基于纤维束空间统计学分析视神经脊髓炎谱系疾病脑白质微结构改变

Evaluation on changes of white matter microstructure in neuromyelitis optica spectrum disorders with tract-based spatial statistics

目的采用DTI基于纤维骨架空间统计方法(TBSS)分析视神经脊髓炎谱系疾病(NMOSD)患者脑白质纤维束微结构的改变。方法对20例NMOSD患者(NMOSD组)和20名健康志愿者(正常对照组)行全脑常规MR和DTI扫描,使用FSL软件包中TBSS步骤对DTI数据行全脑非参数统计分析,并对NMOSD组有统计学差异的纤维束FA值与临床扩展残疾状态量表(EDSS)评分进行相关性分析。结果与正常对照组比较,NMOSD组大脑及小脑白质区纤维束如胼胝体、穹隆、皮质脊髓束、钩束、小脑脚等广泛FA值减低(P<0.05,FEW校正),其中扣带束、胼胝体、穹隆等AD值减低、RD值增高,穹隆和左侧内囊豆核后部MD值升高(P<0.05,FEW校正)。NMOSD患者左侧钩束、右侧外囊、左侧小脑下脚及双侧内囊前肢、内侧丘系FA值与EDSS评分呈负相关(P均<0.05)。结论 TBSS显示NMOSD患者大脑及小脑存在广泛脑白质损伤,可解释NMOSD部分临床症状,与残疾症状无关的脑区纤维束微结构改变提示NMOSD患者这些区域病变可能存在更复杂的病理机制。

Objective To assess the changes of white matter microstrueture in neuromyelitis optica spectrum disorders （NMOSD） with DTI based on tract-based spatial statistics （TBSS） method. Methods Conventional MR and DTI were performed in 20 NMOSD patients （NMOSD group） and 20 healthy volunteers （control group）. DTI data were analyzed with TBSS procedure, which was a part of FSL software packages, and no.parametric statistical analysis was performed on the whole brain. Correlation between FA value of tracts with significant difference in NMOSD group and expanded disability status sca[e （EDSS） scores was analyzed. Results TBSS analysis revealed sigrd{ieantly （P〈0.05, FWE corrected） extensive decrease of FA value in cerebrum and cerebellum white matter fiber bundles, i.e. corpus callosum, fornix, corticospinaI tract, unciform fasciculus, cerebellar peduncles etc. in NMOSD group, and decrease of AD value, increase of RD value in cingulum bundle, corpus callosum and fornix, while MD value only increased in fornix and retrolentieular part of the left internal capsule （P〈0.05, FWE corrected）. Negative correlations were found between FA value of left uncinate fasciculus, right external capsule, left inferior cerebellar peduncle, bilateral anterior limb of internal capsule, medial lemniscus and EDSS scores （all P〈0.05）. Conclusion Widespread white matter damage is observed in cerebrum and cerebellum in NMOSD patients by using TBSS analysis, which may partly correspond to the disabilities of NMOSD patients. However, the other microstructural changes of white matter tracts may suggest complicated pathological mechanism of NMOSD.