School of ITEE, University of Queensland, St Lucia, Queensland, Australia.
Department of Energy, Politecnico di Torino, Torino, Italy.
Magn Reson Med. 2017 Aug;78(2):784-793. doi: 10.1002/mrm.26404. Epub 2016 Sep 8.
Gradient strength and speed are limited by peripheral nerve stimulation (PNS) thresholds. The coil array method allows the gradient field to be moved across the imaging area. This can help reduce PNS and provide faster imaging for image-guided therapy systems such as the magnetic resonance imaging-guided linear accelerator (MRI-linac).
The coil array is designed such that many coils produce magnetic fields, which combine to give the desired gradient profile. The design of the coil array uses two methods: either the singular value decomposition (SVD) of a set of field profiles or the electromagnetic modes of the coil surface.
Two whole-body coils and one experimental coil were designed to investigate the method. The field produced by the experimental coil was compared to simulated results.
The experimental coil region of uniformity (ROU) was moved along the z axis as shown in simulation. The highest observed field deviation was 16.9% at the edge of the ROU with a shift of 35 mm. The whole-body coils showed a median field deviation across all offsets below 5% with an eight-coil basis when using the SVD design method.
Experimental results show the feasibility of a moving imaging region within an MRI with a low number of coils in the array. Magn Reson Med 78:784-793, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
梯度强度和速度受到周围神经刺激 (PNS) 阈值的限制。线圈阵列方法允许梯度场在成像区域内移动。这有助于减少 PNS，并为磁共振引导线性加速器 (MRI-linac) 等图像引导治疗系统提供更快的成像。
线圈阵列的设计使得许多线圈产生磁场，这些磁场组合起来形成所需的梯度轮廓。线圈阵列的设计使用两种方法：一种是一组场轮廓的奇异值分解 (SVD)，另一种是线圈表面的电磁模式。
设计了两个全身线圈和一个实验线圈来研究该方法。实验线圈产生的场与模拟结果进行了比较。
实验线圈的均匀区域 (ROU) 沿着 z 轴移动，如模拟所示。在 ROU 的边缘观察到的最高场偏差为 16.9%，偏移量为 35mm。使用 SVD 设计方法时，全身线圈在所有偏移量下的中位数场偏差均低于 5%，基础为 8 个线圈。
实验结果表明，在 MRI 中使用较少的线圈阵列实现成像区域移动是可行的。磁共振医学杂志 78:784-793, 2017. © 2016 国际磁共振学会。
Zotero 插件