Quantification de l'architecture osseuse par microtomographie 3D utilisant le rayonnement synchrotron

Nous présentons un système de microtomographie 3D par rayonnement synchrotron développé à l'ESRF de Grenoble, en vue de l'analyse de la structure trabéculaire osseuse. Ce système permet d'acquérir de façon non destructive des images 3D d'échantillons osseux , ayant des voxels isotrope de 6.65 μm. Afin de caractériser la structure 3D de l'os, des paramètres quantitatifs sont extraits de ces images. Les paramètres morphologiques et topologiques utilisés en histomorphométrie, sont calculés sur les différentes coupes du volume. La variabilité des paramètres dans l'échantillon et la nécessité d'une analyse réellement tridimensionnelle sont soulignés. L'influence de la résolution spatiale sur l'exactitude des paramètres calculés est également examinée

被服に対する意識及び行動とそれに影響する要因

博士（学術）神戸大

Scanographie d'une momie égyptienne, antique, d'enfant et d'une momie péruvienne, ancienne, d'adulte

COMPUTED TOMOGRAPHY OF AN AEGYPTIAN, ANTIQUE CHILD MUMMY AND OF A PERUVIAN, ANCIENT ADULT MUMMY Summary. — Two mummies : aegyptian, antique child, and Peruvian, ancient adult were C.T.-scanned (C.G.R. apparatus, C.E. 10 000) with systematical seriation. The aegyptian child (№ 23-714, Laboratoire d'Anthropologie du Muséum National d'Histoire Naturelle, Paris, Musée de l'Homme) offered several objects within the wrapping, easily localized by C.T.-scan sections which permitted to precise several details of the embalming technic. Important perturbations of the cranio-cervical junction were due to the excerebration by anterior and rostral approach and to introduction of resinous substances in the posterior fossa ; flattening of the thorax, fracture - luxation of the thoraco-lumbard junction, sacro-iliac dislocation and hip luxations could be due to close tightening by the wraps. The age can be estimated to 28 months old by intra-cranial diameter measurements and 34 months by femoral length. The peruvian adult (№ 23-557, same origin) kept its viscera in situ, strongly reduced by dessicative effect. Two vertebral abscesses were revealed by C.T.-scan and then retrieved on X-ray radiographs. Special position of the limbs with hyperflexion along the trunk give to the sections unusual aspects, particularly on the level of the principal joints.Résumé. — Deux momies : égyptienne, antique, d'enfant, et péruvienne ancienne d'adulte ont été scanographiées (appareil C.G.R., CE. 10 000) en série systématique. L'enfant égyptien (N° 23-714, Laboratoire d'Anthropologie du Muséum National d'Histoire Naturelle, Paris, Musée de l'Homme) présentait plusieurs objets inclus dans les bandelettes, facilement localisés par les coupes scanographiques qui permettent de détailler de nombreux points techniques de l'embaumement. Des remaniements importants de la charnière crânio-rachidienne étaient liées à l'excérébration par voie rachidienne haute, antérieure et à l'introduction de résine dans la fosse postérieure ; l'aplatissement du thorax, une fracture-luxation de la charnière dorso-lombaire, la dislocation des articulations sacro-iliaques et la luxation des hanches peuvent être attribués au serrage par les bandelettes. L'âge est estimé à 28 mois par la mesure des diamètres intra-crâniens et 34 mois par la mesure de la longueur du fémur. L'adulte péruvien (№ 23-557, même origine) conservait la totalité de ses viscères en place, rétractés par la dessication. Deux abcès vertébraux ont été décelés par la scanographie et retrouvés sur les radiographies. La position des membres en hyperflexion le long du tronc confère aux coupes un aspect inhabituel, particulièrement aux niveaux articulaires.Le Floch-Prigent P., Laval-Jeantet M. Scanographie d'une momie égyptienne, antique, d'enfant et d'une momie péruvienne, ancienne, d'adulte. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, XIV° Série. Tome 3 fascicule 2, 1986. pp. 117-139

Scanographie d'une momie égyptienne antique de nourrisson et de deux fausses momies de nouveau-nés

C.T.-SCAN OF AN ANCIENT EGYPTIAN INFANT MUMMY AND OF TWO MUMMIFORM OBJECTS Summary. — Three mummies classified as antic ones, are studied by C.T.-scan (C.G.R., N.D. 10 000). This examination, allows by systematical seriation to precise several mummification's modalities and several anatomical characteristics (age, sex, pathology) on the only genuine mummy : an egyptian one, 6-8 months old girl. The intracranial cavity is empty, a dense mass occupies the oral and nasal pharyngeal cavity ; several objects are detected into the envelopes out and into the corpse. The two other mummiform objects do not contain human remains : the first one, simulates an egyptian mummy, and is made of seven main pieces of wood wrapped with thin layers of tissue, C.T.-scan defines with accuracy the set and the morphology of the components ; the second one contains various materials and one facial mask, its authenticity as an ancient ethiopan set is quite certain.Résumé. — Trois momies répertoriées comme antiques sont étudiées par scanographie (appareil C.G.R., CE. 10 000). Cet examen permet grâce à la sériation systématique tous les centimètres de préciser plusieurs des conditions de momification et de nombreux caractères anatomiques (âge, sexe, lésions) de la seule momie authentique : celle d'un nourrisson égyptien, fillette de 6 à 8 mois. La cavité intra-crânienne est vide, un emplâtre dense occupe le rhino et l'oro-pharynx ; plusieurs objets sont décelés à l'intérieur des bandelettes tant en dehors qu'en dedans du corps. Les deux autres objets momiformes ne contiennent pas de restes humains : le premier, simule une momie égyptienne et se compose de sept pièces de bois, recouvertes de bandelettes peu épaisses dont la scanographie a précisé le mode d'assemblage et la forme ; le second est un modèle en matériaux composites avec masque facial anthropomorphe dont l'authenticité ancienne et éthiopienne est vraisemblable.Sotto-Heim P., Le Floch-Prigent P., Laval-Jeantet M. Scanographie d'une momie égyptienne antique de nourrisson et de deux fausses momies de nouveau-nés. In: Bulletins et Mémoires de la Société d'anthropologie de Paris, XIV° Série. Tome 2 fascicule 2-3, 1985. pp. 115-139

MR imaging of intravoxel incoherent motions: application to diffusion and perfusion in neurologic disorders.

International audienceMolecular diffusion and microcirculation in the capillary network result in a distribution of phases in a single voxel in the presence of magnetic field gradients. This distribution produces a spin-echo attenuation. The authors have developed a magnetic resonance (MR) method to image such intravoxel incoherent motions (IVIMs) by using appropriate gradient pulses. Images were generated at 0.5 T in a high-resolution, multisection mode. Diffusion coefficients measured on images of water and acetone phantoms were consistent with published values. Images obtained in the neurologic area from healthy subjects and patients were analyzed in terms of an apparent diffusion coefficient (ADC) incorporating the effect of all IVIMs. Differences were found between various normal and pathologic tissues. The ADC of in vivo water differed from the diffusion coefficient of pure water. Results were assessed in relation to water compartmentation in biologic tissues (restricted diffusion) and tissue perfusion. Nonuniform slow flow of cerebrospinal fluid appeared as a useful feature on IVIM images. Observation of these motions may significantly extend the diagnostic capabilities of MR imaging

Micro‐CT examinations of trabecular bone samples at different resolutions: 14, 7 and 2 micron level

International audienceTomographic techniques are attractive for the investigation of trabecular bone architecture. Using either conventional X‐ray sources or synchrotron sources currently allows the acquisition of 3D images in a wide range of spatial resolution that may be as small as a few micrometers. Since it is technically possible to examine trabecular architecture at different scales, a question is to know what type of information it is possible to get at each scale. For this purpose, a series of ten vertebrae samples from healthy females of different ages (33 to 90) was imaged at various resolutions on three different micro‐CT systems (cubic voxel size respectively 14, 6.7 and 1.4 \mum). The comparison of morphometric parameters extracted from the different images is in agreement with simulation results on the influence of spatial resolution on structure parameters. The conclusion is that a 14 \mum voxel size gives a reasonably good parameterisation of trabecular architecture. Besides the synchrotron radiation 2 \mum level images reveal interesting features on the irregularities and rupture of trabecular surface, and on remodeling zones

3D display of high resolution vertebral structure images

International audienceA methodology for three-dimensional (3D) representation of vertebral trabecular structures was proposed. A set of X-ray CT images was obtained using a specific high resolution acquisition system. The images were then segmented in order to separate trabecular and cortical bone structures. Finally, the complex 3D surfaces were visualized using a volume rendering techniqu

Dual X-ray absorptiometry--cross-calibration and normative reference ranges for the spine: results of a European Community Concerted Action.

Bone density measurements by dual X-ray absorptiometry (DXA) of the spine can now be made precisely, but there is no uniformity in reporting results and in presenting reference data. A European Union Concerted Action therefore devised a uniform procedure for cross-calibrating and standardizing instruments, using the European spine phantom (ESP) prototype. This phantom differs in a number of respects from the final version of the ESP. Eighteen centers in nine countries obtained 1619 records (1035 women) from Caucasian subjects, aged 20-80 years, drawn from normal populations. The DXA machines used were made by the Hologic, Lunar, and Norland companies. Highly statistically significant differences were evident between populations, both in apparent rates of bone loss with age and in the spread of values about the age-adjusted means. There were small residual differences in the results obtained with the three machine brands which could have been due to the relatively large between-center population differences we observed. The alternative or additional explanation that they were attributable, in part, to the design differences between the ESP prototype and the definitive ESP, which became available after this study was completed, was shown to be a valid possibility. Results from postmenopausal women reported in relation to the years that have elapsed since menopause showed reduced population variance when compared with conventional reporting in relation to age. After cross-calibration, the center with the highest age-adjusted normal density value averaged 23% more than the center with the lowest. It is therefore crucially important to select appropriate reference data in clinical and epidemiological studies.(ABSTRACT TRUNCATED AT 250 WORDS

European semi-anthropomorphic spine phantom for the calibration of bone densitometers: assessment of precision, stability and accuracy. The European Quantitation of Osteoporosis Study Group.

Up to now it has not been possible to reliably cross-calibrate dual-energy X-ray absorptiometry (DXA) densitometry equipment made by different manufacturers so that a measurement made on an individual subject can be expressed in the units used with a different type of machine. Manufacturers have adopted various procedures for edge detection and calibration, producing various normal ranges which are specific to each individual manufacturer's brand of machine. In this study we have used the recently described European Spine Phantom (ESP, prototype version), which contains three semi-anthropomorphic "vertebrae" of different densities made of stimulated cortical and trabecular bone, to calibrate a range of DXA densitometers and quantitative computed tomography (QCT) equipment used in the measurement of trabecular bone density of the lumbar vertebrae. Three brands of QCT equipment and three brands of DXA equipment were assessed. Repeat measurements were made to assess machine stability. With the large majority of machines which proved stable, mean values were obtained for the measured low, medium and high density vertebrae respectively. In the case of the QCT equipment these means were for the trabecular bone density, and in the case of the DXA equipment for vertebral body bone density in the posteroanterior projection. All DXA machines overestimated the projected area of the vertebral bodies by incorporating variable amounts of transverse process. In general, the QCT equipment gave measured values which were close to the specified values for trabecular density, but there were substantial differences from the specified values in the results provided by the three DXA brands. For the QCT and Norland DXA machines (posteroanterior view), the relationships between specified densities and observed densities were found to be linear, whereas for the other DXA equipment (posteroanterior view), slightly curvilinear, exponential fits were found to be necessary to fit the plots of observed versus specified densities. From these plots, individual calibration equations were derived for each machine studied. For optimal cross-calibration, it was found to be necessary to use an individual calibration equation for each machine. This study has shown that it is possible to cross-calibrate DXA as well as QCT equipment for the measurement of axial bone density. This will be of considerable benefit for large-scale epidemiological studies as well as for multi-site clinical studies depending on bone densitometry