Comparable Study Of An Intelligent Three-Dimensional Ultrasound System For Imaging The Fetal Cranial Mid-Sagittal View

Object To study the characteristics of intelligent three-dimensional ultrasound imaging system(Smart MSP) to obtain the normal and abnormal fetal brain mid-sagittal plane, which can provide basis on judging the fetal midline structures and laying the foundation for diagnosis of related diseases.Material and Methods(1) Normal Group: The 531 consecutive normal singleton pregnancies from 20 to 28+6 weeks were rapidly visualized of the cranial mid-saggital view by using this new intelligent three-dimensional imaging program. Smart MSP was developed by Mindray DC-8 color doppler ultrasound(China). Doctor “B” did not have any experience in displaying the fetal cranial mid-sagittal view and doctor “A” had the ability to obtain the mid-sagittal plane by three-dimensional ultrasound. The biparietal diameter(BPD) transverse plane and cerebellar diameter plane were used as initial planes to acquire the three-dimensional volumes and then the mid-sagittal planes automatically were extracted by Smart MSP program. Doctor A and B selected the most high quality of mid-sagittal view to store. The other two experts(a and b) independently evaluated the scored three-dimensional mid-sagittal view acquired by doctor A or B. The criteria of scoring the mid-sagitta plane included five structures: corpus callosum, cavum septi pellucidum, tentorium, the fourth ventricle and cerebellar vermis. If the structures can be displayed, scored 1 point; if not, scored 0 point. The total score was 5 points. If the total score is less than 2 points, the case was labelled as failed case.(2) Abnormal cases: To evaluate the clinical value of Smart MSP in diagnosing of cranial midline anomalies, 24 midline anomalies were studied in the same way as normal group, including 5 cases of typica agenesis of corpus callosum, 6 cases of partial agenesis of corpus callosum,1 case of the lipoma in corpus callosum, 5 cases of Dandy-walker malformation, 2 cases of vermian hypoplasia, 4 cases of cerebelar hypoplasia, 1 case of rhombencephalosynapsis, 2 cases of Blake’s porch cyst, 1 case of congenital pachygyria, 3 cases of arachnoid cyst, 1 case of schizencephaly, 1 case of pfeiffer syndrome.Results(1) Normal group: The “A” experienced doctor only successfully visualized the cranial mid-sagittal view in 38 normal cases(7.16%) with two-dimensional ultrasound, while non-experienced doctor could not image any mid-sagittal plane with two-dimensional ultrasound. The cranial mid-sagittal view was successfully visualized in 449 normal cases(84.6%) that were acquired from BPD initial plane by Smart MSP program by experienced and non-experienced doctor. The mid-sagittal view was successfully demonstrated in 486 normal cases(91.5%) which initial plane was cerebellar diameter plane.When the initial plane was BPD plane, the scores of reconstructed mid-sagittal plane between “A”doctor and “B” doctor use Smart MSP was statistically significant(F=4.74, P=0.01). When the initial plane was transcerebellar plane, the scores of reconstructed mid-sagittal plane between A doctor and B doctor use Smart MSP was also statistically significant(F=3.22, P=0.04). The time which was needed to obtain the mid-sagittal plane by different doctors was statistically significant(F=10.20, P <0.05).(2) Patient group: 24 cases of abnormalities were diagnosed by Smart MSP, including 5 cases of typica agenesis of corpus callosum, 6 cases of partial agenesis of corpus callosum,1 case of the lipoma in corpus callosum, 5 cases of Dandy-walker malformation, 2 cases of vermian hypoplasia, 4 cases of cerebelar hypoplasia, 1 case of rhombencephalosynapsis, 2 cases of Blake’s porch cyst, 1 case of congenital pachygyria, 11 cases of hydrocephalus, 3 cases of arachnoid cyst, 1 case of schizencephaly, 1 case of pfeiffer syndrome. Among them, six cases were confirmed by autopsy, nine cases confirmed by prenatal MRI, one case confirmed by postnatal CT scan and five casese confirmed by telephone.Four cases refused autopsy and four cases were lost to follow up.Conclusions(1)Smart MSP can improve the visualization rate of mid-sagittal plane in second-trimester and reduce the difficulty of the operation, especially for less-experienced doctor. The midline structures of the fetal brain can be successfully visualized by Smart MSP, which were particularly difficult to obtain by two-dimensional ultrasound.(2) The cerebellar diameter plane as the initial section could reconstruct a more high quality of three-dimensional median views by Smart MSP. The two factors which included abdominal thickness and the location of placenta would affect the image quality. These factors including fetal position and maternal body mass index in a certain range could not influence the quality of image in mid-trimester pregnancy (3) Smart MSP is a feasible and easy method to visualize the median plane of fetal brain, which may be used to screen the fetal midline anomalies.