Department of Neurosurgery, Albany Medical College, Albany, New York.
Department of Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts.
Neurosurgery. 2019 May 1;84(5):1138-1148. doi: 10.1093/neuros/nyy266.
Ablative lesions are current treatments for epilepsy and brain tumors. Interstitial magnetic resonance (MR) guided focused ultrasound (iMRgFUS) may be an alternate ablation technique which limits thermal tissue charring as compared to laser therapy (LITT) and can produce larger ablation patterns nearer the surface than transcranial MR guided focused ultrasound (tcMRgFUS).
To describe our experience with interstitial focused ultrasound (iFUS) ablations in swine, using MR-guided robotically assisted (MRgRA) delivery.
In an initial 3 animals, we optimized the workflow of the robot in the MR suite and made modifications to the robotic arm to allow range of motion. Then, 6 farm pigs (4 acute, 2 survival) underwent 7 iMRgFUS ablations using MRgRA. We altered dosing to explore differences between thermal dosing in brain as compared to other tissues. Imaging was compared to gross examination.
Our work culminated in adjustments to the MRgRA, iMRgFUS probes, and dosing, culminating in 2 survival surgeries; swine had ablations with no neurological sequelae at 2 wk postprocedure. Immediately following iMRgFUS therapy, diffusion-weighted imaging, and T1 weighted MR were accurate reflections of the ablation volume. T2 and fluid-attenuated inversion-recovery (FLAIR) images were accurate reflections of ablation volume 1-wk postprocedure.
We successfully performed MRgRA iFUS ablation in swine and found intraoperative and postoperative imaging to correlate with histological examination. These data are useful to validate our system and to guide imaging follow-up for thermal ablation lesions in brain tissue from our therapy, tcMRgFUS, and LITT.
消融性病变是目前治疗癫痫和脑肿瘤的方法。间质磁共振（MR）引导聚焦超声（iMRgFUS）可能是一种替代消融技术，与激光治疗（LITT）相比，它可以限制热组织碳化，并能在靠近表面的地方产生比经颅 MR 引导聚焦超声（tcMRgFUS）更大的消融模式。
描述我们在猪身上使用 MR 引导机器人辅助（MRgRA）输送进行间质聚焦超声（iFUS）消融的经验。
在最初的 3 只动物中，我们优化了 MR 套件中机器人的工作流程，并对机器人臂进行了修改，以允许运动范围。然后，6 只农场猪（4 只急性，2 只存活）接受了 7 次 iMRgFUS 消融，采用 MRgRA。我们改变了剂量，以探索大脑与其他组织之间的热剂量差异。将影像学与大体检查进行了比较。
我们的工作最终调整了 MRgRA、iMRgFUS 探头和剂量，最终进行了 2 次存活手术；猪在术后 2 周没有出现神经后遗症。iMRgFUS 治疗后立即进行弥散加权成像和 T1 加权 MR，准确反映了消融体积。T2 和液体衰减反转恢复（FLAIR）图像在术后 1 周准确反映了消融体积。
我们成功地在猪身上进行了 MRgRA iFUS 消融，并发现术中及术后影像学与组织学检查相符。这些数据有助于验证我们的系统，并指导我们的治疗方法（tcMRgFUS 和 LITT）的脑组织热消融病变的影像学随访。
