MRI Study Of The Development Of The Lumbar Vertebral Ossification Center Of Fetal Specimen In The Second And Third Trimester Pregnancy And Its Comparison With Intrauterine Fetus

Part 1 MRI study of the development of the fetal lumbar vertebral ossification center in vivo in the second and third trimester pregnancyObjectiveTo study the dynamic development of the ossification center of normal fetal L1 vertebral body by magnetic resonance imaging(MRI).Materials and MethodsThis research was a retrospective study.We picked 94 pregnant women(gestation age,GA 23～38 weeks)who accepted fetal spine 1.5T MRI scan in shandong provincial hospital.We measured the morphometric parameters of the ossification center of L1 vertebral body(height、transverse diameter、sagittal diameter and sagittal cross-sectional area)of these normal fetus according to the susceptibility weighted imaging(SWI)sequence,and regression equation was established.ResultsNo sex differences were found.The height and transverse diameter of the ossification center of L1 vertebral body increased logarithmically,according to the following models:y=-1.288+0.535×ln(GA)(R2=0.735)and y=-2.921+1.1 0×ln(GA)(R2=0.795);the sagittal diameter and sagittal cross-sectional area of the ossification center of L1 vertebral body increased linearly,according to the following models:y=-0.295+0.03×GA(R2=0.726)and y=-0.456+0.027×GA(R2=0.709).ConclusionWith no sex differences,the dynamic growth pattern of the ossification center of L1 vertebral body follow logarithmically in height and transverse diameter,linearly in sagittal diameter and sagittal cross-sectional area.The research results provide objective reference parameters for enriching the medical imaging data of fetal spine development and evaluating the developmental status of normal fetal spine.Part 2 MRI study of the development of the lumbar vertebral ossification center of fetal specimen in the second and third trimester pregnancy and its comparison with intrauterine fetusObjectiveTo study the dynamic development of the ossification center of L1 vertebral body of fetal specimens by magnetic resonance imaging(MRI)and compare it with that of intrauterine fetuses as a way to investigate the developmental pattern of normal fetal vertebrae.Materials and MethodsThe 3.0 T MRI scan was performed on 46 fetal specimens(gestation age,GA 17～42weeks)with the sequences of the three dimensional T2-weighted imaging(3D-T2WI).The fetal specimens were derived from sectional imaging anatomy research institute of the medical school of Shandong University.We measured the morphometric parameters of ossification center of L1 vertebral body(height、transverse diameter、sagittal diameter and sagittal cross-sectional area)of these normal fetus,and regression equation was established.ResultsNo sex differences were found.The height and transverse diameter of the ossification center of L1 vertebral body increased logarithmically,according to the following models:y=-1.366+0.549×lnGA(R2=0.944,P<0.05)and y=-2.923+1.134×lnGA(R2=0.941,P<0.05);the sagittal diameter and sagittal cross-sectional area of the ossification center of L1 vertebral body increased linearly,according to the following models:y=-0.163+0.024×GA(R2=0.927,P<0.05)and y=-0.290+0.019×GA(R2=0.960,P<0.05).The growth curve of L1 vertebral ossification center of the fetal specimens with gestational age is similar to that of the intrauterine fetuses.Both the dynamic growths of the ossification center of L1 vertebral body of fetal specimens and intrauterine fetuses follow logarithmically in height and transverse diameter,linearly in sagittal diameter and sagittal cross-sectional area.ConclusionThe growth of L1 vertebral ossification center of fetal specimens has a good correlation with gestational age in the second and third trimester pregnancy,which is is similar to that of the intrauterine fetuses.MRI morphological meter of the relevant vertebral body can be used as a reliable index to assess fetal spinal development,which is important for prenatal assessment and prenatal diagnosis of fetal vertebral abnormalities,and provides a reference for studying the spatio-temporal developmental pattern of the fetal spine.