磁共振波谱与扩散张量成像联合评价皮质下血管性认知功能障碍左丘脑损害

Evaluation on the lesion in theleft thalamusin patients with subcortical vascular congnitive impairment using 1H magnetic resonance spectroscopy and diffusion tensor imaging.

目的应用1H-磁共振波谱(1H Magnetic resonance spectroscopy,1H-MRS)及扩散张量成像(diffusion tensor imaging,DTI)技术联合评价皮质下缺血性脑血管病(subcortical ischemic vascular disease,SIVD)认知障碍患者左丘脑损害,探讨其与执行功能的关系。方法对SIVD中14例血管性痴呆(vascular dementia,VaD)患者、14例血管性无痴呆型认知损害(vascular cognitive impairment no dementia,VCIND)患者及14例健康老年人行连线测验(trail making test,TMT)等神经心理评估,应用1H-MRS采集左丘脑感兴趣区(regions of interest,ROI)N-乙酰天门冬氨酸(NAA)、胆碱(Cho)、肌醇(MI)及肌酸(Cr)浓度,计算NAA/Cr、Cho/Cr及MI/Cr比值。同时进行DTI扫描,测定与1H-MRS所选ROI相同的左丘脑的部分各向异性分数(fractional anisotropy,FA)及平均扩散度(mean diffusivity,MD),进一步分析其与TMT时间的关系。结果与正常对照组比较,VaD组、VCIND组左丘脑NAA/Cr降低(F=3.656,P=0.038),SIVD组两组比较无明显差别(P﹤0.05);VaD、VCIND组患者左丘脑MD值较正常对照组升高(F=3.882,P=0.030),病例组两组间无明显统计学差异(P﹤0.05);左丘脑NAA/Cr、MI/Cr、Cho/Cr与同区域的FA及MD值均无明显相关(P﹤0.05);左丘脑Cho/Cr与TMTb明显正相关(r=0.520,P=0.001),MD值与TMT b呈正相关(r=0.305,P=0.044)。结论1H-MRS与DTI结合能更好地检测出丘脑可能存在的隐匿性损伤;左丘脑Cho/Cr与MD值与执行功能相关。

Objective To investigate the lesionsin theleft thalamus and to explore their correlation with executive functionin patients with subcortical ischemic vascular disease （SIVD）by using 1H magnetic resonance spectroscopy （1H-MRS） and diffusion tensor imaging （DTI）. Methods Fourteen patients with vascular dementia （VaD）, 14 patients with vascular cognitive impairment without dementia（VCIND）and 14 normal controls （NC） were recruited. The quantitative analysis of N-acetylaspartate （NAA）, Choline （Cho）, myoinositol （MI） and Creatine （Cr） resonance signals in region of in- terests （ROI） in the left thalamus were measured. Fractional anisotropy （FA） and mean diffusivity （MD） values in the same region were examined by using DTI. The relationship were analyzedamong the MRS, DTI ratios and cognitive impairment reflected in MMSE and trail making test（TMT）. Results The NAA/Cr ratio showed a gradual decrease in the left thala- mus of VaD andVCIND patients compared with controls （F=3.656, P=0.038）. There was no significant difference in NAA/Cr ratiobetween VaD and VCIND patients.Compared with controls, patients with VaD and VCIND demonstrated in- creased MD value in the left thalamus （F=3.882, P=0.030）.There was no significant difference in MD value between VaD and VCIND patients （P〉O.05）. There were no correlations between NAA/Cr, MI/Cr, Cho/Cr value and DTI parame- ters in the ROI（P〉0.05）. TMTb time was positively associated with Cho/Cr （r=0.520, P=0.001 ） and with MD value in the left thalamus （r=0.305, P=0.044）. Conclusions Combination of 1H-MRS with DTI can provide the valuable informa- tionon the potential lesions in the thalamus in patients with SIVD. The Cho/Cr and MD values in the leftthalamus may be correlated with executive function.