phantom test devices were acquired using the MR signal receiver and normal head coil for signal-to-noise ratio (SNR) testing.
The SNR of MR images acquired using the MR signal receiver was 8.0 times greater than that of MR images acquired using the normal head coil. The RF coil was moved by the manipulator, and local MR images of a phantom with a 2-mm grid were acquired using the MR signal receiver. A wide field-of-view MR image was generated from a montage of local MR images.
A small field-of-view RF system with a pneumatic manipulator was integrated in a low-field MRI scanner to allow acquisition of both wide field-of-view and high-resolution MR images. This system is promising for image-guided neurosurgery as it may allow brain tumors to be observed more clearly and removed precisely.
低场开放式磁共振成像（MRI）常用于进行图像引导的神经外科手术。术中磁共振（MR）图像有助于追踪脑移位并验证残留肿瘤。然而，由于MR图像分辨率低，尤其是在使用低场开放式MRI扫描仪时，很难精确确定脑肿瘤与正常脑组织的边界。为克服这一问题，开发并测试了一种高分辨率MR图像采集系统。
开发了一种与MR兼容的带有气动执行器的操纵器，该操纵器包含一个带有小型射频（RF）线圈的MR信号接收器。该操纵器具有五个自由度，用于控制RF线圈的位置和方向。一个电阻为2.04 [公式：见正文]、电感为1.00 [公式：见正文] 的8毫米平面RF线圈连接到探头远端的MR信号接收器上。使用MR信号接收器和普通头部线圈采集体模测试设备的MR图像，以进行信噪比（SNR）测试。
使用MR信号接收器采集的MR图像的SNR比使用普通头部线圈采集的MR图像高8.0倍。通过操纵器移动RF线圈，并使用MR信号接收器采集具有2毫米网格的体模的局部MR图像。从局部MR图像的蒙太奇中生成了一个宽视野MR图像。
一个带有气动操纵器的小视野RF系统被集成到低场MRI扫描仪中，以允许采集宽视野和高分辨率的MR图像。该系统在图像引导神经外科手术方面具有前景，因为它可能使脑肿瘤观察得更清晰并精确切除。
