Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA.
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA.
Med Phys. 2020 Jul;47(7):3143-3152. doi: 10.1002/mp.14184. Epub 2020 May 11.
To assess the performance and optimize the MR image quality when using a custom-built flexible radiofrequency (RF) spine coil array fitted between the immobilization device and the patient for spine radiotherapy treatment planning.
A 32 channel flexible custom-designed receive-only coil array has been developed for spine radiotherapy simulation for a 3 T Philips MR scanner. Coil signal-to-noise performance and interactions with standard vendor hardware were assessed. In four volunteers, immobilization molds were created with a dummy version of the array within the mold, and subjects were scanned using the custom array in the mold. Phantoms and normal volunteers were scanned with both the custom spine coil array and the vendor's FDA-approved in-table posterior coil array to compare performance.
The superior-inferior field of view for the custom spine array was ~30 cm encompassing at least 10 vertebrae. A noise correlation matrix showed at least 25 dB isolation between all coil elements. Signal-to-noise ratio (SNR) calculated on a phantom scan at the depth of the spinal cord was a factor of 3 higher with the form-fit spine array as compared to the vendor's posterior coil array. The body coil B transmit map was equivalent with and without the spine array in place demonstrating that the elements are decoupled from the body coil. Volunteer imaging showed improved SNR as compared to the vendor's posterior coil array. The custom array permitted a high degree of acceleration making possible the acquisition of isotropic high-resolution 1.1 × 1.1 × 1.1 mm three-dimensional data set over a 30-cm section of the spine in less than 5 min.
The custom-designed form-fitting flexible spine coil array provided enhanced SNR and increased acceleration compared to the vendor's posterior array. Future studies will assess MR-based spinal cord imaging with the custom coil in comparison to CT myelogram.
评估在脊柱放射治疗计划中使用定制的灵活射频（RF）脊柱线圈阵列在固定装置和患者之间的性能，并优化磁共振（MR）图像质量。
为飞利浦 3T 磁共振扫描仪的脊柱放射治疗模拟开发了一种 32 通道的灵活定制接收线圈阵列。评估了线圈的信噪比性能以及与标准供应商硬件的相互作用。在 4 名志愿者中，在模具内创建了带有阵列的模型，然后使用模具内的定制阵列对患者进行扫描。使用定制的脊柱线圈阵列和供应商的 FDA 批准的内置后线圈阵列对模型和正常志愿者进行扫描，以比较性能。
定制脊柱阵列的上下视野约为 30cm，至少包含 10 个椎体。噪声相关矩阵显示，所有线圈元件之间至少有 25dB 的隔离。在脊髓深度的体模扫描中计算的信噪比（SNR），使用贴合式脊柱阵列比供应商的后线圈阵列高 3 倍。在放置或不放置脊柱阵列的情况下，体线圈 B 传输图是等效的，这表明元件与体线圈是解耦的。志愿者成像显示，与供应商的后线圈阵列相比，SNR 得到了改善。定制阵列允许高度加速，从而能够在不到 5 分钟的时间内，在 30cm 长的脊柱段上采集各向同性高分辨率 1.1×1.1×1.1mm 三维数据集。
与供应商的后线圈阵列相比，定制的贴合式灵活脊柱线圈阵列提供了更高的 SNR 和更高的加速。未来的研究将评估定制线圈在磁共振脊髓成像方面与 CT 脊髓造影的比较。
