To Study The Application Value Of B-mode Ultrasound In Preterm Infants With Brain Injury

Research backgroundPremature infants are a special group of newborn, because each organ development is not mature, the compensatory ability of the body, the mortality and incidence of sequelae was higher than that of full-term infants. With the improvement of medical conditions and medical technology improves, premature mortality rate reduced year by year, preterm very low birth weight infants and extremely low birth weight infant survival rate is greatly increased, But the sequelae of nervous system did not decrease proportionally, of which about10%have some degree of cerebral palsy (CP),25%～50%showed mild neurodevelopment disorders, related to motion, cognition and behavior, thus cause learning disabilities. Premature infant brain development is not mature, has the features of easy damage, perinatal hypoxia ischemia, infection risk factors lead to a lot of inflammatory factors, activation of excitatory amino acid accumulation, the release of oxygen free radicals, prone to premature infants with brain injury. The prevalence of CP in epidemiological survey results in different countries or regions are not the same, The prevalence rate of developed countries with CP was1.8‰-4.9‰, more concentrated in between.2‰～3‰.The United States was born a year of63000premature infants weighing less than1500g,10%-15%and other movement disorders of CP,25%～50%of cognitive disorders of nervous system sequelae. Our country shows massive cerebral palsy epidemiology investigation in1997, the prevalence rate of CP was1.2‰-2.7%o in the1～7years old children, is one of main diseases in children with physical disabilities. There is no evidence that there are local variations in children with CP. CP etiology has the diversity and complexity. Retrospective treatment showed, birth abnormalities such as premature birth, low birth weight, perinatal asphyxia (including intrauterine asphyxia and birth asphyxia) accounted for40%,36%and40%respectively,postnatal hypoxic ischemic encephalopathy, intracranial hemorrhage, intracranial infection and nuclear jaundice accounted for20%,12%,4%, and2%, unknown causes account for20%. Thus, premature birth, low birth weight, perinatal asphyxia is the main cause of CP.CP bring heavy burden to patients, families and society the brain injury in preterm infants, has become a major public health problem, the brain injury in preterm infants, such as periventricular-intraventricular hemorrhage (PIVH), cerebral white matter damage (WBD) and periventricular leukomalacia (PVL), hypoxic ischemic encephalopathy (HIE), the research has become a research focus of medical around.Premature infants with acquired brain injury usually include bleeding and non hemorrhagic injury two, hemorrhagic injury is common in PIVH, intracerebral hemorrhage (IPH), subarachnoid hemorrhage (SAH), subdural hemorrhage (SDH), cerebellar hemorrhage (ICH) bleeding and other parts of the body; non hemorrhagic injury mainly for WBD. The characteristics of brain damage in preterm infants include WBD, PIVH and various types of nerve damage, in recent years with IVH reduces the incidence of, periventricular white matter injury, including PVL and periventricular hemorrhagic infarction (PHI), has become the main type of brain injury in preterm infants. PIVH is the most common type of hemorrhage of premature infant brain injury, incidence rate can be as high as60%-70%, in various types of intracranial hemorrhage in newborn, accounting for about85%-90%. PIVH is the harm caused brain damage, such as obstructive hydrocephalus, cerebral hemorrhagic infarction, expansion of ventricles of brain caused by cerebral white matter damage. WBD is one of the forms of brain injury in preterm infants the most characteristic, PVL is the final outcome of white matter injury is most serious, the earliest autopsy report of the incidence of PVL in premature infants in the25%-75%. PVL can be divided into focal and diffuse PVL, Focal PVL periventricular deep all cell components of focal necrosis and cyst formation, and closely related to the occurrence of cerebral palsy. Diffuse PVL in oligodendrocyte precursor (Pre-OL) diffuse axonal damage loss, gliosis and star as the characteristic, the consequences of reduced white matter volume and ventricular enlargement, associated with mild exercise of disorder and cognitive, behavioral defects. Because of injury to oligodendrocytes (OL), damage to the myelin formation and allow the signal from one axon spread to neighboring axons, so that children can not adapt to the control of limb position and motion, therefore premature infant brain injury has been considered to be closely related with the occurrence of CP.There are abnormal infants neurobehavioral system brain damage, manifested as motion control ability, ability to respond to environmental stimuli, ability to regulate reduced and reflex abnormalities, and cause the sequelae of nervous system. Bao Xiu-lan20items of neonatal behavioral neurological assessment (NBNA) is a kind of comprehensive behavioral neurological examination method, can conduct a comprehensive evaluation on neonatal behavior ability, various neural reflex and state, early detection of neonatal brain dysfunction, reflect the status and development of premature infant brain development, as well as changes after brain injury, the correct clinical evaluation of premature infant brain development is normal or not very helpful. Peabody developmental motor scale (PDMS) and Bailey (BSID) scale of infant development is a comprehensive assessment of the most effective diagnostic tools of infant development level, can well reflect the movement of children with cerebral palsy and mental development degree.Clinical manifestations of brain injury in preterm infants lack specificity, imaging examination into different types of brain injury diagnosis, evaluating the severity and prognosis estimation is one of the indispensable means. At present on the international IVH the severity of various imaging common evaluation criterion is, according to the Papile classification, Ⅰ stage:single or bilateral subependymal germinal matrix hemorrhage (SEH); Ⅱ:SEH breaking into ventricle, cause IVH:Ⅲ: IVH with ventricular dilatation; IV:IVH with ventricular enlargement, and spread to the surrounding brain white matter infarction. The Ⅰ-Ⅱ class for mild IVH, Ⅲ-Ⅳ for severe IVH. Usually the lateral ventricle longitudinal diameter in6～10mm for slight ventricular enlargement, in11～15mm for moderate enlarged ventricles,>15mm ventricles severe increase. US, MRI has its own characteristics, each have advantages and disadvantages, so how to proper selection and application of complementary, is an important problem faced by clinicians. To comparative study the US and MRI in diagnosis of preterm infants with brain injury,focusing on the evaluation of US in brain injury in preterm infants with advantages and disadvantages, to explore the application value of the US in the diagnosis of brain injury in preterm infants, provide the basis for early diagnosis of optimal mode selection.Reseach Methed1. During the period of January2010to2011December, preterm infants,who gestational age<37weeks in Department of neonatology Nan Fang hospital were included in the study, exclude genetic metabolic disease or congenital deformity of nervous system or other system severely deformed in preterm infants. US was did in one week after birth and before discharge to improve MRI examination, Where the US diagnosis of intracranial lesions, as US in the diagnosis of intracranial lesions group; no intracranial lesions, temporarily as normal control group. If the US is normal, MRI showed intracranial lesions, still belong to the intracranial lesions.2. Collect other clinical data, including the mode of delivery, birth weight, gestational age, Apgar score, birth order, birth gestational age, premature rupture of membranes, intrauterine distress, amniotic fluid, etc.3. Corrected gestational age40weeks later by trained personnel NBNA scores, including the behavior ability (6items, a total of12points); passive muscle tension (4items, a total of8points); active muscular tension (4items, a total of8points); primitive reflex (3items, a total of6points); general valuation (3items, a total of6points). Each score of3division,0points,1points and2points, out of40points,<37divided into anomaly.Tested in newborns between two feeding, the quiet environment, Test at room temperature for22-27℃. Check completed within10min.4. Corrected gestational age of40weeks after the February development scale by Bailey infants (BSID), Peabody developmental motor scale (PDMS) evaluating prognosis, BDIS examination results to the mental development index (MDI) and psychomotor development index (PDI) expression, PDI,MDI<70was abnormal, Peabody score the gross motor developmental quotient (GMQ), fine motor developmental quotient (FMQ), total motor developmental quotient (TMQ) expression, GMQ, FMQ, TMQ<50%is abnormal, monthly follow-up observation of nervous system development. Comparison of two kinds of US, MRI imaging detection rate of brain injury in preterm infants, the follow-up of brain injury in preterm infants, accuracy assessment, US of MRI in the diagnosis of brain injury in preterm infants.Result1.152premature infants with US and cranial MRI examination, US found40cases of intracranial lesions,112cases without exception, the positive rate was26.3%(40/152),27cases of premature infants diagnosed with IVH,11cases of neonatal hypoxic-ischemic encephalopathy (HIE),2cases of PVL. MRI findings of81cases of intracranial lesions with positive,71cases without exception, the positive rate was52.3%(81/152). MRI diagnosis of IPH in8cases, IVH23cases,1cases of subependymal hemorrhage,2cases of ICH,23cases were diagnosed as HIE,6cases of PVL,1cases of hydrocephalus,12cases of IVH+SAH,4cases of IVH+SDH and1cases of IVH+HIE+SAH. There was a significant difference in MRI, US diagnosis of brain injury in preterm infants (χ2=23.078, P<0.001). The accuracy of MRI and US were94.1%,67.1%, sensitivity was90.0%,44.4%. IVH diagnostic accordance rate was85.16%, HIE diagnostic accordance rate was47.83%, PVL consistent diagnostic rate was33.3%. US failed to find SAH, SDH, ICEH.2. All preterm infants returned to test by NBNA, BSID and PDMS, US diagnosis27cases of children with IVH,7cases of NBNA score<35,5cases of GMQ, TMQ<50%,4cases of MDI<70. The>10mm of the lateral ventricle premature infants with low scores, no expansion of ventricles of normal person score, prognosis is good;4cases of children with IPH NBNA score<35,3cases GMQ, TMQ<50%,2cases MDI<70,the prognosis is poor. US diagnosis2cases of children with PVL,2cases of NBNA score<35,2cases GMQ,TMQ<50%, MDI<70, PVL had intelligence, movement evident defects; US diagnosis of11cases of HIE,2cases of NBNA score<35,2cases GMQ<50%,1case TMQ<50%,2cases PDI<70, no obvious clinical symptoms of mild HIE patients, the scores were close to normal, brain damage is heavier, more obvious manifestations of nervous system, clinical degree is high, the prognosis of HIE has a direct relationship with the clinical grading.1cases of hydrocephalus scores were lower; US is not easy to find IVH+SDH, IVH+HIE+SAH, ICEH. Children with low scores may be high probability of sequelas.Conclusion1. US can well display IVH, lateral ventricle enlargement.US has detection rate of the HIE,PVL.US has low detection rate of SAH, SDH, ICEH. MRI focus on the number, range shows more clear, especially to clearly show that SAH, SDH and ICEH, US is not easy to find the lesion.2. There is a significant difference in MRI, US diagnosis of brain injury in preterm infants, US only can be used as first visit and follow-up method.3. Probability following left sequela of the nervous system:①IVH of the lateral ventriculomegaly;②IPH, PVL, hydrocephalus;③has obvious clinical symptoms of severe HIE;④US is not easy to find IVH+SDH, IVH+SAH, IVH+PVL+SAH.