Magnetic Resonance Imaging(MRI) Evaluation Of Normal Fetal Cerebral Cortex Development

Objectives:By MRI measurement of normal living fetus cerebral cortex and the adjacent structure of the diameter of each line,calculate of different gestational age fetal cortical cortex(FCC)development ranges of medical reference values and correlation with gestational age(GA),the conclusions were analyzed and evaluated for the FCC development and disease diagnosis at different GA.Methods:A total of 326 cases of normal fetal head with 1.5T MRI imaging at 24-39 weeks of gestation from January 2016 to October 2017 were collected.All of them were single fetus and had no complications during pregnancy.Select the standard section on the T2 WI sequence,Measure separately sylvian?parietoccipital?cingulate ?convexity fissures depth and cortical thickness here,and adjacent to the lateral triangle of the lateral diameter,repeat 3 times,find the average,and statistical analysis.Calculate the reference value range of cortical structure index of each GA group and its correlation with GA.Results:The sylvian?parietoccipital?cingulate ?convexity fissures depth increase with GA,the reference range is respectively 14.30~14.58 mm,6.14~6.56 mm,4.99~9.30 mm,8.49~8.91.Respectively 27-31 weeks,27-30 weeks,28-30 and 35-37 weeks,28-32 weeks increased significantly.The sylvian ? parietoccipital ? cingulate ?convexity fissures depth and GA(in weeks)was positive correlation(r=0.573,0.418,0.624,0.493,P< 0.05);The sylvian?parietoccipital?cingulate ?convexity fissures cortical thickness decrease with GA,the reference range is respectively 1.59~1.62 mm,1.57~1.61 mm,1.58~1.62 mm,1.54~1.72 mm.Respectively 27-31 weeks,31-35 weeks,32-36 weeks,32-36 weeks decreased significantly.The sylvian?parietoccipital?cingulate ?convexity fissures cortical thickness and GA(in weeks)was negative correlation(r=-0.175,-0.232,-0.202,-0.309,P< 0.05);The lateral triangle of the lateral diameter and GA had no significant correlation(P>0.05),the reference range is 5.45~8.73 mm.Conclusions:MRI has become an important tool for prenatal diagnosis,FCC structure was evaluated by 1.5T MRI,can accurately show the development of cerebral cortex,the standard of MRI evaluation for normal FCC was obtained,it provides important reference for perinatal evaluation of cerebral cortical development state.