定量磁化率成像对多发性硬化患者颅内铁沉积的初步研究

Preliminary study on intracranial iron metabolism in patients with multiple sclerosis using MR quantitative susceptibility mapping

目的:采用定量磁化率成像(QSM)方法观察多发性硬化(MS)患者病灶性质以及正常表现白质区域(NAWM)、灰质核团区域磁化率改变情况。方法:分别采集23例MS患者与9名正常志愿者的QSM数据,独立样本t检验进行患者组与对照组之间灰质核团、NAWM磁化率的差异分析,并采用Spearman相关分析观察患者组的灰质核团、病灶平均磁化率、病灶总负荷及各临床指标之间的相关性。结果:病灶主要表现为结节状高信号、环形高信号及等信号。MS患者组与对照组在NAWM区域的磁化率平均值的差值存在差异(P<0.05),而在各灰质核团的磁化率平均值的差值无显著统计学差异。患者组的病灶平均磁化率与壳核、齿状核的磁化率存在正相关(P<0.05),患者组的病灶总负荷及病程与苍白球、丘脑、红核的磁化率存在正相关(P<0.05)。扩展残疾状态量表评分与病灶平均磁化率及各灰质核团的磁化率均没有相关性。结论:QSM可用于MS患者颅内铁含量的定量检测,同时能为无强化病灶的活动性判断提供较宽的时间窗。MS患者颅内的NAWM存在潜在的病理生理学异常。

Objective To apply quantitative susceptibility mapping(QSM) for observing the characteristics of the lesions and the changes in the magnetic susceptibility of normal-appearing white matter(NAWM) and gray matter nuclei in patients with multiple sclerosis(MS). Methods The QSM data of 23 MS patients and 9 normal controls were collected. The differences in the magnetic susceptibility of NAWM and gray matter nuclei between MS patients and normal controls were analyzed with independentsamplest test. The correlations among gray matter nuclei, mean magnetic susceptibility of lesions, total lesion load and clinical indicators of MS patients were investigated by Spearman correlation analysis. Results Three types of MS plaques were observed,including nodular hyperintense, annular hyperintense and isointense. Statistical differences were found in the mean magnetic susceptibility of NAWM between MS patients and normal controls(P<0.05), but not in the mean magnetic susceptibility of gray matter nuclei. The mean magnetic susceptibility of lesions was positively correlated with the magnetic susceptibility of putamen and dentate nuclei(P<0.05). The total lesion load had a positive correlation with the magnetic susceptibility of pallidus, thalamus and red nuclei(P<0.05). The expanded disability status scale score had no correlation with mean magnetic susceptibility of lesions and the magnetic susceptibility of gray matter nuclei. Conclusion QSM can be used for the quantitative detection of intracranial iron content in MS patients, providing a wider time window for determining the activity of non-enhanced lesions. MS patients have potential pathophysiological abnormalities in intracranial NAWM.