| Part ⅠThe application of conventional Magnetic ResonanceImaging and Diffusion Weighted Imaging in Encephalopathyof PrematurityBackground: In recent years, with the development of perinatal medicine, withimprovement in NICU respiratory care facilities and with management of prematureinfants; the survival rate of premature infants has increased tremendously; especially ofthe very low and the low birth weight infants, whose neuronal developmental outcomeis a matter of concern. Immature neuronal tissue of premature infants is vulnerable andthus can easily get injured. Perinatal hypoxic ischemia, infection/inflammation andother risk factors can lead to activation of number of inflammatory factors,accumulation of excited amino acids and release of oxygen free radical, which canresult in encephalopathy of prematurity (EP). This not only will result indevelopmental disorders of the nervous system which can seriously affect the qualityof life in preterm infants; but also impose a heavy burden on families and society.Objective: To investigate the Magnetic Resonance and DWI performance inencephalopathy of prematurity, to classify of images of the premature brain damage atdifferent gestational age; and to compare their differences.Materials and methods: Cases having one or more of the following conditions wereincluded in the study: premature rupture of membranes, fetal distress, placenta previa,placental abruption, amniotic fluid abnormalities, multiple births, illness duringpregnancy and other dangerous factors in prenatal period; intrapartum or postpartumasphyxia, history of neonatal resuscitation, recurrent apnea, hypoxemia, hypercapnia, chronic lung disease, infection and other risk factors with early clinical manifestations,the clinical manifestations of feeding difficulties, apnea, startle, tics, poor mentalreactions, one minute after birth,5-minute Apgar score less than7points; theexclusion of other encephalopathy, such as inherited metabolic encephalopathy,hypoglycemia, encephalopathy, bilirubin encephalopathy, and congenital braindevelopmental abnormalities. MRI and DWI were done on patients who had one ormore of the above mentioned conditions. Ninety cases with gestational age more than25weeks but less than37weeks were included in the study. Of the ninety cases,52were males and rest were females, with an average gestational age of30.6weeks. Theaverage day of examination was at22.3days post partum. Scanning sequences FSE T1,T2and T2FLAIR and SE/EP DWI were used and analyzed.Results: Conventional MRI and DWI can early display and distinguish betweendifferent types of EP with ischemic and hemorrhagic injury in patients with more than32-weeks of gestational age; and differentiate the types of brain damage in preterminfants below32weeks of gestational age. Diffuse white matter injury was more oftenseen in preterm infants with gestational age of less than32weeks, whereashemorrhagic injury accounted for more cases in infants with more than32weeks ofgestation. Also the formation of periventricular leukomalacia (PVL) was seen more ininfants greater than32weeks of gestation. Forty one cases were proven to be EPbased on features like formation of PVL, accompanying gliosis, delayed myelination,thinning of corpus callosum, widening of the subarachnoid space, enlargement ofventricles and decrease in cerebral volumes.Conclusion: Conventional MRI and DWI can effectively reflect the severity of EPand also can help in estimating prognosis. Part ⅡThe application of Diffusion Tensor Imaging inEncephalopathy of PrematurityObjective. To compare the ADC and FA values in preterm infants with EP and normalfull term infants in order to access the features of preterm brain injury and degree ofdevelopment of nerve fibers.MATERIALS AND METHODS: Twenty infants with EP with corrected gestationalage≥37weeks (with mean corrected gestational age39.7week, and average age of32.5days) were included in the study while twelve normal full-term infants withoutasphyxia (with mean gestational age39.8weeks, and average age10.8days) were usedas control. MRI and DTI scans were performed on both the groups. The region ofinterest (ROI) were selected at the bilateral basal ganglia, thalamus, posterior limb ofinternal capsule, and sensitive and vulnerable areas of frontal, parietal and occipitalcortex. The ADC and FA values were compared and analyzed between infants with EPand normal full term infants.Results: The difference in ADC values of lentiform nucleus, ventrolateral thalamus,posterior limb of internal capsule, frontal, parietal and occipital white matter werestatistically significant (P <0.05) between the two groups. The difference in FA valuesventrolateral thalamus, posterior limb of internal capsule, frontal, parietal and occipitalwhite matter were statistically significant (P <0.05) between the two groups whereasthe difference in FA values of bilateral lentiform nucleus was not significant (P>0.05).Conclusion: DTI sequence can be used to evaluate the EP of preterm infants and topredict the clinical outcome. |
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