Search

An azygos lobe is a rare anatomic variant of the lung which may be misdiagnosed as other pathological conditions. There is a dearth of information on the clinical characteristics of children with azygos lobe. This study aims to summarize the clinical features of children with azygos lobe, which may be helpful to improve recognition and clinical care of those patients. Clinical findings of the children with imaging findings of azygos lobe were collected and analyzed. In this study, 50 children with azygos lobe were included. A total of 28% cases were found to have azygos lobe incidentally. The remaining 72% cases were diagnosed when they presented with respiratory symptoms including cough (36%), fever (34%), wheezing (18%), dyspnea (14%), and cyanosis (8%). Congenital heart disease, Down syndrome, and other respiratory malformations were also found in a small proportion of these patients. Only 7 (14%) patients suffered from azygos lobe infection and were clinically cured after reasonable anti-infective treatment. Compared with the non-infected group, no valuable risk factors were found to be related to azygos lobe infection. All children who had azygos lobe infections responded to appropriate antibiotics therapy. There was no evidence that an azygos lobe was associated with recurrent infections. Conclusion: The clinical characteristics of children with azygos lobe are nonspecific and diagnosis relies on chest imaging. Some congenital abnormalities may be complicated with azygos lobe. It is reasonable to keep watch over those patients without symptoms. What is Known: • An azygos lobe is a congenital variation of the lung. • Azygos lobe can mimic various pathological conditions leading to misdiagnosis and inappropriate treatment in adults, which presents challenges during thoracic surgical interventions. What is New: • Azygos lobe in children may be complicated with other congenital abnormalities. • There is no evidence that azygos lobe is associated with recurrent infections. • After appropriate anti-infective treatment, those children with azygos lobe infections could be clinically cured. [ABSTRACT FROM AUTHOR]

In this work, ReaxFF molecular dynamics (MD) simulation was adopted to investigate the effect of superheated steam on the conversion of the kaolinite-associated Barkol kerogen (BLK) and reveal the corresponding mechanism. The ReaxFF simulated weight loss rate (DTG) and release tendency of H 2 O, H 2 and CO 2 for BLK and the kaolinite-associated BLK agreed well with the results of Py-MS experiments. H-rich rate, double bond equivalents (DBEs), and hydrocarbon content were adopted to assess the quality of C 5 -C 40 , and configurations of C 40+ were extracted to investigate the characteristics of residues. And the H 2 O steam - and kaolinite-involved (steam refers to the superheated steam) reactions were analyzed. The results indicate that B- and L-acid sites of kaolinite co-catalyzed decomposition of BLK into heavy oil and shale gas in the kaolinite-pyrolysis system, and in steam/kaolinite-pyrolysis system, H 2 O steam further promoted decomposition of BLK into higher quality shale oil, especially for C 5 -C 13 components, remaining higher aromatic and porous residues. And this enhanced effect of H 2 O steam is attributed to kaolinite and the induced decomposition of H 2 O steam molecules and their participation as reactants in reactions in two aspects: i) interaction between kaolinite and H 2 O steam , on one hand, inhibited formation of L-acids and facilitated generation of B-acids to catalyze carbocation ion reactions process, further weakened dehydrogenation of organics catalyzed by L-acid sites, and enhanced cracking of residues catalyzed by B-acaid sites, on the other hand, promoted decomposition of H 2 O steam molecules to form H-rich environment and further weakened dehydrogenation of organics; ii) attacking C ar directly, H 2 O steam promoted shedding of alkyl side chains and ring-opening of aromatics to increase the –CH 2 – content in shale oil. This paper provides theoretical guidance for further understanding mechanism of H 2 O steam on pyrolysis of kaolinite-associated kerogen and corresponding catalyst development and preparation. [Display omitted] • The enhanced effect of H 2 O steam on pyrolysis of kaolinite-associated BLK was studied. • Rationality of ReaxFF simulation was guaranteed by Py-MS and FT-IR results. • Kaolinite catalyzed BLK pyrolysis into C 14 -C 40 with low quality of C 5 -C 13. • Quality of C 5 -C 40 and properties of C 40+ were enhanced with H 2 O steam injection. • Steam enhanced BLK pyrolysis by affecting bonds breakage directly and acid sites formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Residues were obtained by python codes to investigate aromaticity and porosity. • Numbers of the broken C O, C N and C S bonds of pyrolysis systems were given. • The H 2 O SS involved products and typical pathways of residues were presented. • The H 2 O SS enhanced decomposition of residues during the initial BLK pyrolysis. • BLK induced decomposition of H 2 O SS which participated in pyrolysis reactions. In this work, ReaxFF molecular dynamics (MD) simulation was applied to elucidate the enhancement effect of superheated steam on the conversion of residues into shale oil and gas during the initial pyrolysis of Barkol kerogen (BLK), and the corresponding mechanism was revealed. The weight loss rate (DTG) of BLK pyrolysis obtained from ReaxFF MD simulation agreed well with that form thermogravimetric experiment. Reaction pathways of the H 2 O SS molecules (SS refers the superheated steam) and partial C 40+ obtained from the extracted residues were analyzed. The results indicate that H 2 O SS facilitated the conversion of residues to oil and gas in aspects of yield, heteroatomic removal rate, number of broken bonds of C C, C N, C S, distribution of carbon number of C 40+ , aromaticity and porosity. And this enhancement effect of H 2 O SS is attributed to decomposition of H 2 O SS molecules with inducement of kerogen and participation of H 2 O SS as reactants in reactions during the initial pyrolysis of BLK. Analysis of typical reaction pathways shows that H 2 O SS molecules were involved in disintegration of C C, C N, and C S bonds, shedding of aromatic substituents, ring-opening of aromatic heterocycles, removing aromatic heteroatoms, and further conversion of aromatics into aliphatics. These chemical reactions increase the porosity and pore connectivity of residues. Simultaneously, H 2 O SS expansion promoted the deformation of the kerogen carbon skeleton, resulting in initial increase of porosity of kerogen. In addition, the mechanism of further conversion of aromatics to aliphatics for steam-pyrolytic residues was given. This paper provides theoretical guidance for in-situ conversion process (ICP) of kerogen with the superheated steam injection in the further understanding mechanism of H 2 O SS on initial pyrolysis of kerogen and corresponding catalyst development and preparation. [ABSTRACT FROM AUTHOR]

• Pyrolysis of kerogen in superheated steam was studied using ReaxFF MD simulation. • The saturation of gas and light shale oil was evaluated by double bond equivalents. • The path of O water and H water were analyzed. • The saturation of pyrolytic products was improved at superheated steam atmosphere. • The H 2 O involved in formation reactions of R-OH, Ar-OH, H 2 , NH 3 and H 2 S. In this work, the effect of superheated steam on pyrolysates for in-situ pyrolysis of kerogen was investigated through ReaxFF molecular dynamics simulation in terms of the saturation of pyrolytic shale gas and light shale oil. The double bond equivalents were adopted to characterize the saturation of gas, light shale oil and the hydrocarbon. The existence form of H 2 O molecules, introduced by superheated steam (named the environmental H 2 O molecule, H 2 O water), were obtained using python scripts to analyze bond order file. And the reaction pathways of several representative pyrolysates (propanol, methanol, phenols and H 2), generated by the participation of H 2 O water molecules, were analyzed. The results indicated that, compared with pyrolysis at nitrogen atmosphere, saturation of shale gas and light shale oil were both promoted at superheated steam atmosphere, especially for the light shale oil. Under superheated steam circumstance, the inhibited dehydrogenation of kerogen is the primary reason for the saturation improvement of products. The secondary cause is the bonding of H water and OH water radicals to carbon-containing radicals, which may have a hampering effect on the radical recombination reaction of short chains. During pyrolysis of kerogen with superheated steam injection, H 2 O water molecules could be involved in a serious of chemical reactions: the decomposition of char and heavy shale oil, opening reaction of heterocyclic rings, transmission and exchange of OH radicals and the formation of products (hydrocarbon, alcohols, NH 3 , H 2 S, H 2 , etc.), principally via attacking radicals or fragments. The typical reactions in which H 2 O water molecules involved were given. This study would provide theoretical support for in-situ pyrolysis technology of oil shale with superheated steam injection. [ABSTRACT FROM AUTHOR]

• FT-IR was applied to obtain quantitative information of functional groups and substituted positions of aromatic rings of Fushun kerogen. • The number of condensed rings of aromatic structure and alicyclic were taken into account in molecular construction. • A new calculation method for the average chain length and branching degree was proposed. Solid state 13C nuclear magnetic resonance (13C NMR), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) were carried out to characterize the chemical structure characteristics and to establish the average molecular structure of kerogen extracted from Fushun oil shale. NMR predictor was used to calculate the chemical shift of carbon atoms to verify the rationality of the constructed model. And the stability of 3D model was studied by molecular dynamics (MD) simulations. 13C NMR results demonstrate that Fushun kerogen consists of 76.98% of aliphatic structure dominated by long linear methylene and 21.6% of aromatic structure (mainly protonated aromatic carbon). Functional groups observed in 13C NMR spectra were also detected in FT-IR spectra at wavenumber range of 1800-1000 cm−1. XPS analysis indicates that nitrogen-containing groups were pyrrole, pyridine and primary amines, and sulfur existed as sulfoxides, thiophenes and mercaptans. By comparing the calculated 13C NMR and experimental 13C NMR, it was found that the aromatic structure condensed in two aromatic rings and the aliphatic structure without alicyclic and epoxy ether were more rational for the chemical structure model of Fushun kerogen. A new method to evaluate the average methylene chain length was proposed. Finally, a relatively rational 2D molecular structure with a molecular formula of C 228 H 350 O 10 N 6 S 3 was constructed. The most stable 3D periodic structure (20 optimized molecules, 48.44 × 49.63 × 50.28 Å3) with the lowest total potential energy was obtained by MD simulation and density of it was 0.943 g/cm3. [ABSTRACT FROM AUTHOR]

Objectives: Existing brain extraction models should be further optimized to provide more information for oncological analysis. We aimed to develop an nnU-Net–based deep learning model for automated brain extraction on contrast-enhanced T1-weighted (T1CE) images in presence of brain tumors. Methods: This is a multi-center, retrospective study involving 920 patients. A total of 720 cases with four types of intracranial tumors from private institutions were collected and set as the training group and the internal test group. Mann–Whitney U test (U test) was used to investigate if the model performance was associated with pathological types and tumor characteristics. Then, the generalization of model was independently tested on public datasets consisting of 100 glioma and 100 vestibular schwannoma cases. Results: In the internal test, the model achieved promising performance with median Dice similarity coefficient (DSC) of 0.989 (interquartile range (IQR), 0.988–0.991), and Hausdorff distance (HD) of 6.403 mm (IQR, 5.099–8.426 mm). U test suggested a slightly descending performance in meningioma and vestibular schwannoma group. The results of U test also suggested that there was a significant difference in peritumoral edema group, with median DSC of 0.990 (IQR, 0.989–0.991, p = 0.002), and median HD of 5.916 mm (IQR, 5.000–8.000 mm, p = 0.049). In the external test, our model also showed to be robust performance, with median DSC of 0.991 (IQR, 0.983–0.998) and HD of 8.972 mm (IQR, 6.164–13.710 mm). Conclusions: For automated processing of MRI neuroimaging data presence of brain tumors, the proposed model can perform brain extraction including important superficial structures for oncological analysis. Clinical relevance statement: The proposed model serves as a radiological tool for image preprocessing in tumor cases, focusing on superficial brain structures, which could streamline the workflow and enhance the efficiency of subsequent radiological assessments. Key Points: • The nnU-Net–based model is capable of segmenting significant superficial structures in brain extraction. • The proposed model showed feasible performance, regardless of pathological types or tumor characteristics. • The model showed generalization in the public datasets. [ABSTRACT FROM AUTHOR]

Introduction: Lymphatic malformation (LM), most commonly present in the neck area, is benign vascular malformations of the lymphatic system. In an infant, however, LM poses a high risk of adverse outcomes.Case Presentation: We present a case with a giant fetal LM. Through ultrasonography, at 23+ weeks of gestation, a septate cystic mass 7.2× 6.5× 6.3 cm in size was found on the right side of the fetus's neck. After extensive counseling by the multidisciplinary team, the parents chose to continue the pregnancy. Severe fetal tracheal compression was observed at 29 weeks by magnetic resonance imaging (MRI). At 31 weeks and 5 days, owing to suspected fetal distress, an emergency cesarean section was performed and a male baby weighing 1720 g was delivered. The mass was 10× 16× 8 cm in size and ex utero intrapartum treatment (EXIT) was implemented. Due to progressive growth of the mass secondary to intralesional bleeding, an intralesional injection of bleomycin was administered three days later. This injection was repeated at the age of 1 month and 8 days. The baby was followed up and, by a year after his birth, LM had disappeared. The baby has since been in good health.Conclusion: Accurate prenatal diagnosis and regular monitoring of a fetus with LM may improve prognosis. It is essential to have a trained multidisciplinary team to evaluate the condition of the fetus and the neonate and to provide treatment based on the evaluation. Our experience with intralesional bleomycin injection for the treatment of a giant fetal neck LM in a preterm infant had a favorable outcome. Long-term follow-up by a multidisciplinary team is needed in such cases. [ABSTRACT FROM AUTHOR]

An interlayer existed between the ballast layer and subgrade in the conventional railway substructure. Considering that the shear strength τ of the interlayer soil was influenced by the changes in the ballast grain content and water content, this aspect was explored in the present study. Monotonic triaxial tests were fulfilled, which considered five coarse grain contents fv and three water contents of fine soil wf. The results showed that the growth in fv contributed to an increment in τ of the soil mixture under both saturation and unsaturation. Conversely, in previous studies, the growth of fv induced an increment in τ under saturation, but a decline in that under unsaturation. This was explained by the competing influences of fv and suction ψ: in previous studies, increasing fv induced a decline in the dry density of the fine soil fraction ρd–f, which contributed to a decline in ψ. When the negative influence of declining ψ outweighed the positive influence of the incrementing fv, the τ of the soil mixture decreased. Meanwhile, modelling of the τ–ψ relationship in the soil mixture with varying fv was performed. This proposed model was examined using the test results from both the present and previous studies, which shows its reasonably good performance. [ABSTRACT FROM AUTHOR]

Objectives: To develop a U-Net-based deep learning model for automated segmentation of craniopharyngioma. Methods: A total number of 264 patients diagnosed with craniopharyngiomas were included in this research. Pre-treatment MRIs were collected, annotated, and used as ground truth to learn and evaluate the deep learning model. Thirty-eight patients from another institution were used for independently external testing. The proposed segmentation model was constructed based on a U-Net architecture. Dice similarity coefficients (DSCs), Hausdorff distance of 95% percentile (95HD), Jaccard value, true positive rate (TPR), and false positive rate (FPR) of each case were calculated. One-way ANOVA analysis was used to investigate if the model performance was associated with the radiological characteristics of tumors. Results: The proposed model showed a good performance in segmentation with average DSCs of 0.840, Jaccard of 0.734, TPR of 0.820, FPR of 0.000, and 95HD of 3.669 mm. It performed feasibly in the independent external test set, with average DSCs of 0.816, Jaccard of 0.704, TPR of 0.765, FPR of 0.000, and 95HD of 4.201 mm. Also, one-way ANOVA suggested the performance was not statistically associated with radiological characteristics, including predominantly composition (p = 0.370), lobulated shape (p = 0.353), compressed or enclosed ICA (p = 0.809), and cavernous sinus invasion (p = 0.283). Conclusions: The proposed deep learning model shows promising results for the automated segmentation of craniopharyngioma. Key Points: • The segmentation model based on U-Net showed good performance in segmentation of craniopharyngioma. • The proposed model showed good performance regardless of the radiological characteristics of craniopharyngioma. • The model achieved feasibility in the independent external dataset obtained from another center. [ABSTRACT FROM AUTHOR]

Parachute mitral valve (PMV) is a common form of congenital mitral stenosis and is difficult to diagnose prenatally. This report describes a fetal case of PMV with coarctation of the aorta that was diagnosed at 25 weeks' gestation by echocardiography and confirmed at autopsy. We describe the ultrasonographic features in this case and present a useful sign for making a prenatal diagnosis of PMV. [ABSTRACT FROM AUTHOR]

Parachute mitral valve (PMV) is a common form of congenital mitral stenosis and is difficult to diagnose prenatally. This report describes a fetal case of PMV with coarctation of the aorta that was diagnosed at 25 weeks' gestation by echocardiography and confirmed at autopsy. We describe the ultrasonographic features in this case and present a useful sign for making a prenatal diagnosis of PMV. [ABSTRACT FROM AUTHOR]

Methods: The study included 59 patients with normal fetal heart structure, blood flow, and heart rhythm (fetal abnormality‐negative group) and 50 patients with abnormal fetal heart structure, blood flow, and/or heart rhythm (fetal abnormality‐positive group). Automated Cardiac Motion Quantification (aCMQ) was performed in both groups to obtain left and right ventricular endocardial global longitudinal strain (GLSendo), mid‐myocardial global longitudinal strain (GLSmid), and epicardial global longitudinal strain (GLSepi). Parameters between the two groups were compared and correlation analyses performed. A deformation analysis was performed by two trained observers, and reproducibility was assessed. Results: The fetal left ventricular and right ventricular global longitudinal strain (LV‐GLS and RV‐GLS, respectively) decreased in a gradient from the endocardium to the epicardium. LV‐GLS and RV‐GLS of all myocardial layers were lower in the fetal abnormality‐positive than ‐negative group (all P < 0.05). Correlation analysis showed that neither LV‐GLS nor RV‐GLS was significantly correlated with gestational age in the fetal abnormality‐negative group (all P > 0.05), whereas left ventricular GLSendo, GLSmid, and GLSepi were negatively correlated with gestational age in the fetal abnormality‐positive group (r = −.39 to −.44, all P < 0.05). Repeatability testing showed that the inter‐observer and intra‐observer intra‐class correlation coefficients for LV‐GLS and RV‐GLS in each myocardial layer were >.75 (all P < 0.001). Conclusions: As a new speckle tracking echocardiography tool, aCMQ has feasibility and repeatability in evaluating myocardial deformation of the fetal ventricle. This technique might provide helpful information on ventricular myocardial deformation in fetal hearts with abnormal structure or rhythm for clinical guidance in pregnancy. [ABSTRACT FROM AUTHOR]

Background: Placenta previa and accreta are serious obstetric conditions that are associated with a high risk of intraoperative massive hemorrhage, the prophylactic intravascular balloon occlusion technique is increasingly used in managing uncontrolled hemorrhage in cesarean section (CS). We aim to examine the clinical effectiveness of prophylactic balloon occlusion of the internal iliac artery (PBOIIA) during CS in improving maternal outcomes for patients with placenta previa and accreta.Methods: A total of 420 women with placenta previa and accreta who underwent CS from January 2014 to December 2018 were included retrospectively. Patients were divided into balloon group in which patients had PBOIIA (n = 248) and the control group in which patients did not have PBOIIA (n = 172). Meanwhile, we performed a subgroup analysis in whether taking parallel transverse uterine incision (PTUI) surgery. Information on conditions of patients and newborns, perioperative blood indicators, surgical outcomes were collected.Results: Median estimated blood loss (mEBL) was 2200 mL in the balloon group and 2150 mL in the control group respectively, there was no significant difference between two-groups comparison (P > 0.05), and the rate of patients with hysterectomy was also has no difference between the two groups (36.3% verus 35.5%, P > 0.05), while there is a significant difference between two groups in the amount of PRBCs transfused [3 (0-31.5) verus 3 (0-39), P <0.05], moreover, the proportion of PRBCS> 8 units in the balloon group is significantly lower than that in control group (11.29% verus 23.26%, P <0.05).. However, the total hospitalization costs (45,624.4 ± 11,061.9 verus 37,523.1 ± 14,662.2, CYN) and surgery costs (19,910.6 ± 2622.6 verus 11,850.5 ± 3146.1, CYN) in balloon group were significantly higher than those in control group (P < 0.05). Subgroup analysis showed PTUI surgery had no significant differences in EBL (P >0.05), but it could significantly decrease hysterectomy rates (P <0.05).Conclusions: PBOIIA has no significant effect on reducing intraoperative EBL and hysterectomy rate in patients with placenta previa and accreta. and although it could reduce the intraoperative PRBCs in patients with massive hemorrhage, it significantly increases the financial cost for patients. Therefore, PBOIIA should not be routinely recommended to patients with placenta previa and accreta. [ABSTRACT FROM AUTHOR]

Lotus seed has very high nutritional and medicinal value, which consists of lotus shell, lotus kernel and lotus core. Because of the bitter taste, the lotus cores need to be removed before eating. The existing equipment for removing core can remove the lotus core fast by operating the coring bit. Before drilling, the lotus kernel has to be centered in the centering working position. The centering device generally consists of two rotating rollers. Under the action of gravity and friction force, the lotus kernel can be centered in the rotating process. However, the position of the coring bit is fixed in the centering working position, and therefore the drilling deviation occurs due to the diameter variation of lotus kernels, and the lotus cores cannot be removed effectively, which lowers the quality of lotus kernels directly. To solve the above problems, the classification process is applied widely. However, it is ineffective owing to the inaccuracy of the classification process and the high requirement for staff and equipment. In order to avoid this situation, the shape parameters of lotus kernels are firstly measured and analyzed in this paper. The results show that the maximum cross section of the lotus kernel is almost round with a mean roundness deviation of 0.46 mm and the diameter ranges from 9 to 16 mm; the average chordwise curvature radius is 7.764 mm, and the average longitudinal curvature radius is 5.177 mm, therefore, the shape of a lotus kernel can approximate to an ellipsoid. Moreover, the centering deviation of the double roller rolling centering method presents a maximum value of 6.654 mm. Aiming at solving the problem of drilling deviation in the automated coring of lotus seeds, this paper proposes a self-adaptive centering method for lotus seeds based on a slider-crank mechanism and a parallel crank mechanism. By utilizing this method, the position of the coring bit can be automatically adjusted according to the lotus kernel size. A mathematical model of self-adaptive centering is established by the complex number vector method. Once the parameters of the linkages are selected, the centering deviation value is determined. For the self-adaptive centering mechanism, the optimization of the linkage parameters is complicated and difficult to meet the demand through traditional optimization methods. Therefore, in order to make the centering deviation minimum, by utilizing the stochastic optimization algorithm of Cuckoo Search, this paper optimizes the linkage parameters in MATLAB. The initial parameters are as follows: the nest number is 25, the probability of detection is 0.25, and the maximum iteration number is 4×105. The optimized parameters of connecting rod are 88.51, 135.72, 0.12828, and 125.35 mm respectively, and the coaxial deviation between the coring bit axis and lotus kernel axis is lower than 0.05mm. Based on the above study, a self-adaptive machine for removing core of lotus seed was developed and a coring experiment with 400 samples of lotus seeds was carried out. The experimental parameters were as follows: the working cycle was 1.5 s, the roller's rotating speed was 238 r/min, the pressure of the pressing wheel was 25 N, the coring bit diameter was 2.5 mm and the drill speed was 2800 r/min. By measuring the circle run-out value at the maximum cross section of the lotus kernel, the drilling accuracy of lotus seeds were calculated. The results show that the drilling accuracy of a self-adaptive machine for removing core of lotus seed is 91.25%, much higher than that of the existing equipment, which is 60%-70%; moreover, this machine can handle different sizes of lotus kernels. The experimental results verify the effectiveness and practicability of this self-adaptive centering method. [ABSTRACT FROM AUTHOR]

Background: Sacrococcygeal teratoma is one of the most common congenital tumors in newborns and infancy. The incidence is 1 per 20,000-40,000 live births. Ultrasonography is an optimal method for prenatal screening and diagnosis of fetal sacrococcygeal teratoma. MRI can be used to assist in the diagnosis. However, sacrococcygeal teratoma in the twin pregnancy is rare.Case Presentation: We reported a case of one twin with sacrococcygeal teratoma in dichorionic-diamniotic twin pregnancy.One twin with sacrococcygeal teratoma was diagnosed at the second trimester by ultrasonic examination and another twin was normal. A regular and careful antenatal care was conducted by the multidisciplinary team. The parents refused to perform the fetal MRI and examine the chromosome of both twin.At 37 + 1 of gestation, planned cesarean section was performed. The healthy male co-twin (twin A) weighed 2880 g.The male twin with SCT (twin B) weighed 2900 g, complying with 6 × 3 × 3 cm cystic and solid mass in sacrococcygeal region. At four days of age twin B underwent excisional surgery of the sacrococcygeal teratoma and coccyx and discharged 7 days after surgery. The mother and both babies were followed up and are all in good health until now.Conclusion(s): Sacrococcygeal teratoma in twin pregnancy is rare. Early antenatal diagnosis is important. Once the sacrococcygeal teratoma is diagnosed, clinicians should be aware of the associated maternal and fetal complications. Expecting parents should be counseled by the multidisciplinary team about the management and prognosis of the STC twin and co-twin. Prompt surgical excision of the sacrococcygeal teratoma after birth should be suggested. [ABSTRACT FROM AUTHOR]

Background: Hemivertebra deformity, involving one or multiple vertebral bodies, is one of the important causes of congenital scoliosis. Congenital fetal hemivertebrae could be diagnosed by ultrasonography and confirmed by fetal magnetic resonance imaging during pregnancy. However, reports of hemivertebrae in twins during the perinatal period are very rare.Case Presentation: We report two cases of congenital fetal hemivertebrae, each affecting one fetus in a dichorionic diamniotic (DCDA) twin pregnancy. We have also conducted a literature review of its prenatal screening, diagnosis, management, and outcomes. These two cases of congenital fetal hemivertebrae in one fetus of a DCDA twin were both initially found by ultrasonography and confirmed by fetal magnetic resonance imaging (MRI). One couple chose selective termination of the hemivertebrae fetus after they were extensively counseled by the multidisciplinary team regarding the treatment and prognosis of the hemivertebrae twin, and a healthy baby weighing 2320 g was delivered at the 37+ 1 gestational week. The other couple decided to continue the twin pregnancy and gave birth to two living newborns weighing 2580 g and 2060 g at 37+ 1 gestational weeks. These three babies were all in good health during follow-up.Conclusions: Based on our center's experience, comprehensive ultrasonography is necessary for early prenatal diagnosis of this condition. In addition, fetal MRI will confirm the diagnosis of hemivertebrae and provide parents with helpful information for their decision about the fate of the affected fetus. [ABSTRACT FROM AUTHOR]