磁共振扩散张量成像在不同时期急性缺血性脑梗死鉴别中的应用价值研究

Application Value of DTI in Identifying Acute Ischemic Cerebral Infarction at Different Stage

背景急性缺血性脑梗死(AICI)是临床急危重症,不同时期AICI的治疗方案不同,但临床对AICI不同时期的鉴别缺乏客观依据。目的探究磁共振扩散张量成像(DTI)在不同时期AICI鉴别中的应用价值,以为临床医生合理制定个体化治疗方案提供参考依据。方法选取2018年3月至2021年8月在中国人民解放军海军安庆医院神经内科就诊的AICI患者52例,根据发病时间将其分为超急性期(<6 h)13例、急性期(≤3 d)25例和亚急性期(4~10 d)14例。比较不同时期AICI患者梗死灶与梗死灶对侧、梗死灶旁与梗死灶旁对侧DTI各参数〔包括平均弥散系数(DCavg)、各向异性指数(FA)、各向同性(ISO)、容积比各向异性(VRA)及衰减指数(Exat)〕,比较不同时期AICI患者DTI各参数相对值。结果超急性期、急性期及亚急性期AICI患者梗死灶DCavg分别低于梗死灶对侧,ISO、Exat分别高于梗死灶对侧(P<0.05);急性期及亚急性期AICI患者梗死灶FA、VRA分别低于梗死灶对侧(P<0.05)。急性期、亚急性期AICI患者梗死灶旁DCavg分别低于梗死灶旁对侧,ISO分别高于梗死灶旁对侧(P<0.05)。不同时期AICI患者梗死灶旁Exat分别高于梗死灶旁对侧(P<0.05)。急性期及亚急性期AICI患者梗死灶FA、VRA相对值低于超急性期AICI患者,ISO相对值高于超急性期AICI患者(P<0.05)。AICI超急性期患者梗死灶在DTT DCavg图上显示信号减低,在DTT FA图上显示信号无明显改变;急性期AICI患者梗死灶在DTT DCavg图及FA图上显示信号均减低,白质纤维束破坏、中断;亚急性期AICI患者梗死灶在DTT DCavg图及FA图上可见白质纤维束明显中断、减少。结论DCavg、FA、VRA、ISO及Exat在不同时期AICI中存在一定变化规律,在AICI急性期、亚急性期梗死灶旁脑组织水分子扩散受限,FA、ISO、VRA相对值对超急性期与急性期、亚急性期AICI具有一定鉴别诊断价值,DTI有助于临床判断发病时间不明确的AICI患者。

Background Acute ischemic cerebral infarction(AICI)is a clinically critical illness,its treatment programs are different in different stage,and there is no objective basis for the clinical identification of AICI in different stage.Objective To study the application value of magnetic resonance diffusion tensor imaging(DTI)in identifying AICI at different stage,so as to provide reference basis for clinicians to reasonably formulate individualized treatment plans.Methods A total of 52 patients with AICI treated in the Department of Neurology,the PLA Navy Anqing Hospital from March 2018 to August 2021 were selected.According to the time of onset,they were divided into 13 cases in hyperacute stage(<6 hours),25 cases in acute stage(≤3 days)and 14 cases in subacute stage(4-10 days).The parameters of DTI[including average diffusion coefficient(DCavg),fractional anisotropy(FA),isotropic image(ISO),volume ratio anisotropy(VRA)and exponential attenuation(Exat)]in patients with AICI at different stages were compared,and the relative values of DTI parameters of infarct focus and near infarct focus in patients with AICI at different stages were compared.Results DCavg of infarct focus in patients with hyperacute stage,acute stage and subacute stage AICI were lower than that of contralateral to infarct focus,respectively,ISO and Exat were higher than those of contralateral to infarct focus,respectively(P<0.05);FA and VRA of infarct focus in patients with acute stage,subacute stage AICI were lower than those of contralateral to infarct focus,respectively(P<0.05).In patients with acute stage,subacute stage AICI,DCavg of near infarct focus was lower than that of contralateral to infarct focus,respectively,and ISO was higher than that of contralateral to infarct focus,respectively(P<0.05).The Exat of near infarct focus was higher than that of contralateral to infarct focus in patients with AICI at different stages,respectively(P<0.05).The relative values of FA and VAR of infarct focus in patients with acute stage,subacute stage AICI were lower than those in patients with hyperacute stage AICI,and the relative value of ISO of infarct focus was higher than that in patients with hyperacute stage AICI(P<0.05).In patients with hyperacute stage AICI,the signal of infarct decreased on DTT DCavg,but there was no significant change on DTT FA.In patients with acute stage AICI,the signal of infarct decreased on DTT DCavg and FA,and the white matter fibers were destroyed and interrupted.In patients with subacute stage AICI,white matter fibers were significantly interrupted and reduced on DTT DCavg and FA.Conclusion The parameters of DTI such as DCavg,FA,VRA,ISO and Exat have certain changes in AICI with different periods.The diffusion of water molecules in the brain tissue near infarct is limited in the patients with acute stage,subacute stage AICI.The relative values of FA,ISO and VRA have certain differential diagnostic value for patients with hyperacute stage,acute stage and subacute stage AICI.DTI is helpful to judge the patients with AICI whose onset time is not clear.