3D X-ray CT imaging of the bone Lacuno-Canalicular Network

Imaging of the trabecular bone network has made significant advances in the last decade thanks to the outstanding development of 3D X-ray micro-CT. Compared to standard histomorphometry, this technique provides non-destructively 3D images of the trabecular bone permitting a so-called model-independent quantification of this network. Today, the assessment of the bone Lacuno-Canalicular Network (LCN) is a new challenge at the cellular scale. The LCN forms a communication network interconnecting the osteocytes, the bone cells embedded in the mineralized matrix. It plays a major role in mechanotransduction with important implications on bone remodeling and finally bone strength. However, methods for the 3D assessment of the LCN are lacking. In a recent work, we have shown the feasibility of imaging the LCN in 3D thanks to Synchrotron Radiation nano-CT (voxel size 280 nm). These first images of the LCN in 3D open new challenges in image processing to segment and quantify the LCN. After recalling the principle of image acquisition, we present our first approaches for enhancing the contrast of canaliculi and segmenting the LCN. Finally, to increase the connectivity of the network, we consider a new approach based on 3D geodesic voting, offering promising perspectives. Results on experimental 3D images of the 3D LCN in human femoral bone are presented.