Primary dysmenorrhea (PDM) is a cyclic menstrual pain in the absence of pelvic anomalies, and women with PDM have an increased sensitivity to pain than the internal and external areas associated with menstrual pain. However, the brain abnormality in the ascending pain pathways in dysmenorrhea remains largely unclear. As the thalamus plays a significant role in transmission of nociceptive input, we examined whether white matter microstructure of the thalamus-related fiber tracts obtained by DTI in women with PDM (n = 47) differs from healthy controls. A novel tractography atlas-based analysis method that detects tract integrity and altered microstructural properties along selected fibers was employed. The fiber bundles of interest contained the thalamus- primary somatosensory cortex (SI), thalamus- dorsal anterior cingulate cortex (dACC)/supplementary motor area (SMA), thalamus-insula, and thalamus-ACC. As compared with controls, abnormal white matter microstructures were found along the thalamus-related white matter fiber tracts. Additionally, the intensity of menstrual pain was significantly associated with diffusion measures of thalamus-SI fiber connections. Our study suggested that the thalamus-related pain processing pathways had altered white matter integrity that persisted beyond the time of menstruation, and the white matter microstructure of the thalamus-SI pathways was closely related to menstrual pain in the intensity by women with PDM.

原发性痛经 (PDM) 是一种没有骨盆异常的周期性月经痛，与月经痛相关的内部和外部区域相比，患有 PDM 的女性对疼痛的敏感性更高。然而，痛经中上行疼痛通路的大脑异常仍不清楚。由于丘脑在伤害性输入的传递中起重要作用，我们检查了 PDM 女性的 DTI 获得的丘脑相关纤维束的白质微结构（n = 47) 不同于健康对照。采用了一种新的基于纤维束成像图谱的分析方法，该方法可以检测沿着选定纤维的纤维束完整性和改变的微观结构特性。感兴趣的纤维束包含丘脑-初级躯体感觉皮层 (SI)、丘脑-背侧前扣带皮层 (dACC)/辅助运动区 (SMA)、丘脑-岛叶和丘脑-ACC。与对照组相比，沿着丘脑相关的白质纤维束发现了异常的白质微结构。此外，月经疼痛的强度与丘脑-SI 纤维连接的扩散测量显着相关。我们的研究表明，丘脑相关的疼痛处理途径改变了白质完整性，这种完整性在月经期后持续存在，