73 research outputs found

    Anatomically constrained CT image translation for heterogeneous blood vessel segmentation

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    Anatomical structures such as blood vessels in contrast-enhanced CT (ceCT) images can be challenging to segment due to the variability in contrast medium diffusion. The combined use of ceCT and contrast-free (CT) CT images can improve the segmentation performances, but at the cost of a double radiation exposure. To limit the radiation dose, generative models could be used to synthesize one modality, instead of acquiring it. The CycleGAN approach has recently attracted particular attention because it alleviates the need for paired data that are difficult to obtain. Despite the great performances demonstrated in the literature, limitations still remain when dealing with 3D volumes generated slice by slice from unpaired datasets with different fields of view. We present an extension of CycleGAN to generate high fidelity images, with good structural consistency, in this context. We leverage anatomical constraints and automatic region of interest selection by adapting the Self-Supervised Body Regressor. These constraints enforce anatomical consistency and allow feeding anatomically-paired input images to the algorithm. Results show qualitative and quantitative improvements, compared to stateof-the-art methods, on the translation task between ceCT and CT images (and vice versa).Comment: Accepted at BMVC 202

    Research perspectives in the etiology of congenital anorectal malformations using data of the International Consortium on Anorectal Malformations: evidence for risk factors across different populations

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    Contains fulltext : 89406.pdf (publisher's version ) (Closed access)PURPOSE: The recently established International Consortium on Anorectal Malformations aims to identify genetic and environmental risk factors in the etiology of syndromic and nonsyndromic anorectal malformations (ARM) by promoting collaboration through data sharing and combined research activities. METHODS: The consortium attempts to recruit at least 1,000 ARM cases. DNA samples are collected from case-parent triads to identify genetic factors involved in ARM. Several genetic techniques will be applied, including SNP arrays, gene and whole exome sequencing, and a genome-wide association study. Questionnaires inquiring about circumstances before and during pregnancy will be used to obtain environmental risk factor data. RESULTS: Currently, 701 ARM cases have been recruited throughout Europe. Clinical data are available from all cases, and DNA samples and questionnaire data mainly from the Dutch and German cases. Preliminary analyses on environmental risk factors in the Dutch and German cohort found associations between ARM and family history of ARM, fever during first trimester of pregnancy and maternal job exposure to cleaning agents and solvents. CONCLUSION: First results show that both genetic and environmental factors may contribute to the multifactorial etiology of ARM. The International Consortium on Anorectal Malformations will provide possibilities to study and detect important genes and environmental risk factors for ARM, ultimately resulting in better genetic counseling, improved therapies, and primary prevention.1 november 201

    Immature Cryopreserved Ovary Restores Puberty and Fertility in Mice without Alteration of Epigenetic Marks

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    BACKGROUND: Progress in oncology could improve survival rate in children, but would probably lead to impaired fertility and puberty. In pre-pubertal girls, the only therapeutic option is the cryopreservation of one ovary. Three births have been reported after reimplantation of cryopreserved mature ovary. Conversely, reimplantation of ovary preserved before puberty (defined as immature ovary) has never been performed in humans. METHODOLOGY/PRINCIPAL FINDINGS: In order to analyze ovarian function, we performed transplantation using fresh or cryopreserved immature grafts in pre-pubertal or adult mice. Puberty as well as cyclic hormonal activity was restored. All follicle populations were present although a significant reduction in follicle density was observed with or without cryopreservation. Although fertility was restored, the graft is of limited life span. Because ex vivo ovary manipulation and cryopreservation procedure, the status of genomic imprinting was investigated. Methylation status of the H19 and Lit1 Imprinting Control Regions in kidney, muscle and tongue of offsprings from grafted mice does not show significant alteration when compared to those of unoperated mice. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that immature ovarian grafting can restore spontaneous puberty and fertility. However, these data suggest that follicle depletion leads to premature ovarian failure. This study addresses the very important epigenetics issue, and provides valuable information to the study of ovarian transplantation suggesting that these procedures do not perturb normal epigenetics marks. These results are highly relevant to the reimplantation question of immature cortex in women

    A new rat model of prenatal bowel obstruction: development and early assessment.

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    International audiencePURPOSE: Although intestinal motility disorders often complicate the postoperative surgical management of newborns with congenital intestinal atresia, their pathogenesis remains unclear. Animal models of prenatal intestinal obstruction have been mainly developed in the lamb and the chicken. Despite new insights brought by these models, they have one or more limitations, such as high fetal mortality rates, high costs, long gestation periods, and an insufficient number of fetuses per litter. Moreover, some species are phylogenetically distant from mammals. METHODS: We developed a reproducible model of prenatal intestinal obstruction in the rat to study the histologic changes induced by the obstruction. We report, the technical devices and the first assessment of this atresia model in a didactic way to allow other researchers to easily reproduce the model. RESULTS: Prenatal intestinal obstructions in this study fulfilled all the macroscopic and histologic criteria usually listed by other models of prenatal intestinal obstruction that have been developed in other species. Furthermore with our model, we obtained a high success rate at a low cost. CONCLUSIONS: We presented in this study a reproducible model of prenatal intestinal obstruction in the rat with the macroscopical and histologic features of prenatal intestinal obstruction

    Validation of the French versions of the Hirschsprung\u2019s disease and Anorectal malformations Quality of Life (HAQL) questionnaires for adolescents and adults

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    Abstract Background The Hirschsprung\u2019s disease Anorectal malformation QoL questionnaire (HAQL) is a disease-specific quality of life (QoL) questionnaire for patients with Hirschsprung\u2019s disease (HD) or anorectal malformations (ARM). It was originally proposed in Dutch and is currently being translated into other languages to obtain an internationally standardized instrument. In this work we validate a French adaptation of the HAQL for adolescents and adults. Methods The questionnaires were translated into French and sent to patients aged 12\ua0years and older, followed for HD or ARM at three French university hospitals. Questionnaires were sent to 147 adolescents and 188 adults. The psychometric properties of the questionnaires were analyzed in terms of reliability and validity. Results The original HAQL structure was not satisfactory. A new structure was proposed, while aiming to remain close to the original structure. The proposed structure has acceptable reliability and validity properties and reflects both physical, as well as psychosocial aspects. Conclusions A French version of the HAQL questionnaire for adults and adolescents is ready for use in France. In particular the score could discriminate between degrees of clinical status based on the Krickenbeck consensus, which can aid clinicians to inform patients about physical and psychosocial challenges they may expect

    A new method based on template registration and deformable models for pelvic bones semi-automatic segmentation in pediatric MRI

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    International audience<p>In this paper we address the problem of bone segmentation in MRIimages of children, in the region of the pelvis. To cope with the complex structure of the bones in this region and their changing topologyduring growth, we propose a method relying on 3D bone templates.These models are built from 3D CT images. For a given MRI volume, the closest template is chosen and registered on the MRI data.This leads to an initial segmentation which is then refined using a deformable model approach, where the regularization parameters depend on the local curvature, and the landmarks used during the registration are fixed anchors during the deformation. This approach wassuccessfully applied to 15 MRI volumes of children between 1 and18 years old, with an average accuracy in terms of medium distanceof M D = 1.17 ± 0.29 mm and Dice Index of DC = 0.81 ± 0.04.</p
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