论文标题
评估合成生成的CT，用于用于经颅专注超声程序
Evaluation of Synthetically Generated CT for use in Transcranial Focused Ultrasound Procedures
论文作者
论文摘要
经颅聚焦超声（TFU）是一种治疗性超声方法，它通过头骨的声音聚焦到无创的小区域，通常在MRI指导下。 CT成像用于估计各个头骨之间变化的声学特性，以使TFUS程序中有效聚焦，从而使患者暴露于潜在的有害辐射。不需要CT的无需CT即可估算颅骨的声学参数的方法。在这里，我们通过使用基于3D贴片的条件生成对抗网络（CGAN）合成了常规获取的T1加权MRI的CT图像，并评估了使用TFU的处理计划的合成CT（SCT）图像的性能。我们使用声学工具箱K-Wave比较了SCT与TFUS计划的SCT（RCT）图像的性能。进行了3个TFU场景的模拟：1）无像差校正，2）用Kranion计算出的相位校正，以及3）根据时间逆转计算得出的相移。从Kranion，RCT和SCT之间的颅骨密度比，头骨厚度和活动元素的数量分别为0.94、0.92和0.98。在20个目标中，RCT和SCT之间的模拟峰值压力差异最大，没有相位校正（12.4 $ \ pm $ 8.1％），而Kranion阶段（7.3 $ \ pm $ 6.0％）最小。对于所有模拟情况，RCT和SCT之间的峰焦点位置之间的距离小于1.3 mm。真实和合成产生的头骨具有可比的图像相似性，颅骨测量和声学模拟指标。我们的工作证明了用MR合成的CT代替真正的CT进行TFUS计划的可行性。源代码和带有训练模型的Docker图像可在https://github.com/han-liu/synct_tcmrgfus上获得
Transcranial focused ultrasound (tFUS) is a therapeutic ultrasound method that focuses sound through the skull to a small region noninvasively and often under MRI guidance. CT imaging is used to estimate the acoustic properties that vary between individual skulls to enable effective focusing during tFUS procedures, exposing patients to potentially harmful radiation. A method to estimate acoustic parameters in the skull without the need for CT would be desirable. Here, we synthesized CT images from routinely acquired T1-weighted MRI by using a 3D patch-based conditional generative adversarial network (cGAN) and evaluated the performance of synthesized CT (sCT) images for treatment planning with tFUS. We compared the performance of sCT to real CT (rCT) images for tFUS planning using Kranion and simulations using the acoustic toolbox, k-Wave. Simulations were performed for 3 tFUS scenarios: 1) no aberration correction, 2) correction with phases calculated from Kranion, and 3) phase shifts calculated from time-reversal. From Kranion, skull density ratio, skull thickness, and number of active elements between rCT and sCT had Pearson's Correlation Coefficients of 0.94, 0.92, and 0.98, respectively. Among 20 targets, differences in simulated peak pressure between rCT and sCT were largest without phase correction (12.4$\pm$8.1%) and smallest with Kranion phases (7.3$\pm$6.0%). The distance between peak focal locations between rCT and sCT was less than 1.3 mm for all simulation cases. Real and synthetically generated skulls had comparable image similarity, skull measurements, and acoustic simulation metrics. Our work demonstrates the feasibility of replacing real CTs with the MR-synthesized CT for tFUS planning. Source code and a docker image with the trained model are available at https://github.com/han-liu/SynCT_TcMRgFUS
