Background:

Diffusion-weighted ¹H magnetic resonance spectroscopy (DW-MRS) allows to quantify creatine-phosphocreatine brain diffusivity (ADC(tCr)), whose reduction in multiple sclerosis (MS) has been proposed as a proxy of energy dysfunction.

Objective:

To investigate whether thalamic ADC(tCr) changes are associated with thalamo-cortical tract damage in MS.

Methods:

Twenty patients with MS and 13 healthy controls (HC) were enrolled in a DW-MRS and DW imaging (DWI) study. From DW-MRS, ADC(tCr) and total N-acetyl-aspartate diffusivity (ADC(tNAA)) were extracted in the thalami. Three thalamo-cortical tracts and one non-thalamic control tract were reconstructed from DWI. Fractional anisotropy (FA), mean (MD), axial (AD), and radial diffusivity (RD), reflecting microstructural integrity, were extracted for each tract. Associations between thalamic ADC(tCr) and tract metrics were assessed using linear regression models adjusting for age, sex, thalamic volume, thalamic ADC(tNAA), and tract-specific lesion load.

Results:

Lower thalamic ADC(tCr) was associated with higher MD and RD of thalamo-cortical projections in MS (MD: p = 0.029; RD: p = 0.017), but not in HC (MD: p = 0.625, interaction term between thalamic ADC(tCr) and group = 0.019; RD: p = 0.320, interaction term = 0.05). Thalamic ADC(tCr) was not associated with microstructural changes of the control tract.

Conclusion:

Reduced thalamic ADC(tCr) correlates with thalamo-cortical tract damage in MS, showing that pathologic changes in thalamic energy metabolism are associated with structural degeneration of connected fibers.

中文翻译：

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丘脑能量功能障碍与多发性硬化症中的丘脑皮质束损伤有关：扩散光谱研究

背景：

扩散加权¹ H 磁共振波谱 (DW-MRS) 允许量化肌酸 - 磷酸肌酸脑扩散率 (ADC(tCr))，其减少多发性硬化症 (MS) 已被提议作为能量功能障碍的代理。

客观的：

研究丘脑 ADC(tCr) 变化是否与 MS 中的丘脑-皮质束损伤有关。

方法：

20 名 MS 患者和 13 名健康对照 (HC) 参加了 DW-MRS 和 DW 成像 (DWI) 研究。从 DW-MRS 中，提取了丘脑中的 ADC(tCr) 和总 N-乙酰-天冬氨酸扩散系数 (ADC(tNAA))。从 DWI 重建了三个丘脑皮质束和一个非丘脑控制束。为每个道提取反映微观结构完整性的各向异性分数 (FA)、平均 (MD)、轴向 (AD) 和径向扩散率 (RD)。使用线性回归模型对年龄、性别、丘脑体积、丘脑 ADC(tNAA) 和道特异性病变负荷进行调整，评估丘脑 ADC(tCr) 和道指标之间的关联。

结果：

较低的丘脑 ADC(tCr) 与 MS 中丘脑皮质投射的较高 MD 和 RD 相关（MD：p  = 0.029；RD：p  = 0.017），但与 HC 无关（MD：p  = 0.625，丘脑 ADC 之间的相互作用项(tCr) 和组 = 0.019；RD：p  = 0.320，交互项 = 0.05)。丘脑 ADC(tCr) 与控制束的微观结构变化无关。

结论：

丘脑 ADC(tCr) 降低与 MS 中丘脑-皮质束损伤相关，表明丘脑能量代谢的病理变化与连接纤维的结构退化有关。