Kato Sachiko, Maesawa Satoshi, Bagarinao Epifanio, Nakatsubo Daisuke, Tsugawa Takahiko, Mizuno Satomi, Kawabata Kazuya, Tsuboi Takashi, Suzuki Masashi, Shibata Masashi, Takai Sou, Ishizaki Tomotaka, Torii Jun, Mutoh Manabu, Saito Ryuta, Wakabayashi Toshihiko, Katsuno Masahisa, Ozaki Norio, Watanabe Hirohisa, Sobue Gen
1Department of Neurosurgery, Nagoya University Graduate School of Medicine, Nagoya.
2Focused Ultrasound Therapy Center, Nagoya Kyoritsu Hospital, Nakagawa, Nagoya.
J Neurosurg. 2022 Jul 8;138(2):306-317. doi: 10.3171/2022.5.JNS22411. Print 2023 Feb 1.
Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy ameliorates symptoms in patients with essential tremor (ET). How this treatment affects canonical brain networks has not been elucidated. The purpose of this study was to clarify changes of brain networks after MRgFUS thalamotomy in ET patients by analyzing resting-state networks (RSNs).
Fifteen patients with ET were included in this study. Left MRgFUS thalamotomy was performed in all cases, and MR images, including resting-state functional MRI (rsfMRI), were taken before and after surgery. MR images of 15 age- and sex-matched healthy controls (HCs) were also used for analysis. Using rsfMRI data, canonical RSNs were extracted by performing dual regression analysis, and the functional connectivity (FC) within respective networks was compared among pre-MRgFUS patients, post-MRgFUS patients, and HCs. The severity of tremor was evaluated using the Clinical Rating Scale for Tremor (CRST) score pre- and postoperatively, and its correlation with RSNs was examined.
Preoperatively, ET patients showed a significant decrease in FC in the sensorimotor network (SMN), primary visual network (VN), and visuospatial network (VSN) compared with HCs. The decrease in FC in the SMN correlated with the severity of tremor. After MRgFUS thalamotomy, ET patients still exhibited a significant decrease in FC in a small area of the SMN, but they exhibited an increase in the cerebellar network (CN). In comparison between pre- and post-MRgFUS patients, the FC in the SMN and the VSN significantly increased after treatment. Quantitative evaluation of the FCs in these three groups showed that the SMN and VSN increased postoperatively and demonstrated a trend toward those of HCs.
The SMN and CN, which are considered to be associated with the cerebello-thalamo-cortical loop, exhibited increased connectivity after MRgFUS thalamotomy. In addition, the FC of the visual network, which declined in ET patients compared with HCs, tended to normalize postoperatively. This could be related to the hypothesis that visual feedback is involved in tremor severity in ET patients. Overall, the analysis of the RSNs by rsfMRI reflected the pathophysiology with the intervention of MRgFUS thalamotomy in ET patients and demonstrated a possibility of a biomarker for successful treatment.
磁共振引导聚焦超声（MRgFUS）丘脑切开术可改善特发性震颤（ET）患者的症状。但这种治疗如何影响经典脑网络尚未阐明。本研究的目的是通过分析静息态网络（RSN）来阐明ET患者接受MRgFUS丘脑切开术后脑网络的变化。
本研究纳入了15例ET患者。所有病例均进行了左侧MRgFUS丘脑切开术，并在手术前后采集了包括静息态功能磁共振成像（rsfMRI）在内的磁共振图像。15名年龄和性别匹配的健康对照者（HC）的磁共振图像也用于分析。利用rsfMRI数据，通过双回归分析提取经典RSN，并比较MRgFUS术前患者、MRgFUS术后患者和HC之间各网络内的功能连接（FC）。术前和术后使用震颤临床评分量表（CRST）评分评估震颤严重程度，并检查其与RSN的相关性。
术前，与HC相比，ET患者的感觉运动网络（SMN）、初级视觉网络（VN）和视觉空间网络（VSN）中的FC显著降低。SMN中FC的降低与震颤严重程度相关。MRgFUS丘脑切开术后，ET患者在SMN的一小区域内仍表现出FC显著降低，但小脑网络（CN）中的FC增加。比较MRgFUS术前和术后患者，治疗后SMN和VSN中的FC显著增加。对这三组FC的定量评估表明，SMN和VSN术后增加，并呈现出向HC的FC水平发展的趋势。
被认为与小脑-丘脑-皮质环路相关的SMN和CN在MRgFUS丘脑切开术后显示出连接性增加。此外，与HC相比，ET患者中下降的视觉网络FC在术后趋于正常化。这可能与视觉反馈参与ET患者震颤严重程度的假说有关。总体而言，通过rsfMRI对RSN的分析反映了ET患者在MRgFUS丘脑切开术干预下的病理生理学，并证明了成功治疗生物标志物的可能性。
