Methodological diversity in micro-CT evaluation of bone micro-architecture: Importance for inter-study comparability

Abstract

Introduction: Micro-computed tomography (micro-CT) is a standard 3D technique for non-destructive analysis of bone micro-architecture. Although there have been many micro-CT studies in contemporary literature, inter-study comparability is often challenging due to a lack of methodological standardization, particularly regarding human bone analyses. Aim: This study aimed to assess the consistency of micro-CT generated micro-architectural parameters obtained by two researchers (inter-observer reliability), by one researcher in two attempts (intra-observer reliability), as well as between manual and semi-automatic determination of the region of interest (ROI). Material and methods: Superolateral femoral neck samples (n=8) were scanned with Bruker 1172 micro-CT system with a voxel size of 10 µm. We manually determined cortical and trabecular ROI (two authors, two attempts with a 45-day span). Also, trabecular ROI was determined using a semi-automatic method (round-shaped ROI with 6.5 mm diameter). Results: The intraclass correlation coefficient (ICC) showed a high degree of consistency in the measurement of micro-architectural parameters of the superolateral femoral neck using the micro-CT (ICC range: 0.721-0.998; p<0.05). However, a detailed analysis revealed significant inter-observer and intra-observer differences, predominantly reflected in cortical porosity parameters (Student's t-test for dependent samples, p<0.05). On the other hand, the choice of ROI did not significantly affect trabecular micro-architectural parameters among researchers and between manual and semi-automatic demarcation methods (Student's t-test for dependent samples, p>0.05). Conclusion: Our study emphasizes the importance of standardizing the methodology used in micro-CT evaluations of human bone samples, which could facilitate reliable inter-study comparison and ensure an adequate interpretation of results.