Does new magnetic resonance imaging technology provide better geometrical accuracy during stereotactic imaging?
Does new magnetic resonance imaging technology provide better geometrical accuracy during stereotactic imaging?
复制标题
新的磁共振成像技术能否在立体定向成像过程中提供更好的几何精度？
作者：
J. Novotný;J. Vymazal;J. Novotný;D. Tlachacova;M. Schmitt;P. Chuda;D. Urgošík;R. Liščák
对象
作者试图比较使用西门子1T Expert和1.5T SYMPHONY磁共振(MR)设备进行立体定向靶点成像的准确性。
方法
一个充满水的圆柱形有机玻璃体模，带有轴向和冠状插入件，包含玻璃棒网格，固定在Leksell立体定向框架内，在西门子1T Expert和西门子1.5T交响乐设备上进行磁共振成像。每个单位都使用相同的序列。这些图像被传输到GammaPlan治疗计划系统。对于每项研究，评估了基于MR图像的立体定向坐标与通过构建模体插件所给出的估计的真实几何位置之间的偏差。作为所使用的MR单元、MR序列、图像方向和所调查体积中测量点的空间位置的函数，进一步研究偏差。
结论
当使用SYMPHONY 1.5T单元时，观察到比使用Expert 1T单元时更大的失真。Expert 1T的轴位图像和冠状位图像的典型平均失真分别不超过0.6 mm和0.9 mm。SYMPHONY 1.5T的轴位图像和冠状位图像的典型平均失真分别不超过1 mm和1.3 mm。图像序列对两个单元的失真都有影响。在丘脑底核成像中进行的冠状T2加权自旋回波成像在Expert 1T和SYMPHONY 1.5T中产生的最大失真分别为2.6 mm和3 mm。在两个单位中，冠状切片都比轴位切片有更大的扭曲，这种影响在SYMPHONY 1.5T中更为明显。在所研究的体模体积中，位于非中心位置的切片位置与更大的扭曲有关。
OBJECT
The authors sought to compare the accuracy of stereotactic target imaging using the Siemens 1T EXPERT and 1.5T SYMPHONY magnetic resonance (MR) units.
METHODS
A water-filled cylindrical Perspex phantom with axial and coronal inserts containing grids of glass rods was fixed in the Leksell stereotactic frame and subjected to MR imaging in Siemens 1T EXPERT and Siemens 1.5T SYMPHONY units. Identical sequences were used for each unit. The images were transferred to the GammaPlan treatment planning system. Deviations between stereotactic coordinates based on MR images and estimated real geometrical positions given by the construction of the phantom insert were evaluated for each study. The deviations were further investigated as a function of the MR unit used, MR sequence, the image orientation, and the spatial position of measured points in the investigated volume.
CONCLUSIONS
Larger distortions were observed when using the SYMPHONY 1.5T unit than those with the EXPERT 1T unit. Typical average distortion in EXPERT 1T was not more than 0.6 mm and 0.9 mm for axial and coronal images, respectively. Typical mean distortion for SYMPHONY 1.5T was not more than 1 mm and 1.3 mm for axial and coronal images, respectively. The image sequence affected the distortions in both units. Coronal T2-weighted spin-echo images performed in subthalamic imaging produced the largest distortions of 2.6 mm and 3 mm in the EXPERT 1T and SYMPHONY 1.5T, respectively. Larger distortions were observed in coronal slices than in axial slices in both units, and this effect was more pronounced in SYMPHONY 1.5T. Noncentrally located slice positions in the investigated volume of the phantom were associated with larger distortions.