Denier Niklaus, Grieder Matthias, Jann Kay, Breit Sigrid, Mertse Nicolas, Walther Sebastian, Soravia Leila M, Meyer Agnes, Federspiel Andrea, Wiest Roland, Bracht Tobias
Translational Research Center, University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, Bern, Switzerland.
Translational Research Center, University Hospital of Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland.
Neuroimage. 2024 Aug 15;297:120671. doi: 10.1016/j.neuroimage.2024.120671. Epub 2024 Jun 18.
Numerous studies show that electroconvulsive therapy (ECT) induces hippocampal neuroplasticity, but findings are inconsistent regarding its clinical relevance. This study aims to investigate ECT-induced plasticity of anterior and posterior hippocampi using mathematical complexity measures in neuroimaging, namely Higuchi's fractal dimension (HFD) for fMRI time series and the fractal dimension of cortical morphology (FD-CM). Furthermore, we explore the potential of these complexity measures to predict ECT treatment response.
Twenty patients with a current depressive episode (16 with major depressive disorder and 4 with bipolar disorder) underwent MRI-scans before and after an ECT-series. Twenty healthy controls matched for age and sex were also scanned twice for comparison purposes. Resting-state fMRI data were processed, and HFD was computed for anterior and posterior hippocampi. Group-by-time effects for HFD in anterior and posterior hippocampi were calculated and correlations between HFD changes and improvement in depression severity were examined. For FD-CM analyses, we preprocessed structural MRI with CAT12's surface-based methods. We explored group-by-time effects for FD-CM and the predictive value of baseline HFD and FD-CM for treatment outcome.
Patients exhibited a significant increase in bilateral hippocampal HFD from baseline to follow-up scans. Right anterior hippocampal HFD increase was associated with reductions in depression severity. We found no group differences and group-by-time effects in FD-CM. After applying a whole-brain regression analysis, we found that baseline FD-CM in the left temporal pole predicted reduction of overall depression severity after ECT. Baseline hippocampal HFD did not predict treatment outcome.
This study suggests that HFD and FD-CM are promising imaging markers to investigate ECT-induced neuroplasticity associated with treatment response.
大量研究表明，电休克治疗（ECT）可诱导海马神经可塑性，但其临床相关性的研究结果并不一致。本研究旨在利用神经影像学中的数学复杂性测量方法，即功能磁共振成像（fMRI）时间序列的 Higuchi 分形维数（HFD）和皮质形态分形维数（FD-CM），研究 ECT 诱导的前后海马可塑性。此外，我们还探讨了这些复杂性测量方法预测 ECT 治疗反应的潜力。
20 例当前患有抑郁发作的患者（16 例重度抑郁症患者和 4 例双相情感障碍患者）在接受一系列 ECT 治疗前后接受了磁共振成像（MRI）扫描。为作比较，20 名年龄和性别匹配的健康对照者也进行了两次扫描。对静息态 fMRI 数据进行处理，并计算前后海马的 HFD。计算前后海马 HFD 的组间时间效应，并检查 HFD 变化与抑郁严重程度改善之间的相关性。对于 FD-CM 分析，我们使用 CAT12 的基于表面的方法对结构 MRI 进行预处理。我们探讨了 FD-CM 的组间时间效应以及基线 HFD 和 FD-CM 对治疗结果的预测价值。
从基线扫描到随访扫描，患者双侧海马 HFD 显著增加。右侧前海马 HFD 的增加与抑郁严重程度的降低相关。我们在 FD-CM 中未发现组间差异和组间时间效应。应用全脑回归分析后，我们发现左侧颞极的基线 FD-CM 可预测 ECT 后总体抑郁严重程度的降低。基线海马 HFD 不能预测治疗结果。
本研究表明，HFD 和 FD-CM 是研究与治疗反应相关的 ECT 诱导神经可塑性的有前景的影像学标志物。
