| BackgroundCongenital heart disease is not only the most common birth defectin China, but also the leading cause of neonatal mortality, miscarriage, stillbirthand intrauterine death.About 50% of congenital heart diseases can be by surgery or interventional treatment,50% severe malformations are hard to get complicated satisfactory. Congenital heart disease will seriously affect children’s quality of life, give families a heavy mental and financial burden, it’s also a major cause of China’s population of potential life lost. Thus, it is of great importance to make timely detection, diagnosis and then make timely intervention treatment during pregnancy.Prenatal ultrasound or Magnetic resonance imaging (MRI) are mainly taken to diagnose congenital heart disease. MRI examination takes a long time and few people can bare the noise during the inspection, on the other hand, fetal cardiac imaging is affected by intrauterine fetal activity during the inspection, so it’s difficult to get ideal imaging data, thus it’s not easy to make a correct diagnosis. As a result, MRI is not often used in clinical diagnosis. Conversely, prenatal ultrasound is non-invasive, safe and cheap, it is the main method of diagnosing congenital heart disease. However, due to maternal obesity, fetal position, gestational age, fetal movement, amniotic fluid volume, especially the operator’s personal experience and operating practices, the detection rate of fetal congenital heart rate is still to be improved.The diagnosis of congenital heart disease requires the operator familiar with the anatomy and circulation of normal fetal heart, as well as the structural abnormalities and changes in blood flow of congenital heart disease. People learn fetal cardic anatomy from adult anatomical atlas, while fetal cardic anatomy is different from adults’, and only a few ultrasound workers have the opportunity to participate in autopsy study, so ultrasound workers can not have a complete understanding of fetal cardiac structures. Therefore, it is of great significance to construct a digital three-dimensional model of the fetal heart which can be rotated in three-dimensional space and cut in any section.The digital three-dimensional model can provide a vivid image of the fetal cardiac anatomy teaching, and it can help ultrasound workers understand the anatomical abnormalities of fetal congenital heart disease when it combines with the images of prenatal ultrasound, thereby reducing missed prenatal fetal congenital heart disease and improve prenatal ultrasound diagnosis rate of fetal heart abnormalities. Meanwhile, it can lay the foundation for the establishment of various types of congenital heart disease in the three-dimensional anatomical atlas by which medical students can understand the anatomical abnormalities of various types of congenital heart and enhance interest in learning, thus improving the quality of teaching.Many reports about fetal cardiac CT reconstruction depend on the software in CT device which can make the fetal heart three-dimensional visualized, as this method can not get rid of dependence on CT equipment, it’s promotion is limited. Some scholars reconstructed the three-dimensional model of fetal heart, but the method is complicated as it requires milling equipment, the images need to be processed before imported into the reconstruction software, therefore it’s not conducive to conduct extensive research. As a conclusion, there have great significance to seek a simple and fast method to reconstruct the fetal heart.The study is divided into the following three parts.Part one:Reconstruction of digital three-dimensional model of fetal heart[Objective]The objective of this part is to discuss the method and key points of fetal heart perfusion. At the same time, the parameters of CT scanning is also discussed. In the end, the methods of reconstruct three-dimensional model in Mimics software is explored.[Method]1. Sample collectionCollecting 20 abortion fetus which had malformations or are inevitable abortion in Nanfang Hospital from January 2014 to January 2015. The gestational age distributes in 19-34 weeks and the family agreed to donate fetal corpse participate in this study.2. fetal heart perfusion(1) Umbilical venous catheterThe fetal heart is perfused through the umbilical venous. Place the fetus in a square dish, rinse with water, cut the umbilical cord stump to about 10-15cm,then separate the umbilical venous,insert the glass tube and fix them together.(2) Preparation of Perfusion materialsPerfusion formulations:Per 100ml perfusion agent contains self-curing denture acrylic 30g, liquid denture acrylic 70ml, diputy phthalate 30ml, lead oxide 5g and appropriate amount of red oil paint. Prepare perfusion agent 100-150ml according to different gestational age; calculate the amount of each reagent. Put the red oil paint into the liquid denture acrylic, then the self-curing denture acrylic, mix them together at last.(3) Umbilical vein perfusionPerfuse the umbilical venous slowly and stop perfusing when it’s difficult to inject.3.CT scanThe perfused fetus were scanned using dual-source CT (SOMATOM Definition) produced by Germany Siemens company The fetus was placed in the supine position. The average scanning thickness and the layer spacing both are 0.6mm.The scanning results were output by DICOM format and then saved in disk.4. Three-dimensional reconstructionThe DICOM images were input into the Mimics 10.0 lsoftware.edit the mask with the draw,erase and Boolean tools. Finally the digital three-dimensional reconstruction model of fetal heart was reconstructed by using calculate 3D from mask function.[Results]1. It is feasible to perfuse the fetal heart through the umbilical venous.2.The fetal heart digital three-dimensional model was successfully reconstructed with the combination of CT scan and Mimics software. The model revealed the anatomy clearly and it can be arbitrary zoom, pan, rotate at any angle of rotation axis in the three-dimensional space. Meanwhile, each vessel diameter could be measured by the tool in Mimics software.[Conclusions]1.The fetal heart could be well perfused through the umbilical venous if taking care of the speed and the amount of perfusion.2. The quality of the fetal heart perfusion, the distribution of the contrast agent in perfusion agent and the layer spacing and thickness of CT scans could affect fetal the reconstruction of heart digital three-dimensional model.Part two:Analysis of diameters of fetal heart outflow tract in the secondtrimester[Objective]To explore the development of vessels and the diameter measurement distribution.[Method]1. SubjectsThe subjects were those pregnant women who underwent prenatal ultrasound in Nanfang Hospital during November 2014 and March 2015 and met the following conditions:(1)18 to 40 years old, in good health no high blood pressure, diabetes and connective tissue, and no family history of heart disease, congenital heart disease in children with no reproductive history. No pregnant history of exposure to drug use as well as the rays in early pregnant. (2) Gestational age between18 week and 27 week. (3) There were no fetal abnormalities, various indicators of normal fetal development, gestational age consistent with gestational age.2. Data CollectionUse color Doppler ultrasound to scan the fetal heart. Establish the standard sections of fetal cardiac examination, and then find the fetal four chamber view, left and right ventricular outflow tract and three-vessel slice images. Measure the diameters of the ascending aorta, anterior arch artery, posterior arch vascular caliber arteries, the main pulmonary artery and the left and right pulmonary artery.3. Statistical AnalysisSPSS 17.0 statistical software was used for statistical analysis. Compute the mean diameter of each group.[Results]293 pregnant women were selected, and the average of diameters were calculated according to the gestational age.[Conclusions]The development of various organs of the fetus and fetal heart was basically the same, but the development of each period varies.Part three:preliminary study to establish a three-dimensional atlas of congenital heart disease[Objective]To explore the method of reconstructing the fetal heart digital three-dimensional model with congenital heart disease.[Methods]1. Sample collectionCollect the abortion fetus which had congenital heart disease in Nanfang Hospital during January 2014 and January 2015.The family agreed to donate fetal corpse participate in this study.2. Ultrasound images collectionThe fetal heart was scanned again before abortion, collect the images in the apical four-chamber view, outflow tract section left and right outflow tract section, section three vessels, aortic arch long axis and short axis view of the heart and store the images.3. Fetal heart perfusion(1) Umbilical venous catheterThe fetal heart is perfused through the umbilical venous. Place the fetus in a square dish, rinse with water, cut the umbilical cord stump to about 10-15cm,then separate the umbilical venous,insert the glass tube and fix them together.(2) Preparation of perfusion materialsPerfusion formulations:Per 100ml perfusion agent contains self-curing denture acrylic 30g, liquid denture acrylic 70ml, dibuty phthalate 30ml, lead oxide 5g and appropriate amount of red oil paint. Prepare perfusion agent 100-150ml according to different gestational age; calculate the amount of each reagent. Put the red oil paint into the liquid denture acrylic, then the self-curing denture acrylic, mix them together at last.(3) Umbilical vein perfusion Perfuse the umbilical venous slowly and stop perfusing when it’s difficult to inject.4.CT scanThe perfused fetus were scanned using dual-source CT (SOMATOM Definition) produced by Germany Siemens company The fetus was placed in the supine position. The average scanning thickness and the layer spacing both are 0.6mm.The scanning results were output by DICOM format and then saved in disk.5. Three-dimensional reconstructionThe DICOM images were input into the Mimics10.Olsoftware. Edit the mask with the draw,erase and Boolean tools. Finally the digital three-dimensional reconstruction model of fetal heart was reconstructed by using calculate 3D from mask function.[Results]1. Successfully collect the ultrasound images of interruption of aortic arch, tetralogy of Fallot, persistent truncus arteriosus, single ventricle, double outlet right ventricle, hypoplastic left heart with aortic coarctation, hypoplastic left heart with aortic coarctation, hypoplastic left heart with ventricular septal defect and ventricular septal defect.2. Successfully reconstruct the digital three-dimensional model of interruption of aortic arch, tetralogy of Fallot, persistent truncus arteriosus, single ventricle and double outlet right ventricle. The models revealed the anatomy clearly and could be arbitrary zoom, pan, rotate at any angle of rotation axis in the three-dimensional space.[Conclusions]1.Combining CT with Mimics software is a simple, fast, and effective method to reconstruct the digital three-dimensional models of congenital heart disease.2.The digital three-dimensional models of congenital heart disease will be useful in the research, clinical and teaching of fetal heart.3.Construction of congenital heart disease digital three-dimensional atlas provides a vivid three-dimensional graphics for teaching anatomy. If combined with the images of prenatal ultrasound, it will help the ultrasound workers understand the structural malformation and the facets of the ultrasound, thus improve the clinical detection rate of congenital heart disease. |
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