Computing shortest cycles on discrete surfaces for acurate topological modifications of medical image isosurfaces.

Topological control over discrete isosurface is of primordial interest in medical applications, especially discrete model building for active contours. Previous attempts showed that the key point in acurately modifying topology was computation of shortest cycles on the surface of interest. This paper generalizes the shortest path algorithm to compute shortest cycles in a given homotopy class on a discrete surface with arbitrary topology.

Relevance of 2D radiographic texture analysis for the assessment of 3D bone micro-architecture.

Although the diagnosis of osteoporosis is mainly based on dual x-ray absorptiometry, it has been shown that trabecular bone micro-architecture is also an important factor in regard to fracture risk. In vivo, techniques based on high-resolution x-ray radiography associated to texture analysis have been proposed to investigate bone micro-architecture, but their relevance for giving pertinent 3D information is unclear. Thirty-three calcaneus and femoral neck bone samples including the cortical shells (diameter: 14 mm, height: 30-40 mm) were imaged using 3D-synchrotron x-ray micro-CT at the ESRF.