Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany; Neuroimaging Core Unit Munich - NICUM, University Hospital, LMU Munich, Munich, Germany.
High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; Brain Stimulation Lab, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, USA.
Neuroimage. 2024 May 1;291:120596. doi: 10.1016/j.neuroimage.2024.120596. Epub 2024 Mar 29.
Left prefrontal intermittent theta-burst stimulation (iTBS) has emerged as a safe and effective transcranial magnetic stimulation (TMS) treatment protocol in depression. Though network effects after iTBS have been widely studied, the deeper mechanistic understanding of target engagement is still at its beginning. Here, we investigate the feasibility of a novel integrated TMS-fMRI setup and accelerated echo planar imaging protocol to directly observe the immediate effects of full iTBS treatment sessions.
OBJECTIVE/HYPOTHESIS: In our effort to explore interleaved iTBS-fMRI feasibility, we hypothesize that TMS will induce acute BOLD signal changes in both the stimulated area and interconnected neural regions.
Concurrent TMS-fMRI with full sessions of neuronavigated iTBS (i.e. 600 pulses) of the left dorsolateral prefrontal cortex (DLPFC) was investigated in 18 healthy participants. In addition, we conducted four TMS-fMRI sessions in a single patient on long-term maintenance iTBS for bipolar depression to test the transfer to clinical cases.
Concurrent TMS-fMRI was feasible for iTBS sequences with 600 pulses. During interleaved iTBS-fMRI, an increase of the BOLD signal was observed in a network including bilateral DLPFC regions. In the clinical case, a reduced BOLD response was found in the left DLPFC and the subgenual anterior cingulate cortex, with high variability across individual sessions.
Full iTBS sessions as applied for the treatment of depressive disorders can be established in the interleaved iTBS-fMRI paradigm. In the future, this experimental approach could be valuable in clinical samples, for demonstrating target engagement by iTBS protocols and investigating their mechanisms of therapeutic action.
左前额叶间歇性 theta 爆发刺激（iTBS）已成为一种安全有效的经颅磁刺激（TMS）治疗方案，用于治疗抑郁症。尽管 iTBS 后的网络效应已得到广泛研究，但对目标参与的更深层次的机制理解仍处于起步阶段。在这里，我们研究了一种新型的集成 TMS-fMRI 设备和加速回波平面成像协议的可行性，以直接观察完整 iTBS 治疗过程的即时效果。
目的/假设：在探索交错 iTBS-fMRI 的可行性的过程中，我们假设 TMS 将在刺激区域和相互连接的神经区域中引起急性 BOLD 信号变化。
对 18 名健康参与者进行了全序列导航 iTBS（即 600 个脉冲）左背外侧前额叶皮质（DLPFC）的同步 TMS-fMRI 研究。此外，我们在一名长期接受 iTBS 治疗的双相抑郁症患者中进行了四次 TMS-fMRI 研究，以测试向临床病例的转化。
600 个脉冲的 iTBS 序列的同步 TMS-fMRI 是可行的。在交错 iTBS-fMRI 期间，观察到一个包括双侧 DLPFC 区域的网络中的 BOLD 信号增加。在临床病例中，左侧 DLPFC 和扣带回前下皮质的 BOLD 反应减少，个体治疗过程中的变异性很大。
用于治疗抑郁症的完整 iTBS 疗程可以在交错 iTBS-fMRI 范式中建立。在未来，这种实验方法在临床样本中可能具有重要价值，可用于证明 iTBS 方案的目标参与，并研究其治疗作用的机制。
