Caractérisation 3d d'images IRM pour l'analyse de l'ostéochondrite primitive de la hanche

- L'interface utilisateur développée fournit des indices coxométriques pour caractériser l'état global de l'articulation de la hanche. Le logiciel 3D Slicer sert d'interface pour la visualisation 3D. La technique des ensembles de niveaux est utilisée pour segmenter chaque type de structure. Elle s'adapte à la topologie de la maladie à caractériser (fragmentation) et au type d'examen IRM (T1 ou T2). Un modèle géométrique est ensuite construit. Des indices géométriques tridimensionnels sont calculés automatiquement : excentration de la tête, volume de la tête, volume des cartilages céphalique et acétabulaire, distance tête-cotyle. Ces mesures exploitent l'ensemble des images planes IRM et quantifient les déformations liées à la maladie. Elles peuvent servir à préparer une intervention chirurgicale ou à surveiller l'évolution de la maladie

Comparison of patient-specific computational models vs. clinical follow-up, for adjacent segment disc degeneration and bone remodelling after spinal fusion

Spinal fusion is a standard surgical treatment for patients suffering from low back pain attributed to disc degeneration. However, results are somewhat variable and unpredictable. With fusion the kinematic behaviour of the spine is altered. Fusion and/or stabilizing implants carrying considerable load and prevent rotation of the fused segments. Associated with these changes, a risk for accelerated disc degeneration at the adjacent levels to fusion has been demonstrated. However, there is yet no method to predict the effect of fusion surgery on the adjacent tissue levels, i.e. bone and disc. The aim of this study was to develop a coupled and patient-specific mechanoregulated model to predict disc generation and changes in bone density after spinal fusion and to validate the results relative to patient follow-up data. To do so, a multiscale disc mechanoregulation adaptation framework was developed and coupled with a previously developed bone remodelling algorithm. This made it possible to determine extra cellular matrix changes in the intervertebral disc and bone density changes simultaneously based on changes in loading due to fusion surgery. It was shown that for 10 cases the predicted change in bone density and degeneration grade conforms reasonable well to clinical follow-up data. This approach helps us to understand the effect of surgical intervention on the adjacent tissue remodelling. Thereby, providing the first insight for a spine surgeon as to which patient could potentially be treated successfully by spinal fusion and in which patient has a high risk for adjacent tissue changes

Relationships between density and Young's modulus with microporosity and physico-chemical properties of Wistar rat cortical bone from growth to senescence.

International audienc

Micro-macro characterization and modelling of human cortical bone : structural anisotropy versus material anisotropy.

Plenary ConferenceInternational audienc

Multi-scale characterization and modelling of human cortical bone.

November 28 - December 2, Boston, MA US