Background

Deep brain stimulation (DBS) is an innovative treatment for treatment-refractory depression. DBS is usually targeted at specific anatomical landmarks, with patients responding to DBS in approximately 50% of cases. Attention has recently shifted to white matter tracts to explain DBS response, with initial open-label trials targeting white matter tracts yielding much higher response rates (>70%).

Objective/Hypothesis

Our aim was to associate distance to individual white matter tracts around the stimulation target in the ventral anterior limb of the internal capsule to treatment response.

Methods

We performed diffusion magnetic resonance tractography of the superolateral branch of the medial forebrain bundle and the anterior thalamic radiation in fourteen patients that participated in our randomized clinical trial. We combined the tract reconstructions with the postoperative images to identify the DBS leads and estimated the distance between tracts and leads, which we subsequently associated with treatment response.

Results

Stimulation closer to both tracts was significantly correlated to a larger symptom decrease (r = 0.61, p = 0.02), suggesting that stimulation more proximal to the tracts was beneficial. Biophysical modelling indicated that 37.5% of tracts were even outside the volume of activated tissue. There was no difference in lead placement with respect to anatomical landmarks, which could mean that differences in treatment response were driven by individual differences in white matter anatomy.

Conclusions

Our results suggest that deep brain stimulation of the ventral anterior limb of the internal capsule could benefit from targeting white matter bundles. We recommend acquiring diffusion magnetic resonance data for each individual patient.

中文翻译：

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距白质轨迹的距离与治疗难治性抑郁症对内囊深部脑刺激的治疗反应有关。

背景

深部脑刺激（DBS）是一种用于治疗难治性抑郁症的创新疗法。DBS通常针对特定的解剖标志，大约50％的患者对DBS有反应。最近，注意力已转移到白质领域来解释DBS的反应，针对白质领域的初始开放标签试验产生了更高的缓解率（> 70％）。

目标/假设

我们的目标是将内囊腹侧前肢刺激目标周围的各个白质束的距离与治疗反应相关联。

方法

我们对参加我们随机临床试验的14例患者的前脑内侧束外侧分支和丘脑前部放射进行了磁共振扩散成像。我们将束重建与术后图像结合在一起，以识别DBS导联，并估算出束与导联之间的距离，随后将其与治疗反应相关联。

结果

靠近两个呼吸道的刺激与较大的症状减轻显着相关（r = 0.61，p = 0.02），表明在靠近呼吸道的刺激是有益的。生物物理模型表明，37.5％的管道甚至在活化组织的体积之外。导线在解剖标志方面的放置没有差异，这可能意味着治疗反应的差异是由白质解剖的个体差异所驱动的。

结论

我们的研究结果表明，针对白质束的定位可以对内囊腹侧前肢的深部脑刺激产生益处。我们建议为每个患者获取扩散磁共振数据。