Study On Cerebral Diffusion And Perfusion Function Of Fetal Ventricular Dilation In The Middle And Late Trimester Of Pregnancy By Magnetic Resonance IVIM

Objective:To analyze the changes of the diffusion and perfusion of water molecules in normal fetus and fetal age by means of intralumin incoherent motion(IVIM),and to compare the diffusion and perfusion characteristics of the brain water molecules with ventriculomegaly(VM)fetal brain,The purpose of this study was to explore the changes of the brain water diffusion and perfusion microstructure in VM fetus.Methods:43 cases of slight ventriculomegaly(SVM)were diagnosed by routine fetal(Magnetic resonance imaging)MRI,9 were diagnosed by moderate ventriculomegaly(MVM)fetus;44 cases of fetus without central nervous system development abnormality were included in regular MRI and prenatal diagnosis as normal control(NC).All subjects were scanned with Siemens 1.5T MRI routine sequence and IVIM sequence.The original data was transmitted to Siemens syngo.via frontier researc h platform,and the post-processing software of body diffusion 1.3 was used for post-processing.Two senior doctors who were engaged in pediatric imaging diagnosis were used to measure the parameters quantitatively by double blind method.The frontal white matter(FWM),parietal white matter(PWM),temporal white matter(TWM),occipital white matter(OWM),cerebella hemisphere(CH),and The basal ganglia region(BGR)and pons are the regions of interest(ROI);After ROI drawing,pure diffusion coefficient(D),pseudo diffusion coefficient(D*),perfusion fraction(f)are generated automatically and the corresponding parameters are measured.Variance analysis compared the difference of D,D*,f values between the two groups,and bonfreroni correction was used for the two comparisons.The correlation between D,D*,f and gestational age was analyzed by Spearman.The receiver operating characteristic(ROC)of D,D*,f values was drawn to analyze the sensitivity,specificity and area under the curve(AUC).Results:The difference of D value(F=116.91,P<0.001)of ROI in NC group was statistically significant,but there was no significant difference between D*and f.The highest D value was in the white matter around the ventricles,and FWM is the first.The correlation coefficient of gestational age and BGR(r=-0.528,P<0.001)was the highest.The results showed that the D values of FWM(R~2=0.204,P<0.001),PWM(R~2=0.133,P<0.05),TWM(R~2=0.263,P<0.05),CH(R~2=0.159,P<0.05),BGR(R~2=0.262,P<0.05),pons(R~2=0.384,P<0.001)had correlation with gestational age,and the pons decision coefficient was the highest,followed by BGR.The D values of FWM,PWM and TWM were significantly lower in NC,SVM and MVM groups(P<0.05),and there was no significant difference between the groups(P>0.05).Through ROC curve analysis,the D values of FWM,PWM and TWM can be distinguished between NC group and SVM group,and FWM(AUC=0.89,P<0.05)is the main factor.Conclusion:The detection of the decrease of the pure diffusion coefficient(D)of frontal lobe can be used as an index to evaluate the brain white matter injury in the patients with ventricular distention,which is helpful to mo nitor the progress of fetal brain white matter injury.There are some differences in the pure diffusion coefficient(D)in each brain area of normal fetus,and the value of pure diffusion coefficient(D)can reflect the development and change of normal fetal brain white matter.