In-line phase nano-tomography of human femoral bone in osteoporosis and osteoarthritis

International audience; X-ray in-line phase contrast tomography has been of growing interest in biology and medicine, since it enables non-destructive, quantitative 3D imaging of samples with very high sensitivity and spatial resolution. This is mainly enabled by the relatively large propagation distances of a highly spatially coherent beam that increase phase contrast interference fringes and also the use of cutting-edge detectors. Combined with tomographic reconstruction, it gives access to the refractive index distribution in the sample [1].Here, we used magnified in-line phase nano-tomography [2] to image human bone at the cellular level. This nano-imaging technique is similar to propagation-based phase contrast, except that the beam is focused using reflective X-ray optics. The sample is placed after the focal spot, so that the beam divergence and different propagation distances induce different magnification factors.Four human femoral cortical bone samples, one healthy, one suffering from osteoporosis (OP) and two suffering from osteoarthritis (OA), were imaged at the ID22 beamline at 60 nm pixel size. This resolution gives access to 3D imaging of the lacuno-canicular network (LCN) and matrix properties such as collagen fibril orientation and sub-micrometric mineralization. The field of view at this pixel size is ~120 μm, yielding a relatively large analysed volume compared to other 3D nano-tomographic techniques ([5], [6]).Quantitative analysis will be performed to determine relevant characteristics of the LCN, as well as collagen fibril orientation [3], and mineralization of the bone matrix [4]. We will investigate changes of these cell and matrix properties in OP and OA. This methodology can be applied in other studies, providing better understanding of the link between different pathologies and bone properties on the cellular length scale.[1] P. Cloetens, W. Ludwig, J. Baruchel, D. Van Dyck, J. Van Landuyt, J. P. Guigay, and M. Schlenker, Appl. Phys. Lett.,p. 2912, 1999.[2] M. Langer, A. Pacureanu, H. Suhonen, Q. Grimal, P. Cloetens, and F. Peyrin, PLoS One, p. e35691, 2012.[3] P. Varga, A. Pacureanu, M. Langer, H. Suhonen, B. Hesse, Q. Grimal, P. Cloetens, K. Raum, and F. Peyrin, EuropeanSociety of Biomechanics, 2013.[4] B. Hesse, M. Langer, P. Varga, A. Pacureanu, P. Dong, S. Schrof, N. Männicke, H. Suhonen, C. Olivier, P. Maurer, G.J. Kazakia, K. Raum, and F. Peyrin, Plos one, p. e88481, 2014.[5] M. Dierolf, A. Menzel, P. Thibault, P. Schneider, C. M. Kewish, R. Wepf, O. Bunk, and F. Pfeiffer, Nature, pp. 436–9,2010.[6] J. C. Andrews, E. Almeida, M. C. H. van der Meulen, J. S. Alwood, C. Lee, Y. Liu, J. Chen, F. Meirer, M. Feser, J. Gelb,J. Rudati, A. Tkachuk, W. Yun, and P. Pianetta, Microsc. Microanal., pp. 327–36, 2010.