药物过度使用性头痛患者脑内铁沉积分布的定量磁敏感成像研究

Brain iron deposition increases in the bilateral substantia nigra of patients with medication-overuse headache:a quantitative susceptibility mapping analysis

目的运用定量磁敏感成像(QSM)技术研究药物过度使用性头痛(MOH)患者脑内铁沉积分布特点,并探索其神经机制。方法37名MOH患者和21名健康志愿者进行相同的大脑多回波梯度回波序列及高分辨率结构成像采集。采用基于体素的方法分析脑内铁沉积变化,提取出阳性脑区定量磁敏感值,最后将磁敏感值与临床变量进行相关性分析。结果与健康志愿者相比,MOH患者脑内铁沉积增加的脑区主要为双侧黑质(MNI坐标:8,-18,-14;-6,-16,-14,P<0.001),然而黑质增加的磁敏感值与临床变量无统计学相关意义(P>0.05)。左侧黑质曲线下面积为0.734,截断值为0.077,灵敏度为72.97%,特异性为70.37%;右侧黑质曲线下面积为0.699,截断值为0.084,敏感性为72.97%,特异性为62.96%。结论MOH患者脑内双侧黑质内铁沉积水平增加,这可能为MOH中脑边缘多巴胺系统的功能障碍机制提供新的研究思路,但MOH的病理生理机制还需要进一步研究证实;同时,QSM技术可作为检测MOH中脑铁沉积变化的无创性且有效的定量工具。

Objective To investigate iron accumulation level over the whole brain and explore the possible neuromechanism of medication-overuse headache(MOH)using quantitative susceptibility mapping(QSM).Methods Thirty-seven MOH patients and 27 normal control subjects were enrolled in the study for examinations with both a multi-echo gradient echo magnetic resonance(MR)sequence and brain high resolution structural imaging.Avoxel-based analysiswas performed to detect the brain regions with altered iron deposition,and the quantitative susceptibility mapping values of the positive brain regions were extracted.Correlation analysis was performed between the susceptibility values and the clinical variables of the patients.Results In patients with MOH,increased susceptibility values were found mainly in the bilateral substantia nigra(SN)(MNI coordinate:8,-18,-14;-6,-16,-14)as compared with the normal control subjects(P<0.001),but these alterations in iron deposition were not significantly correlated with the clinical variables of the patients(P>0.05).The susceptibility value in the left SN had an area under curve(AUC)of 0.734,and at the cut-off value of 0.077,its diagnostic sensitivity was 72.97%and its specificity was 70.37%for distinguishing MOH from normal controls;The susceptibility value in the right SN had an AUC of 0.699 with a diagnostic sensitivity of 72.97%and a specificity of 62.96%at the cut-off value of 0.084.Conclusion Increased iron deposition occurs in the bilateral SN of MOH patients,which provides a new insight into the mechanism of mesocorticolimbic dopamine system dysfunction in MOH.QSM technique can be used as a non-invasive means for quantitative analysis of brain iron deposition in migraine neuroimaging.