Preliminary Investigations On The Value Of Three-dimensional Ultrasound Reconstruction Of Fatal Lip And Palate As Well As Tomographic Ultrasound Imaging For The Diagnosis Of Fetal Cleft Lip And Palate

Background & objectiveFetal cleft lip and palate is the most common congential facial anomaly. The incidence of cleft lip and palate in the newborns is 1.8∶1000 in China. In recent years, along with the improvement of the equipment performance and the increase of ultrasonic inspector's recognition toward the cleft lip and palate, the prenatal diagnosis level of cleft lip has greatly increased. But because of the influence of palate scan angle and sheltering of ambient structure to the two-dimensional ultrasonic observation, it is commonly accepted that cleft palate is the difficulty of prenatal diagnosis. It is shown in the researches that the type of cleft lip & palate is apparently related to whether structural malformation and chromosome abnormality are attached and the pathologic change type determines the effect of plastic surgery and the life quality of the sick baby. Therefore, proper prenatal diagnosis of cleft lip and palate & determination of its type has an important significance to the evaluation of the forecast on the fetus and instruction to the selection of clinical pregnant results.Three-dimensional ultrasound technology expands the spacial imaging function of the ultrasound technology and provides richer diagnosis information on the basis of two-dimensional image and make the level of ultrasonic diagnosis raise from plane to solid multiple aspects, therefore it assists in the diagnosis of malformation of fetus. At the beginning of nineties of last century, foreign countries had already applied this technology into the clinic, but it started later in our country. It is now commonly accepted that three-dimensional ultrasound can show the fetal lip better than two-dimensional ultrasound and that it remedies the defect of two-dimensional ultrasound in the difficulty regarding detailed description of malformation characteristics and judgment of pathological change extent. But because the palate position is hidden, the cleft palate is small organ malformation, in the meantime due to the limitation of three-dimensional technology itself, it it necessary to go further in the research of diagnosis regarding cleft palate.Tomographic ultrasound imaging (TUI) is the three-dimensional ultrasound imaging model researched & developed recently. It can carry out multiaspect tomography to the three-dimensional ultrasonic volume data, obtain the tomography image of volume data in various directions and observe the fatal structure in a new visual angle. In theory, this item of technology should be able to obtain the tomographic image of lip and palate in various directions and assist in the inspection of fatal cleft lip and palate.This research plans to carry out the following works using three-dimensional ultrasound technology:1. Observation and comparation regarding selection of three-dimensional ultrasound sampling section on fatal lip and palate region and imaging characteristics.2. Exploration of the indication status of TUI for the normal structure of fatal facial region3. Preliminary investigations on three-dimensional ultrasonic reconstruction method for palate region.4. Exploration of the diagnosis value of TUI for the fatal cleft lip and palate.Equipment and methods EquipmentGE Voluson 730 Expert model Color Doppler Ultrasound Diagnostic Apparatus equipped with RAB2-5L volume probe in frequency of 2-5MHz.Methods1. Put 6 specimens of aborted fetus (gestational weeks: 17-28, average: 23 weeks) of normal facial region into the water and gather the three-dimensional ultrasonic volume data on median sagittal section, diagonal sagittal section, median sagittal section through mandible, transverse section through alveolar process and section through biparietal diameter of the facial area in the fetal specimens. Select the saggital section of the palate as the reference plane, use the transverse section of the palate to carry out the three-dimensional reconstruction and observe from the mouth floor to the vertex of the fetus.2. Use the median sagittal section through mandible to gather 22 specimens of three-dimensional ultrasonic volume data in the intrauterine fetus (gestational weeks: 20-34, average: 24 weeks, ages of pregnant women: 25-35, average age: 30). Apply TUI technology to carry out tomography to the sagittal section, transverse section and coronal section of the 22 specimens of volume data.3. Use the median sagittal section through facial region & transverse section through alveolar process to gather 23 specimens of three-dimensional ultrasonic volume data in the intrauterine fetus (gestational weeks: 19-35, average: 26 weeks, ages of pregnant women: 23-36, average age: 30) to carry out the three-dimensional ultrasonic reconstruction of palate. Carry out three-dimensional ultrasonic reconstruction of palate for the three-dimensional ultrasonic volume data of facial region in item 2 gathered on the median sagittal section through mandible of 22 specimens of intrauterine fetus. The reconstruction uses compound model (surface texture model 90%. surface smooth model 10%), other reconstruction methods follow method 1. 4. Use the median sagittal section through facial region & transverse section through alveolar process to gather 7 specimens of three-dimensional ultrasonic volume data in the fetus that are inspected as cleft lip and palate fetus in our hospital (gestational weeks: 21-31, average: 26 weeks, ages of pregnant women: 21-46, average age: 30) in two-dimensional ultrasound inspection use TUI technology to carry out ultrasonic tomography to the volume data on the sagittal section, transverse section and coronal section and observe the obtained image.Results1. Research on specimens of aborted fetus shows that the lip, alveolar process and inner tooth germs can be clearly reconstructed on the median sagittal section, diagonal sagittal section(less than30°) and transverse section through alveolar process, but the reconstruction of the secondary palate is unsatisfactory. The fetal lip, alveolar process, inner tooth germs and secondary palate can be reconstructed on median sagittal section through mandible and the image is clear. Section through biparietal diameter is improper to be used as gathering section of palate volume data.2. The intrauterine fetal volume data gathered from median sagittal section, transverse section through alveolar process and median sagittal section through mandible can clearly reconstruct the alveolar process and tooth germs. Volume data gathered from median sagittal section and transverse section through alveolar process can not reconstruct the secondary palate, but the three-dimensional data gathered from median sagittal section through mandible can clearly reconstruct the secondary palate. The volume data gathered from all the above three methods can not reconstruct the soft palate.3. After TUI treatment to the volume data of intrauterine fetus gathered from median sagittal section through mandible, we can obtain the tomography image of lip and hard palate on sagittal section, transverse section and coronal section. The soft palate can be shown on the sagittal section and its boundary is unclear on the transverse section and coronal section and its imaging is unsatisfactory.4. All the 7 specimens of cleft lip and palate have obtained satisfactory TUI image. The fetal cleft lip and palate shown in the image conforms to the actual malformation of the fetus after birth.Conclusions:1. Median sagittal section, diagonal sagittal section(less than30°) and transverse section through alveolar process can all be used as the gathering section for three-dimensional ultrasonic volume data of lip and alveolar process. Median sagittal section through mandible can all be used as the gathering section for three-dimensional ultrasonic volume data of lip and hard palate.2. Among all the sections applied in this research, only the volume data gathered from median sagittal section through mandible can obtain the three-dimensional image of the hard palate. In the TUI image, the tomography of hard palate on sagittal section, transverse section and coronal section is shown and the continuity of the hard palate can be evaluated.3. TUI image can indeed observe cleft lip and palate. Although three-dimensional ultrasound temporarily can not replace two-dimensional ultrasound, but it can serve as the beneficial supplement of the two-dimensional ultrasound and it can assist in the increase of the prenatal diagnosis level of cleft lip and palate.