Standardisation and Validation of Micro-CT for the Morphological Characterisation of Porous Structures

In order to understand and to simulate the functional behaviour of porous structures during loading, quantitative knowledge of the relationship between the morphology and the mechanical behaviour is necessary. Therefore, the porous structures need to be quantified morphologically. In this research, the quantification will be performed by using micro-CT. However, to date, this technique encounters some problems. Optimal acquisition parameters still need to be found by ‘trial and error’, which is subjective and time consuming. Additionally, there is a lack of quantitative validation criteria. Both problems are tackled in this study, where, at this point, titanium bone scaffolds are assessed as proof of principle. By using a micro-CT simulator, theoretically optimal acquisition parameters are determined. These parameters are then used for the validation of micro-CT by means of metallographic slicing combined with optical microscopy. By matching the optical image with the micro-CT image of the same cross-section, validation criteria are defined. Based on three sliced parts of one Ti sample, a mean percentage in mismatch of 39.2 ± 7.8 % and in overlap of 75.6 ± 3.5 % with regards to the optical images is determined. To investigate whether these differences have a serious influence on the structural parameters, determined from the micro-CT images and the corresponding optical images, further image analysis is performed.