Department of Radiology and Radiological Sciences, Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.
Epilepsia. 2024 Mar;65(3):675-686. doi: 10.1111/epi.17889. Epub 2024 Jan 19.
To understand the potential behavioral and cognitive effects of mesial temporal resection for temporal lobe epilepsy (TLE) a method is required to characterize network-wide functional alterations caused by a discrete structural disconnection. The objective of this study was to investigate network-wide alterations in brain dynamics of patients with TLE before and after surgical resection of the seizure focus using average regional controllability (ARC), a measure of the ability of a node to influence network dynamics.
Diffusion-weighted imaging (DWI) data were acquired in 27 patients with drug-resistant unilateral mesial TLE who underwent selective amygdalohippocampectomy. Imaging data were acquired before and after surgery and a presurgical and postsurgical structural connectome was generated from whole-brain tractography. Edge-wise strength, node strength, and node ARC were compared before and after surgery. Direct and indirect edge-wise strength changes were identified using patient-specific simulated resections. Direct edges were defined as primary edges disconnected by the resection zone itself. Indirect edges were secondary measured edge strength changes. Changes in node strength and ARC were then related to both direct and indirect edge changes.
We found nodes with significant postsurgical changes in both node strength and ARC surrounding the resection zone (paired t tests, p < .05, Bonferroni corrected). ARC identified additional postsurgical changes in nodes outside of the resection zone within the ipsilateral occipital lobe, which were associated with indirect edge-wise strength changes of the postsurgical network (Fisher's exact test, p < .001). These indirect edge-wise changes were facilitated through the "hub" nodes including the thalamus, putamen, insula, and precuneus.
Discrete network disconnection from TLE resection results in widespread structural and functional changes not predicted by disconnection alone. These can be well characterized by dynamic controllability measures such as ARC and may be useful for investigating changes in brain function that may contribute to seizure recurrence and behavioral or cognitive changes after surgery.
为了了解内侧颞叶切除术（TLE）对行为和认知的潜在影响，需要一种方法来描述离散结构连接中断引起的全网络功能改变。本研究的目的是使用平均区域可控性（ARC）来研究 TLE 患者在手术切除致痫灶前后大脑动力学的全网络改变，ARC 是衡量节点影响网络动力学能力的指标。
对 27 例药物难治性单侧内侧 TLE 患者进行了研究，这些患者接受了选择性杏仁核海马切除术。在手术前后采集了弥散加权成像（DWI）数据，并从全脑追踪生成了术前和术后结构连接组。比较了手术前后的边缘强度、节点强度和节点 ARC。使用患者特定的模拟切除来识别直接和间接的边缘强度变化。直接边缘定义为被切除区域本身断开的主要边缘。间接边缘是次要的测量边缘强度变化。然后将节点强度和 ARC 的变化与直接和间接的边缘变化相关联。
我们发现，在切除区域周围的节点中，节点强度和 ARC 都有显著的术后变化（配对 t 检验，p<0.05，Bonferroni 校正）。ARC 确定了术后网络中切除区域外的节点的额外术后变化，这些变化与术后网络的间接边缘强度变化相关（Fisher 精确检验，p<0.001）。这些间接的边缘强度变化是通过丘脑、壳核、岛叶和楔前叶等“枢纽”节点来实现的。
TLE 切除引起的离散网络断开导致了广泛的结构和功能变化，这些变化不能仅由断开连接来预测。这些可以通过动态可控性测量来很好地描述，如 ARC，这可能有助于研究可能导致手术后癫痫发作复发和行为或认知变化的脑功能变化。
