MRI信号强度比联合扩散张量成像定量分析缺血性脑卒中大鼠髓鞘早期结构改变的研究  

Quantitative analysis of early changes in the myelin structure of rats with ischemic stroke using MRI signal intensity ratio and diffusion tensor imaging

作　　者：翁娜 邵翠杰[2] 李国栋 宾莉 黄丹琪 王旭[1] WENG Na;SHAO Cuijie;LI Guodong;BIN Li;HUANG Danqi;WANG Xu(Department of Nuclear Medicine,Binzhou Medical University Hospital,Binzhou 256600,China;Medical Research Center,Binzhou Medical University Hospital,Binzhou 256600,China)

机构地区：[1]滨州医学院附属医院核医学科,滨州256600 [2]滨州医学院附属医院医学研究中心,滨州256600

出　　处：《磁共振成像》2022年第10期150-156,共7页Chinese Journal of Magnetic Resonance Imaging

基　　金：国家自然科学基金(编号:81771828)。

摘　　要：目的探讨7.0 T MRI的信号强度比(signal intensity ratio,SIR)联合扩散张量成像(diffusion tensor imaging,DTI)对缺血性脑卒中大鼠的白质髓鞘损伤的诊断价值。材料与方法SD大鼠18只随机分成A、B、C三组,每组6只,A组进行大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)假手术,暴露颈部血管而不结扎;B组为MCAO术后24 h组;C组为MCAO术后72 h组。相同条件下进行T1WI、T2WI、DTI扫描,后处理得到SIR、各向异性分数(fractional anisotropy,FA)、表观扩散系数(apparent diffusion coefficient,ADC)、垂直扩散张量(radial diffusivity,D_(⊥))图像,勾画胼胝体和外囊区域进行计算SIR值、FA值、ADC值和D_(⊥)值,并进行三组间单因素方差分析。扫描结束后取材进行劳克坚牢蓝(luxol fast blue,LFB)-焦油紫病理染色,测量平均灰度值(mean grayscale value,MGSV)后进行3组间单因素方差分析。将差异具有统计学意义的影像学数据和病理学平均灰度值进行两两相关性分析。结果与A组相比,B组外囊区域的SIR值(P=0.044)、FA值(P=0.001)、ADC值(P=0.001)、D_(⊥)值(P=0.001)降低;C组外囊区域SIR值(P<0.001)、FA值(P=0.002)降低;胼胝体区域SIR值(P=0.031)、FA值(P=0.015)降低。LFB-焦油紫病理染色在脑卒中受损区域髓鞘着色较差,MGSV降低(P<0.05)。在外囊区域,MGSV与SIR值(P<0.0001)、FA值(P≤0.0001)、ADC值(P=0.0127)、D_(⊥)值(P=0.0180)呈负相关。在胼胝体区域,MGSV与SIR值(P=0.0018)呈负相关。结论SIR和DTI的联合使用作为一种评估缺血性脑卒中多阶段髓鞘损伤的无创影像学方法,在大鼠实验中得到有效验证,为临床诊治提供影像学思路。Objective:To explore the early diagnostic value of signal intensity ratio(SIR)and diffusion tensor imaging(DTI)in myelin structural changes in the white matter of ischemic stroke rats.Materials and Methods:Eighteen Sprague Dawley rats were divided into three groups,Groups A,B,and C,with six rats in each group.Middle cerebral artery occlusion(MCAO)sham operation without ligation was performed in group A,the 24 hours after MCAO operation in group B,and the 72 hours after MCAO operation in group C.After obtaining T1WI,T2WI,and DTI scans under the same conditions,post-processing to get the SIR,fractional anisotropy(FA),apparent diffusion coefficient(ADC),radial diffusivity(D_(⊥))imaging.The corpus callosum and external capsule regions were outlined to calculate the SIR value,FA value,ADC value,and D_(⊥)value,and a one-way analysis of variance was performed among the three groups.At the end of scanning,the samples were obtained for luxol fast blue(LFB)-tar purple pathological staining,and the mean grayscale value(MGSV)was measured.One-way analysis of variance between the three groups was performed.Pairwise correlation analysis was performed between the statistically significant imaging data and the MGSV.Results:Compared with group A,group B had decreased SIR(P=0.044),fractional anisotropy(FA;P=0.001),apparent diffusion coefficient(ADC;P=0.001)and radial diffusion coefficient(D_(⊥);P=0.001)values in the external capsule region.Group C had decreased SIR(P<0.001)and FA(P=0.002)in the external capsule region.SIR(P=0.031)and FA(P=0.015)in the corpus callosum were decreased.LFB-tar purple poorly stained the areas of the myelin sheath that were damaged due to stroke,and the mean grayscale value(MGSV)decreased(P<0.05).In the external capsule region,MGSV was negatively correlated with SIR(P<0.0001),FA(P≤0.0001),ADC(P=0.0127),and D_(⊥)(P=0.0180).In the corpus callosum region,MGSV was negatively correlated with SIR(P=0.0018).Conclusions:A combination of SIR and DTI can be used as a noninvasive imaging method to evaluat

关 键 词：缺血性脑卒中 脱髓鞘 MCAO模型 信号强度比 磁共振成像 扩散张量成像 

分 类 号：R445.2[医药卫生—影像医学与核医学] R-332[医药卫生—诊断学]