Application Of Transabdominal Three-dimensional Ultrasonography On Detection The Development Of Fetal Cerebellar Vermis

ObjectiveTo explore the application value of transabdominal three-dimensionalultrasonography Ominiview combining with VCI in diagnosis of fetal cerebellardiseases, observe and measure the CM width, the size of cerebellar vermis, the positionof vermis and tentorium changing with the gestational week, and explore the differentialdiagnosis of cerebellar vermis dysplastic diseases from two aspects of morphologicaland biological measurements.MethodsA total of130normally developed fetuses were examined by fetal brain3DUSfrom October2012to October2013in Chinese PLA General Hospital. Over the sameperiod, including13cases of suspected DWS,36cases of MCM detected by2DUS. TheCM width was measured on the standard transverse section; The morphology andanatomy of fetal cerebellar vermis development were observed on the median sagittalsection, and the fetal cerebellar vermis antero-posterior length, cranio-caudal length,perimeter, surface area, BV angle, BT angle were measured. And put forward thequantitative classification methods of fetal DWS according to vermian morphologicaland biological measurements.Results(1) In healthy fetuses, cisterna magna width was associated with gestational age, with thetrend of first increased and then reduced with the change of gestational age,andreached its peak at around32-33gestational age.The regression equation was CMwidth (cm)=-1.50×10-5GA3+0.05GA-0.303, R2=0.336; prognosis was goodwhen MCM appeared only around32gestational age. (2) In healthy fetuses, the vermis antero-posterior length, cranio-caudal length,perimeter, surface area all increased with gestational age increasing. The regressionequations were: antero-posterior length (cm)=-0.001GA2+0.10GA-0.933, R2=0.907; cranio-caudal length (cm)=-0.002GA2+0.191GA-1.928, R2=0.955;perimeter (cm)=-0.01GA2+0.836GA-9.169, R2=0.950; surface area (cm2)=-0.002GA2+0.313GA-4.748, R2=0.968(GA represents gestational age). Thesurface area had the best relevance and repeatability.(3) BV angle and BT angle did not increase with the gestational age, they were8.0°±3.2°and31.4°±7.5°, respectively. Vermian rotation was defined as the BV anglemore than14.4°, and the elevated tentorium as the BT angle greater than46.6°.(4) Evaluated from cerebellar morphological and biological measurements,suspectedDWS were diagnosed as DWM2cases, DWV3cases, isolated vermian rotation4cases and MCM4cases finally. In DWM, cerebellar vermis lost their normal “heart”shapes, the main anatomical marks were not clear, the vermis sizes were lower thanthe fifth percentile site of normal fetuses, with MCM and BV angles and BT anglesboth increased significantly. In DWV, cerebellar vermis lost their normal “heart”shapes, the main anatomical marks were not clear sometimes, the vermis sizes werelower than the fifth percentile site of normal fetuses, with or without MCM, BVangles increased and BT angles were within the normal range. In groups of isolatedvermian rotation and MCM, cerebellar vermis showed normal shapes and sizes, BTangles were within the normal range, BV angles slightly increased with the former,while the latter showed MCM with or without sligtly increased BV angles.Conclusions(1) The fetal brain median sagittal plane can accurately be obtained with the technologyof transabdominal three-dimensional ultrasonography Ominiview combining withVCI, on this section the morphological structures, sizes and position of cerebellarvermis can be evaluated. (2) On the median sagittal plane, we can make the differential diagnosis of DWM, DWV,isolated vermian rotation and MCM based on the features of vermian morphologicaland biological measurements.