磁共振成像及CT在急性缺血性脑卒中的诊断价值

Clinical study on MRI and CT findings of acute ischemic stroke and the diagnostic value

目的研究急性缺血性脑卒中(AIS)患者磁共振成像(MRI)、CT表现及其诊断价值。方法选取2016年5月至2018年5月我院收治的AIS患者84例为研究对象,均行MRI[反转恢复序列(FLAIR)、弥散加权像(DWI)、磁共振血管成像(MRA)]及CT检查,分析其影像特点、影像参数[表观扩散系数(ADC)、脑血流量(CBF)、脑血容量(CBV)、达峰时间(TTP)]及不同发病时间段2种检查方法对病灶检出率,绘制ROC曲线评估MRI、CT对AIS早期病变的诊断价值。结果84例AIS患者中,CT可见豆状核轮廓模糊,岛带低密度,灰白质分界不清,皮质低密度,脑沟、脑裂变窄,DWI表现为大脑中动脉(MCA)供血区高信号影,ADC值低信号,其中MCA高密度征、大脑中动脉点征、近端高信号血管征、远端高信号血管征、血管磁敏感征、病灶周围软脑膜血管阳性率分别为37%(31/84)、22%(22/84)、69%(58/84)、83%(70/84)、89%(75/84)、81%(68/84);与健侧相比,缺血病灶ADC值、CBF、CBV下降,TTP延长(P<0.05);发病<6h、6~12h时间段,MRI对AIS检出率高于CT(P<0.01),而13~24h时间段2种方法对AIS检出率比较差异无统计学意义(P>0.05);MRI诊断早期(发病时间<6h)AIS的灵敏度、特异度、准确度高于CT(P<0.05)。结论AIS患者的MRI及CT均有一定的影像特征,其中MRI诊断价值更高,尤其对早期AIS检出率高于CT,值得在临床推广实践。

Objective To study the MRI,CT findings of patients with acute ischemic stroke(AIS)and the diagnostic value.Methods Eighty four patients with AIS admitted to the hospital from May 2016 to May 2018 were enrolled in the study.All patients underwent MRI(FLAIR,DWI,MRA)and CT examinations.The imaging characteristics,imaging parameters[apparent diffusion coefficient(ADC),cerebral blood flow(CBF),cerebral blood volume(CBV),time to peak(TTP)]and the detection rate of lesions at different onset periods with the two detection methods were analyzed.ROC curve was draned to evaluate MRI,CT for early lesions of AIS diagnostic value.Results In 84 patients with AIS,CT showed a blurred outline of the lenticular nucleus,low density of the island zone,unclear demarcation between gray matter and white matter,low density of the cortex,narrow sulci and schizencephaly.DWI showed high signal shadow of the blood supply area in the middle cerebral artery(MCA),low signal of ADC value.The positive rates of hyperdense middle cerebral artery sign,middle cerebral artery dot sign,proximal high signal vascular sign,distal high signal vascular sign,vascular magnetic sensitization and the peridural blood vessels around the lesions were 37%(31/84),22%(22/84),69%(58/84),83%(70/84),89%(75/84)and 81%(68/84),respectively.Compared with the contralateral position,the ADC value,CBF,CBV of the ischemic lesion decreased,the TTP prolonged(P<0.01).The detection rate of AIS by MRI was higher than by CT in the condition of onset time less than 6 h and 6 to 12 h(P<0.01).There was no significant difference in the detection rate of AIS between the two methods in the period from 13 to 24 h(P>0.05).The sensitivity,specificity and accuracy for the early AIS(onset time less than 6 h)by MRI were higher than those by CT(P<0.05).Conclusion MRI and CT of AIS patients have certain imaging features.MRI has higher diagnostic value,especially for the early detection of AIS,which was higher than that by CT.