新生儿缺氧缺血性脑病中扩散张量成像对脑白质损伤及预后的诊断价值

  目的  分析扩散张量成像（DTI）在新生儿缺氧缺血性脑病诊断中对脑白质的损伤和预后的价值。  方法  将本院于2018年8月~2021年6月收治的60例行MRI检查的新生儿作为研究对象，年龄均 < 2周岁，且均有缺氧缺血性脑病史。将患者分为脑瘫组和非脑瘫组（30例/组），记录其常规颅脑平扫征象和得分，于DTI图像上找出感兴趣区域并测定各向异性分数（FA）值和表观弥散系数（ADC）值。测定的白质区包括:内囊前肢、丘脑后辐射、额叶白质、中脑大脑脚、胼胝体压部、下纵束、胼胝体体部、内囊后肢、视辐射、内囊膝部、皮质脊髓束、半卵圆中心、听辐射、胼胝体膝部和顶叶白质等。生成胼胝体纤维束和皮质脊髓束的三维图像。对比分析两组患儿平扫的征象和FA值与ADC值；采用Logistic回归分析多因素筛选脑白质损伤的独立影响因素，并评估其拟合度和效能。  结果  经MRI平扫，两组患儿颅脑左侧的丘脑、两侧的半卵圆中心区和胼胝体体部的征象差异具有统计学意义（P < 0.05）；其中脑瘫组患儿各个部位的FA值均比非脑瘫组小，且两组患儿的FA值在内囊后肢、听辐射、双侧中脑大脑脚、视辐射、顶叶白质、皮质脊髓束、胼胝体压部、下纵束、半卵圆中心、胼胝体膝部、丘脑后辐射、胼胝体体部和左侧豆状核的差异具有统计学意义（P < 0.05）；两组患儿的ADC值在双侧半卵圆中心、胼胝体体部、左侧内囊后肢、左侧丘脑后辐射、双侧皮质脊髓束、左侧顶叶及压部和左侧丘脑差异具有统计学意义（P < 0.05）；左侧内囊后肢、胼胝体压部和左侧皮质脊髓束的FA值可作为脑白质损伤的独立预测因素，三者联合用于缺氧缺血性脑病患儿脑白质损伤的ROC AUC是0.887，特异性和敏感度分别是90.38% 和85.12%，准确度为0.761。  结论  缺氧缺血性脑病会使其白质纤维束发生损伤，使其FA值降低，ADC值升高，DTI可明确反映出患儿神经纤维束发育和受损的程度，可作为缺氧缺血性脑病的诊断和预后依据。 

Value of diffusion tensor imaging in the diagnosis and prognosis of neonatal hypoxic-ischemic encephalopathy

  Objective  To explore the value of diffusion tensor imaging (DTI) in the diagnosis of cerebral white matter injury and prognosis of neonates with hypoxic-ischemic encephalopathy.  Methods  Sixty neonates undergoing MRI examination admitted to our hospital from August 2018 to June 2021 were selected as the research subjects. All patients were younger than 2 years old and had a history of hypoxic-ischemic encephalopathy. The patients were divided into two groups, the signs and scores of conventional craniocerebral scans were recorded. The regions of interest were identified on DTI images, the values of FA and ADC were measured. The measured areas of white matter including forelimbs of the internal capsule, craniocerebrum of the midbrain, hind limbs of the internal capsule, knee of the internal capsule, corticospinal tract, center of half ovale, retrothalamic radiation, inferior longitudinal tract, auditory radiation, visual radiation, corpus callosum body, knee of the corpus callosum, frontal white matter, pressure of the corpus callosum, and white matter of the parietal lobe. Three-dimensional images of the fibrous tracts of the corpus callosum and the corticospinal tracts were produceded. The plain scan signs, FA values and ADC values of the two groups were compared and analyzed. The independent influencing factors of white matter injury was screened by multivariate logistic regression analysis, the fitting degree and effectiveness were evaluated.  Results  Brain MRI plain scan showed significant differences in the signs of left thalamus, bilateral center of semi- ovale and corpus callosum between the two groups (P < 0.05). The FA value of each part of the group of children with cerebral palsy were smaller than the cerebral palsy group, sac and FA values of two groups of children, hind legs, bilateral middle cerebral cerebral peduncle, corticospinal tract, half egg circle center, thalamus after radiation, the longitudinal fasciculus, listen to the radiation, radiation, corpus callosum knee, parietal white matter, corpus callosum, the body and the left side of the corpus callosum lentiform nucleus have significant difference (P < 0.05). There were significant differences in ADC values between the two groups in bilateral semi-ovale center, left posterior limb of internal capsule, left posterior thalamic radiation, bilateral corticospinal tract, left parietal lobe, corpus callosum body part and compression part, and left thalamus (P < 0.05). Multivariate regression showed that the FA values of the left posterior limb of the internal capsule, the left cortical cord and the corpus callosum were independent predictors of white matter injury. The ROC AUC of the three factors combined in the treatment of white matter injury in children with hypoxic- ischemic encephalopathy was 0.887, the specificity and sensitivity were 90.38% and 85.12% respectively, and the accuracy was 0.761.  Conclusion  Hypoxic-ischemic encephalopathy can damage the white matter fiber bundles, decrease the FA value and increase the ADC value. DTI can clearly reflect the development and damage degrees of the nerve fiber bundles in children, which can be used as the diagnosis and prognosis basis of hypoxic-ischemic encephalopathy.