High-resolution computed tomography for architectural characterization of human lumbar cancellous bone: Relationships with histomorphometry and biomechanics

The aim of the present study on human vertebral cancellous bone was to vali date structural parameters measured with high-resolution (150 mu m) compute d tomography (HRCT) by referring to histomorphometry and to try to predict mechanical properties of bone using HRCT. Two adjacent vertical cores were removed from the central part of human L2 vertebral body taken after necrop sy in 22 subjects aged 47-95 years (10 women, 12 men; mean age 79 +/- 14 ye ars). The right care was used for structural analysis performed by both HRC T and histomorphometry. Two cancellous bone specimens were extracted from t he left core: a cube for HRCT and a compression test, and a cylinder for a sheer test. Significant correlations were found between HRCT and histomorph ometric measurements (BV/TV, trabecular thickness, separation and number, a nd node-strut analysis), but with higher values for most of the tomographic parameters (BV/TV and trabecular thickness determined by HRCT were overest imated by a factor 3.5 and 2.5 respectively, as compared with histomorphome try). The maximum compressive strength and Young's modulus were highly corr elated (p = 0.99, p<0.0005). Significant con-elation was obtained between b one mineral density (determined using dual-energy X-ray absorptiometry) and the maximum compressive strength (p = 0.64, p = 0.002). In addition the ma ximum compressive strength and architectural parameters determined by HRCT significant correlations (e.g., for HRCT, BV/TV: p=0.88, p<0.0005, N.Nd/TV: p = 0.73, p<0.001). The shear strength was significantly correlated with B V/TV (p = 0.62, p = 0.002), Tb.Sp (p = -0.58, p = 0.004) and TSL (p = 0.55, p = 0.006) measured by HRCT. In conclusion, an HRCT system with 150 mu m r esolution is not sufficient to predict the true values of the structural pa rameters measured by histomorphometry, although high correlations were foun d between the two methods. However, we showed that a resolution of 150 um a llowed us to predict the mechanical properties of human cancellous bone. In vivo peripheral systems with such a resolution should be of interest and w ould deliver an acceptable radiation dose to the patient.