Apport de l'imagerie médicale 3D à l'étude d'une momie du IVe siècle av. J.-C.

International audienceEn 2005, une momie retrouvée dans une tombe datant du IV e siècle a.C. dans la nécropole de Saqqara par l'équipe du musée du Louvre a été scannée au musée du Caire pour les besoins de la réalisation d'un film. La reprise des données collectées à cette occasion par un jeune ingénieur informaticien a permis de traiter et de réunir les fichiers qui n'avaient pas toute la même définition et ainsi de montrer l'apport de l'imagerie médicale pour fournir aux spécialistes des images virtuelles du corps et du squelette de la momie. Abstract : In 2005, for the making of a film, experts in the Cairo museum performed a scan on a mummy discovered in a tomb dating from the 4th century BC in the Saqqara necropolis. The mummy was discovered by the archaeological team of the Louvre museum. The data of the scan were subsequently studied by a young computer engineer, who managed to assemble the numerous files despite the fact that they were different in terms of precision. From this we can see the particular utility of medical imagery which can provide specialists with virtual images of the mummy's skeleton and body

Apport de l'imagerie médicale 3D à l'étude d'une momie du IVe s. av. J.-C

International audienceIn 2005, for the making of a film, experts in the Cairo museum performed a scan on a mummy discovered in a tomb dating from the 4th century BC in the Saqqara necropolis. The mummy was discovered by the archaeological team of the Louvre museum.The data of the scan were subsequently studied by a young computer engineer, who managed to assemble the numerous files despite the fact that they were different in terms of precision. From this we can see the particular utility of medical imagery which can provide specialists with virtual images of the mummy’s skeleton and bodyEn 2005, une momie retrouvée dans une tombe datant du IVe siècle a.C. dans la nécropole de Saqqara par l’équipe du musée du Louvre a été scannée au musée du Caire pour les besoins de la réalisation d’un film. La reprise des données collectées à cette occasion par un jeune ingénieur informaticien a permis de traiter et de réunir les fichiers qui n’avaient pas toute la même définition et ainsi de montrer l’apport de l’imagerie médicale pour fournir aux spécialistes des images virtuelles du corps et du squelette de la momi

Quantitative CT imaging for adipose tissue analysis in mouse model of obesity

International audienceIn obese humans CT imaging is a validated method for follow up studies of adipose tissue distribution and quantification of visceral and subcutaneous fat. Equivalent methods in murine models of obesity are still lacking. Current small animal micro-CT involves long-term X-ray exposure precluding longitudinal studies. We have overcome this limitation by using a human medical CT which allows very fast 3D imaging (2 sec) and minimal radiation exposure. This work presents novel methods fitted to in vivo investigations of mice model of obesity, allowing (i) automated detection of adipose tissue in abdominal regions of interest, (ii) quantification of visceral and subcutaneous fat. For each mouse, 1000 slices (100μm thickness, 160 μm resolution) were acquired in 2 sec using a Toshiba medical CT (135 kV, 400mAs). A Gaussian mixture model of the Hounsfield curve of 2D slices was computed with the Expectation Maximization algorithm. Identification of each Gaussian part allowed the automatic classification of adipose tissue voxels. The abdominal region of interest (umbilical) was automatically detected as the slice showing the highest ratio of the Gaussian proportion between adipose and lean tissues. Segmentation of visceral and subcutaneous fat compartments was achieved with 2D ½ level set methods. Our results show that the application of human clinical CT to mice is a promising approach for the study of obesity, allowing valuable comparison between species using the same imaging materials and software analysi

New CT imaging method for adipose tissue analysis in mouse model of obesity

In humans CT imaging is a validated method for the study of adipose tissue distribution and for quantification of visceral and subcutaneous fat. Equivalent methods adapted to murine models of obesity are still lacking. Indeed most attempts to quantify fat tissues in vivo, using dedicated small animal micro-CT, involve long-term X-ray exposure which limits longitudinal studies. We have overcome this limitation by using a human clinical CT which allows very fast 3D imaging and minimal radiation exposure for the study of adipose tissue distribution in mice in vivo. Moreover, we have developed an automatic image analysis method for the segmentation of Hounsfield units of adipose tissues and for the localization of abdominal regions of interest

3D visualization and quantification of bone and teeth mineralization for the study of osteo/dentinogenesis in mice models

International audienceResearch on bone and teeth mineralization in animal models is critical for understanding human pathologies. Genetically modified mice represent highly valuable models for the study of osteo/dentinogenesis defects and osteoporosis. Current investigations on mice dental and skeletal phenotype use destructive and time consuming methods such as histology and scanning microscopy. Micro-CT imaging is quicker and provides high resolution qualitative phenotypic description. However reliable quantification of mineralization processes in mouse bone and teeth are still lacking. We have established novel CT imaging-based software for accurate qualitative and quantitative analysis of mouse mandibular bone and molars. Data were obtained from mandibles of mice lacking the Fibromodulin gene which is involved in mineralization processes. Mandibles were imaged with a micro-CT originally devoted to industrial applications (Viscom, X8060 NDT). 3D advanced visualization was performed using the VoxBox software (UsefulProgress) with ray casting algorithms. Comparison between control and defective mice mandibles was made by applying the same transfer function for each 3D data, thus allowing to detect shape, colour and density discrepencies. The 2D images of transverse slices of mandible and teeth were similar and even more accurate than those obtained with scanning electron microscopy. Image processing of the molars allowed the 3D reconstruction of the pulp chamber, providing a unique tool for the quantitative evaluation of dentinogenesis. This new method is highly powerful for the study of oro-facial mineralizations defects in mice models, complementary and even competitive to current histological and scanning microscopy appoaches