多模态MRI在复发缓解型多发性硬化深部灰质的应用

Deep gray matter changes in relapsing-remitting multiple sclerosis detected by multimodal MRI

目的 使用多模态MRI量化复发缓解型多发性硬化(relapsing-remitting multiple sclerosis,RRMS)患者疾病相对早期脑深部灰质改变,并探究其与白质病变及临床残疾的相关性。材料与方法 前瞻性纳入40例RRMS患者和32例健康对照(healthy controls,HC)组,行3D-T1WI、3D-液体衰减反转恢复(fluid attenuated inversion recovery,FLAIR)、定量磁敏感图(quantitative sensitivity mapping,QSM)和扩散张量成像(diffusion tensor imaging,DTI)扫描,获得灰质核团体积、定量磁化率值(quantitative susceptibility value,QSV)、各向异性分数(fractional anisotropy,FA)和平均扩散率(mean diffusivity,MD)值及白质病灶体积(white matter lesion volume,WM-LV)。独立样本t检验比较组间灰质核团体积、QSV、FA和MD值差异,相关分析评估核团各指标与扩展残疾状态量表(Expanded Disability Status Scale,EDSS)评分及WM-LV的相关性。结果 (1)与HC相比,RRMS组各核团体积均减小(P均<0.05),丘脑QSV减低(P<0.05),尾状核及丘脑FA值减低、MD值升高(P均<0.05);(2)相关性分析示各核团体积及尾状核FA值与WM-LV呈负相关(r=-0.315、r=-0.531、r=-0.563、r=-0.635、r=-0.543,P均<0.05),尾状核、壳核及丘脑MD值与WM-LV呈正相关(r=0.620、r=0.671、r=0.558,P均<0.01),余核团FA、MD值及QSV与WM-LV均无显著相关性(P均>0.05);(3)丘脑QSV与EDSS评分呈显著负相关(rs=-0.370,P=0.019)。结论 RRMS疾病相对早期深部灰质明显萎缩,伴有微结构损伤及铁紊乱,且灰质异常部分独立于白质局灶性脱髓鞘;丘脑受累是RRMS的重要特征,其铁浓度可能成为MS疾病严重程度的标志并监测疾病进展。

Objective:To quantify the deep gray matter changes at the relatively early course of relapsing-remitting multiple sclerosis(RRMS)patients by multimodal MRI,and explore its correlation with white matter lesion and clinical disability.Materials and Methods:3D-T1weighted imaging,3D-fluid attenuated inversion recovery,quantitative sensitivity mapping and diffusion tensor imaging scans were performed on 40 patients with RRMS and 32 healthy controls(HC) to obtain gray matter nucleus volume,quantitative susceptibility value(QSV),fractional anisotropy(FA) and mean diffusivity(MD) values and white matter lesion volume(WM-LV).The independent sample t-test was used to compare the differences in the gray matter nucleus volume,QSV,FA and MD values between groups,and correlation analysis was used to assess the relationship between the indicators and the Extended Disability Scale(EDSS) score and WM-LV.Results:Compared with the control group,the volume of each nucleus in the RRMS group was reduced(all P<0.05),and the QSV of the thalamus was reduced(P<0.05);the FA value of the caudate nucleus and thalamus were reduced,and the MD value were increased(P<0.05).Correlation analysis showed the volume of each nucleus and the FA value of the caudate nucleus were negatively correlated with WM-LV(r=-0.315,r=-0.531,r=-0.563,r=-0.635,r=-0.543,all P<0.05),and the MD values of the caudate nucleus,putamen and thalamus were positively correlated with WM-LV(r=0.620,r=0.671,r=0.558,all P<0.01),the FA and MD values of the remaining nuclei and the QSV of each nucleus were not significantly correlated with WM-LV(all P>0.05);the EDSS score was significantly negatively correlated with QSV of the thalamus(rs=-0.370,P=0.019).Conclusions:In relatively early RRMS,the deep gray matter is significantly atrophy,accompanied by microstructure damage and iron disorders,which partly independent of the focal demyelination of white matter;the involvement of the thalamus is an essential feature of RRMS and its iron concentration may be a marker of disease severity in MS to monitor disease progression.