Department of Surgery Related, Division of Anesthesiology, Kobe University Graduate School of Medicine, Kobe, Japan.
Department of Anesthesiology and Pain Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
Sci Rep. 2019 Sep 9;9(1):12912. doi: 10.1038/s41598-019-49360-1.
Ketamine has been used to treat chronic pain; however, it is still unknown as to what types of chronic pain is ketamine effective against. To identify the effect of administration of subanesthetic-dose ketamine in patients with chronic pain and to clarify the mechanism of the effect, we retrospectively investigated brain functional connectivity using resting-state functional magnetic resonance imaging (rs-fMRI). Patients were divided into responders (Group R: ≥50% improvement on Numerical Rating Scale) and non-responders (Group NR). We compared the differences in terms of brain functional connectivity by seed-to-voxel correlation analysis. Two-sample t-test revealed significant lower connectivity between the medial prefrontal cortex (mPFC) and precuneus in Group R. We also found a significant negative correlation between the improvement rate and functional connectivity strength between the mPFC and precuneus. These findings suggest that subanesthetic-dose ketamine is effective in patients with chronic pain whose brain functional connectivity between the mPFC and precuneus is low. We believe that the current study explored for the first time the correlation between brain functional connectivity and the effect of subanesthetic-dose ketamine for chronic pain and indicated the possibility of use of the predictive marker in pharmacological treatment of chronic pain.
氯胺酮已被用于治疗慢性疼痛，但对于氯胺酮对哪种类型的慢性疼痛有效仍不清楚。为了确定亚麻醉剂量氯胺酮在慢性疼痛患者中的治疗效果，并阐明其作用机制，我们使用静息态功能磁共振成像(rs-fMRI)对脑功能连接进行了回顾性研究。患者分为应答者（Group R：数字评分量表≥50%改善）和无应答者（Group NR）。我们通过种子到体素相关分析比较了两组间脑功能连接的差异。两样本 t 检验显示，在 Group R 中，内侧前额叶皮层（mPFC）和楔前叶之间的连接明显较低。我们还发现 mPFC 和楔前叶之间的改善率与功能连接强度之间存在显著的负相关。这些发现表明，亚麻醉剂量的氯胺酮对 mPFC 和楔前叶之间脑功能连接较低的慢性疼痛患者有效。我们认为，本研究首次探索了脑功能连接与亚麻醉剂量氯胺酮治疗慢性疼痛效果之间的相关性，并表明该方法有可能成为慢性疼痛药物治疗的预测标志物。
