| BackgroundHypoxic-ischemic encephalopathy?HIE?was due to asphyxia and other causes of brain tissue damage,which hinders the myelination process of white matter fibers,destroys the integrity of fiber bundles,it had high morbidity and mortality postnatal.Ultrasound was the conventional first choice imaging technique for prenatal examination of the fetus,but it didn't show the microstructural and functional information of fetal brain development.Diffusion tensor imaging?DTI?could better display functional information of myelin sheaths,it was the only non-invasive examination technology that could clearly display the structure of white matter at present.It had been preliminarily used in adult brain examination,but there was still a lack of DTI data on fetus,especially at different gestational ages.ObjectiveUsing the DTI technology,it was observed the normal fetal different side,different gender,different structure,different gestational age,the brain structure of the fractional anisotropy?FA?values and apparent diffusion coefficicent?ADC?values,different gestational age,the severity HIE of brain injury structure FA value and ADC values and the treatment after the birth of the FA value,ADC value and neonatal behavioral neurological assessment?NBNA?score and prognosis of severe HIE assessment.For the early diagnosis and prognosis of fetal HIE and provide objective basis for imaging diagnosis and timely termination of pregnancy.MethodsFrom June 2015 to July 2016,150 cases of normal pregnant women examined by fetal DTI scan were selected.The gestational age was 24-40 weeks.75 fetuses were male and female respectively.The fetus was divided into less than 27 weeks group,28-35 weeks group and more than 36 weeks group according to the myelination process of white matter,and 50 cases in each group.50 cases of normal newborns and1 year old infants was selected.HIE also collected 270 cases of fetal head DTI scan and hospitalization,delivery,gestational age was 24-40 weeks,according to the classification standard of HIE brain damage as mild,moderate and severe group,90cases in each group,it was divided according to gestational age in normal control group were divided into 3 groups,30 cases in each group.90 cases fetal severe HIE were followed up by DTI scan at 1 years after birth.Using GE 1.5 T MR,the inspector's DTI image data was introduced into GE workstation,and the region of interes?ROI?of brain structure was divided on DTI image.Data processing was done by ADW 4.6 software system to get ROI FA value and ADC value.The NBNA was used to score after fetal HIE birth and 1 year follow-up.Statistical analysis was carried out using SPSS 19 statistical software,and P<0.05 was statistically significant.Results1.Fetal brain structure of gray,shallow white matter and deep white matter average of FA values and ADC values were?0.080±0.005?,?0.153±0.016?,?0.339±0.034?and?1.632±0.117?×10-3mm2/s,?2.544±0.207?×10-3mm2/s,?1.598±0.137?×10-3mm2/s respectively,there was significant difference between fetal brain structure?P<0.05?,the FA value from big to small in turn was white matter,deep white matter and shallow gray matter,ADC value from big to small in turn was deep white matter,gray matter and shallow white matter.2.There were significant differences in FA values and ADC values in the brain structure of gray matter,shallow white matter and deep white matter in the fetus less than 27 weeks,28-35 weeks and more than 36 weeks?P<0.05?.With the increase of gestational age,the FA value of the brain structure increased,and the FA value was positively correlated with the gestational age,and the ADC value decreased and was negatively correlated with the gestational age.3.Fetal HIE in less than 27 weeks,28-35 weeks,more than 36 weeks of brain structure of the FA values and ADC values were?0.140±0.011?,?0.167±0.018?,?0.186±0.013?and?3.216±0.242?×10-3mm2/s,?2.631±0.132?×10-3mm2/s,?2.214±0.177?×10-3mm2/s respectively,FA values increased with gestational age gradually increased,ADC values decreased gradually.4.The mild,moderate and severe fetal brain HIE of the FA values and ADC values were?0.187±0.013?,?0.163±0.015?,?0.141±0.010?and?2.098±0.233?×10-3mm2/s,?2.659±0.310?×10-3mm2/s,?3.293±0.356?×10-3mm2/s respectively,brain structure of FA values decreased with the severity of disease,the ADC values increased gradually.5.Mild fetal HIE that before treatment and after birth the structure of the FA values and ADC values had significant difference?P<0.05?,after birth and normal neonates had no significant difference?P>0.05?.Moderate HIE that before treatment and after birth and neonatal brain structure of the FA values and ADC values had significant difference?P<0.05?.Severe HIE that before treatment and after birth the structure of the FA values and ADC values showed no significant difference?P>0.05?,the differences were significant and normal neonates after birth?P<0.05?.6.The NBNA score of fetal mild,moderate and severe HIE that after treatment was?37.10±2.52?,?32.92±2.36?,?23.80±2.59?respectively,the NBNA score decreased with the decrease of FA value of brain structure,which was positively correlated,and negatively correlated with the increase of ADC value.7.Fetal severe HIE rehabilitation treatment for 1 year follow-up and normal infants brain structure of the FA values and ADC values were?0.151±0.014?,?0.428±0.036?and?3.282±0.130?×10-3mm2/s,?0.863±0.075?×10-3mm2/s respectively,it was significant difference?P<0.05?,and after birth the structure of treated FA values and ADC values had no significant difference?P>0.05?.Conclusion1.The FA value and ADC value of fetal brain structure were closely related to the location and number of white matter fiber bundles.The FA value of fetal brain structure increases with the increase of fetal age,and the ADC value decreases with the increase of fetal age.DTI could quantitatively analyze the development of white matter in fetal brain at different gestational ages.DTI was provided an early objective diagnostic basis for the diagnosis and dynamic observation of fetal brain structure.2.The FA value of fetal HIE increases with the increase of gestational age,and decreases with the aggravation of the lesion.The ADC value decreased with the increase of gestational age and increased with the severity of the lesion.The FA value and ADC value could be used for early quantitative evaluation of HIE white matter damage and prognosis,providing diagnostic criteria for timely termination of pregnancy. |
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