临床孤立综合征和复发缓解型多发性硬化患者表现正常脑白质及脑灰质的MR扩散张量直方图比较

A comparative study of MR diffusion tensor imaging histogram between clinically isolated syndrome and relapsing-remittlng multiple sclerosis in normal appearing white matter and grey matter

目的评价扩散张量成像（DTI）对临床孤立综合征（CIS）的研究价值，了解CIS的病理变化机制及与复发缓解型多发性硬化（RRMS）的关系。方法选择19例CIS患者（CIS组）、19例RRMS患者（RRMS组）和19例性别、年龄与之匹配的健康志愿者（正常对照组）为研究对象。用1．5T超导型MR机采集数据，经图像后处理得到表现正常脑白质（NAWM），表现正常脑灰质（NAGM）的平均扩散率（MD）、各向异性分数（FA）直方图，其中提取出下列指标：平均值、直方图峰高和峰位置，进行单因素方差分析和秩和检验，并对3组NAWM、NAGM的MD、FA值与扩展残疾状态量表（EDSS）评分进行Spearman相关分析。结果RRMS组患者表现正常脑白质MD为（0．83±0．04）×10^-3mm^2／s，较正常对照组（0．78±0．02）×10^-3mm^2／s、CIS组（0．79±0．02）×10^-3mm^2／s均显著增高（F=15．304，P〈0．01），但CIS组与正常对照组间差异无统计学意义（P〉0．05）；MD图峰高CIS组明显低于正常对照组（P〈0．01）；RRMS组平均FA值（0．36±0．03）较正常对照组（0．41±0．01）及CIS组（0．40±0．02）均降低（F=17．965，P〈0．01），但CIS组与正常对照组间差异无统计学意义（P〉0．05），平均FA图峰位置CIS组较正常对照组明显左移。NAGMMD在正常对照组、CIS组、RRMS组分别为（1．03±0．05）、（1．08±0．06）、（1．18±0．12）×10^-3mm^2/s，依次增高，且差异均有统计学意义（F=15．261，P〈0．01）。CIS患者的各项DTI指标与EDSS评分均无显著性相关。RRMS患者NAGM的MD与EDSS评分呈正相关（r=0．568，P〈0．05）。结论DTI直方图可以敏感的显示及量化CIS及多发性硬化（MS）NAWM、NAGM的异常，作为MS最早期表现的CIS患者NAWM、NAGM均已发生了病理改变，但较MS病变轻。

Objective To investigate whether abnormalities can be detected in normal-appearing white matter （NAWM） and normal-appearing grey matter （NAGM） in patients with clinically isolated syndrome （CIS） and comparing them to the abnormalities in relapsing-remitting multiple sclerosis （RRMS） by using diffusion tensor imaging （DTI） histogram. To detect the potential relationship between DTI indices of NAWM, NAGM and patient＇s clinical condition. Methods Nineteen patients with CIS, 19 clinically diagnosed RRMS patients and 19 sex- and age-matched healthy volunteers were included in this study. Conventional MRI and DTI images were obtained using Siemens 1.5 T Magnetom sonata scanner. DTI histograms of NAWM and NAGM were obtained after post-processing. The mean value, peak height, peak location of the histogram were used for analysis. All data was statistically processed with SPSS for Windows. Results NAWM average MD was higher and FA was lower in RRMS[ MD （0. 83 ±0.04） × 10^-3mm-2/s, FA 0. 36 ±0.03]when compared to CIS[ MD （0. 79 ±0.02） × 10^-3mm^2/s,FA 0.40 ±0. 02] and control [ MD （0. 78 ±0. 02） × 10^-3mm^2/s,FA 0. 41 ±0. 01 ] （P 〈0. 01 ）. But no statistically significant difference was found between CIS and control. The peak height of NAWM average MD histogram was significantly lower in CIS than control （P 〈 0. 05 ）, while the peak location of average FA histogram shifted to the left （ P 〈 0. 01 ）. Patients with CIS [ （ 1.08 ±0. 06） ×10^-3mm^2/s] showed significantly higher NAGM average MD than control [ （ 1.03 ± 0.05 ） × 10^-3 mm^2/s ] （ p 〈 0.05 ）, but, lower than RRMS [ （ 1.18 ±0. 12 ）× 10^-3mm^2/s] （P 〈0. 01 ）. There were no correlation between DTI indices and EDSS scores in patients with CIS. Moderate correlation between NAGM average MD （r =0. 568 ,P 〈0.05 ） and EDSS scores were found in patient with RRMS. Conclusion NAWM and NAGM abnormalities do occur in CIS which can be detected by DTI. The underlying pathological changes in NAWM and NAGM in CIS may be milder than RRMS as demonstrated by DTI histogram.