Abstract：
OBJECTIVE: To investigate iron and myelin changes in deep gray matter (DGM) of relapsing-remitting multiple sclerosis (RRMS) patients and their relationship to atrophy by χ-separation imaging.
METHODS: 33 RRMS patients and 34 healthy controls (HC) were included in this study. The χ-separation map reconstructed from a 3D multi-echo gradient echo scan was used to measure the positive susceptibility (χpos) and negative susceptibility (χneg) of DGM. To take into account the effect of atrophy, susceptibility mass of DGM was calculated by multiplying volume by the mean bulk susceptibility. Differences in MRI metrics between baseline patients, follow-up patients, and HC were compared respectively.
RESULTS: Compared to HC, χpos of basal ganglia were significantly increased in follow-up patients (P < 0.05). The χpos of pallidum was significantly higher in follow-up patients than that in baseline patients (P = 0.006). The χneg of caudate, pallidum and hippocampus in baseline and follow-up patients was significantly higher than that in HC (P < 0.05). When taking into account the effect of atrophy, there was a significant decrease in χpos mass and a significant increase in χneg mass of thalamus, accumbens and amygdala in follow-up patients compared to HC (P < 0.05). The χpos mass of the thalamus was further decreased in follow-up patients compared to baseline patients (P = 0.006).
CONCLUSIONS: χ-separation imaging could generate independent information on iron and myelin changes in RRMS patients, showing atrophy-dependent iron increase in basal ganglia and atrophy-independent iron and myelin decrease in thalamus.
METHODS: 33 RRMS patients and 34 healthy controls (HC) were included in this study. The χ-separation map reconstructed from a 3D multi-echo gradient echo scan was used to measure the positive susceptibility (χpos) and negative susceptibility (χneg) of DGM. To take into account the effect of atrophy, susceptibility mass of DGM was calculated by multiplying volume by the mean bulk susceptibility. Differences in MRI metrics between baseline patients, follow-up patients, and HC were compared respectively.
RESULTS: Compared to HC, χpos of basal ganglia were significantly increased in follow-up patients (P < 0.05). The χpos of pallidum was significantly higher in follow-up patients than that in baseline patients (P = 0.006). The χneg of caudate, pallidum and hippocampus in baseline and follow-up patients was significantly higher than that in HC (P < 0.05). When taking into account the effect of atrophy, there was a significant decrease in χpos mass and a significant increase in χneg mass of thalamus, accumbens and amygdala in follow-up patients compared to HC (P < 0.05). The χpos mass of the thalamus was further decreased in follow-up patients compared to baseline patients (P = 0.006).
CONCLUSIONS: χ-separation imaging could generate independent information on iron and myelin changes in RRMS patients, showing atrophy-dependent iron increase in basal ganglia and atrophy-independent iron and myelin decrease in thalamus.
摘要：
目的：通过χ分离成像研究复发缓解型多发性硬化（RRMS）患者深灰质（DGM）中铁和髓鞘的变化及其与萎缩的关系。
方法：本研究包括33例RRMS患者和34例健康对照（HC）。从3D多回波梯度回波扫描重建的χ分离图用于测量DGM的正磁化率（χpos）和负磁化率（χneg）。考虑到萎缩的影响，DGM的敏感性质量是通过将体积乘以平均体积敏感性来计算的。基线患者之间的MRI指标差异，随访患者，分别与HC进行比较。
结果：与HC相比，随访患者基底节区的χpos值明显升高(P<0.05)。随访患者苍白球的χpos明显高于基线患者（P=0.006）。尾状的χneg，基线和随访患者的苍白球和海马明显高于HC（P<0.05）。当考虑到萎缩的影响时，丘脑的χpos质量显着下降，χneg质量显着增加，随访患者中伏隔和杏仁核与HC比拟(P<0.05)。与基线患者相比，随访患者丘脑的χpos质量进一步降低（P=0.006）。
结论：χ分离成像可以产生有关RRMS患者铁和髓鞘变化的独立信息，显示基底神经节中萎缩依赖性铁增加，丘脑中萎缩依赖性铁和髓鞘减少。
方法：本研究包括33例RRMS患者和34例健康对照（HC）。从3D多回波梯度回波扫描重建的χ分离图用于测量DGM的正磁化率（χpos）和负磁化率（χneg）。考虑到萎缩的影响，DGM的敏感性质量是通过将体积乘以平均体积敏感性来计算的。基线患者之间的MRI指标差异，随访患者，分别与HC进行比较。
结果：与HC相比，随访患者基底节区的χpos值明显升高(P<0.05)。随访患者苍白球的χpos明显高于基线患者（P=0.006）。尾状的χneg，基线和随访患者的苍白球和海马明显高于HC（P<0.05）。当考虑到萎缩的影响时，丘脑的χpos质量显着下降，χneg质量显着增加，随访患者中伏隔和杏仁核与HC比拟(P<0.05)。与基线患者相比，随访患者丘脑的χpos质量进一步降低（P=0.006）。
结论：χ分离成像可以产生有关RRMS患者铁和髓鞘变化的独立信息，显示基底神经节中萎缩依赖性铁增加，丘脑中萎缩依赖性铁和髓鞘减少。
